West Virginia University Jaxson S. Judkins West Virginia University Follow this and additional works at: https://researchrepository.wvu.edu/etd Part of the Other Psychology Commons, and the Sports Studies Commons Recommended Citation Judkins, Jaxson S., "Examining the Online Marketing of Sport Psychology Services by Certified Mental Performance Consultants: A Rhetorical Analysis" (2024). Graduate Theses, Dissertations, and Problem Reports. 12648. https://researchrepository.wvu.edu/etd/12648 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact researchrepository@mail.wvu.edu. Examining the Online Marketing of Sport Psychology Services by Certified Mental Performance Consultants: A Rhetorical Analysis Jaxson S. Judkins, M.A. Dissertation submitted to the College of Applied Human Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Sport, Exercise, and Performance Psychology Sam Zizzi, Ed.D., Chair Lisa Platt, Ph.D. D. Jake Follmer, Ph.D. Adam Zundell, M.S. School of Sport Sciences Morgantown, West Virginia 2024 Keywords: persuasion, rhetoric, sport psychology services, social media, marketing Copyright 2024 Jaxson S. Judkins Abstract Examining the Online Marketing of Sport Psychology Services by Certified Mental Performance Consultants: A Rhetorical Analysis Jaxson Judkins, M.A. In recent years, Certified Mental Performance Consultants (CMPCs) have increased their footprint in social media to connect with those that seek sport psychology services (Cotterill & Symes, 2014). The aim of this study was to identify what social media platforms are most used among CMPCs and what persuasive elements are used to draw in potential clients. All active CMPCs from 1992 to 2023 were examined to determine the most popular social media platforms used, followed by an analysis of 219 CMPCs based on their ownership of a LinkedIn account and professional website. Results indicated that LinkedIn and the consultants’ custom professional website were the most popular online platforms used. The most common rhetorical strategies used included authority, ethos, and pathos to market the benefits of their consulting services to the public. Lastly, master’s level CMPCs used reciprocity and social proof in greater volume, whereas doctoral level CMPCs leaned more on authority to establish persuasiveness. Future research could explore short video content produced by CMPCs on social media platforms to gain new insights into consumer engagement with sport psychology services. iii Acknowledgements “A tame horse never made a skilled rider” became my mantra during this Ph.D. journey, drawing upon my childhood riding horses and the reality that every fall is another opportunity to dust myself off and become more refined. I knew that I would get “bucked off” with no warning along the Ph.D. path, but I knew I could accomplish this endeavor if given the chance. What I couldn’t predict was the amount of support I received from those around me; their encouragement to get back in the saddle and ride on. Reflecting on this journey, I am filled with a deep sense of gratitude for those that stood by me during this wild ride and this message is to them: To Dr. Zizzi, no doubt, I got “lost in literature forest” or better said, “bathed” in it for far too long trying to create the perfect study, but you were always there to help me get out of my own way. You are my research mountain “sherpa”, the one that guided, encouraged, and at times, carried me through the rugged research terrain to reach the summit. Your charisma and wisdom are unmatched and with alternative rock music in the background, I can still hear your voice saying, “If you get lost in literature forest and no one hears your scream, then you’re in the right place.” My experience at WVU has been shaped by your example and approach to life. Your willingness to take me in as one of your adopted students these last two years has meant so much to me. You showed me what I am capable of and pushed me beyond my limits. I greatly appreciate your patience through thick and thin. Because of your mentorship, you gave me the “climbing anchors” needed to reach the top. I am indebted to you in more ways than you know. Thank you for believing in me. To my committee, I want to send my most sincere gratitude to Dr. Platt, Dr. Follmer, and Mr. Zundell who guided me through my dissertation. I leaned on you for guidance and direction at various points in the project. Your time, expertise, detailed feedback, and genuine care for my success amplified my project to a level I could not have reached on my own. Thank you for your unparalleled direction to reach this level of my academic career. To Dr. Barnicle, from my core, I want to say thank you for believing in me as your doctoral student. I would not be in this position today if it wasn’t for you and I know you were always in my corner. Certainly being admitted into this PhD program took a few attempts, but you gave me the opportunity to pursue my Ph.D. as your graduate student in the program, something that was absolutely outside of my control. I still remember receiving a phone call from you as I was walking through the lobby of the University of Utah hospital, offering me a place to work with you at West Virginia University. It was a memorable moment for me. I have learned many things from you, specifically the power of networking, building relationships, and the value of reversed planning to establish realistic goals with the end in mind. But most of all, your openness as a mentor has always helped me see the bigger picture and truly hunt for the good stuff. Thank you for believing in me and giving me the opportunity to make this dream become a reality. Once you opened the door, it was up to me to make it happen. To Dr. Watson, “The Giant” and legend of WVU SEP. As if by fate, I was very lucky to have you as my second mentor at WVU. I thought that the ship had sailed, but miraculously, I was able to receive your mentorship within a short period of time. You encouraged me to become a more effective researcher and consultant, assessing my perceptions and goals as a practitioner. You trusted in my abilities to succeed and gave me vital counsel that I needed at just the right iv time. You surgically analyzed my qualifying project redundancy, putting it in the place where it needed to be. I am very grateful for your mentorship and thoughtful advice throughout my time at WVU. Thank you for everything you helped me achieve. To Dr. Houlihan, Dr. Kampoff, and Dr. McAlarnen, you all showed me how to lean into research and acclimatize to the research grind. I can recall your advice that a masters thesis is similar to a “campfire” whereas the dissertation would be a “firestorm”. Fortunately, my masters thesis resembled more of a firestorm and prepared me for what was to come. At every turn, each of you played a critical role in my development as a researcher and consultant, providing me with many opportunities to grow. My heartfelt gratitude extends to you for your mentorship and instrumental influence in my work and personal growth. To my research team, Natalie, Alex W., Alex M., Adonté, Peyton, and Caitlin, I want to genuinely thank you for your dedication, effort, and willingness to work in the research trenches with me. I relied on each one of you on many occasions without much in return. You invested your time and abilities behind the scenes to bring this project into fruition, and each of you responded with great enthusiasm and insight when it was needed. I am forever grateful for your dedication to make this dissertation happen. To my SEP classmates, I am immensely grateful to each of you. Your support throughout this project kept me level-headed and grounded by reading drafts, reviewing slides, and listening to me conceptualize when I needed it the most. Specifically, my basecamp desk neighbors Lindsey and Hannah, thank you for your positivity and friendship. To my cohort, Kim, Diane, Suzanne, and Chip: My experience at WVU would not have been the same without you. I am grateful for your genuine friendship and memories that we built together these last few years. Our tight knit group and devotion to one another has been an enormous blessing, one that I know will continue to grow beyond WVU. You all mean so much to me, and it is an honor to be a part of the 2020 team. To my program mentor, Kevin, you sir have been my go-to “mountaineer guide” from my first interview week in 2019 crashing at your place to my dissertation completion. I am exceptionally grateful for your sincere care for me and my family from day one, making our years at WVU unforgettable. To Mom and Dad, your lifelong lessons continue to guide me wherever I go, in each endeavor I face. Your influence on me is immeasurable and I am grateful to be your son. You have taught me how to observe and serve (“seeing the need”), show kindness to all, uphold my integrity wherever I find myself, follow through with commitments, and embrace a deep love of work. With many more essential skills needed to lead a fulfilling life, you’ve equipped me with the ones required to enjoy and conquer challenges along the way. I love you both! To my siblings and in-laws: Over the last decade, you have all supported our academic journey across the country in different ways and provided guidance throughout. I have benefited greatly from your advice and wisdom (drawn from many movie quotes) in seeing what lies ahead. I am very blessed to have each one of you and your constant support, knowing that I can always turn to you for help. Everything is mucho nice! v To my boys, Jagger and Zane, you bring insurmountable joy and energy to my life. Being a father to you is unquestionably the greatest blessing I have and the most important role I have on this earth. Each day, you were my alarm clock, my morning sendoffs, my escape from the academic marathon, and my greeting party when I walked through the front door. Good days or bad, you both brought me a significant amount of joy that pushed me through the hardest of nights. Many ideas flowed as I’d rock you to sleep, and the dedication to see this project through came from your energy and smiling faces. To Lacey my words here cannot fully describe how much you mean to me and the love I have for you. You are my anchor, my harbor from the storm, my oasis amid the many moments of struggle in receiving this foundational accomplishment. Your unwavering support, love, and encouragement during all the breakthroughs and setbacks were significant sources of strength for me and I couldn’t have done any of this without you by my side. No doubt, balancing the demands of a decade-long grad school journey with the joys and challenges of raising our kids has been no small feat, yet we’ve grown together in more ways than I thought possible. Many early mornings, late nights, and sacrifices were given to see this through. You gave me the time and inspiration needed to achieve this goal. I am forever grateful to you and what we did together. I see this achievement is as much yours as it is mine. I love you! Above all, I am thankful for my Heavenly Father and Jesus Christ, who shaped me into the man I am today. They continue to provide me with significant comfort and peace in everything I do. With all of my inadequacies and limitations, I undoubtedly know that God has lifted me up in every moment under His watchful care. He knew where I needed to be and recognized that the many setbacks and disappointments leading up to this point provided me with a richer, more fulfilling experience in West Virginia. He renews my soul day-in and day-out and influences my life to transcend beyond my own capabilities. With Him guiding me, I am ready for the journey forward, confident that I will continue to learn and grow, just as a skilled rider learns to navigate new terrains. More is to come, and with each new challenge, I trust that He will be with me, securing my hands to the reins and guiding my steps no matter what unforeseeable horizon lies ahead. “I do not boast in my own strength, nor in my own wisdom; but behold, my joy is full, yea, my heart is brim with joy, and I will rejoice in my God. Yea, I know that I am nothing; as to my strength I am weak; therefore I will not boast of myself, but I will boast of my God, for in his strength I can do all things.” – Alma 26:11-12 vi Table of Contents Examining the Online Marketing of Sport Psychology Services by Certified Mental Performance Consultants: A Rhetorical Analysis.................................................................................................................1 Perceptions of Sport Psychology Services................................................................................................2 Online Marketing of Sport Psychology Services......................................................................................4 Persuasion and Online Marketing .............................................................................................................6 Significance...............................................................................................................................................8 Method ................................................................................................................................................................9 Research Design........................................................................................................................................9 Participants................................................................................................................................................9 Procedures............................................................................................................................................... 10 Coding and Agreement Procedure .......................................................................................................... 14 Data Analysis.......................................................................................................................................... 15 Results ...............................................................................................................................................................16 Demographics ......................................................................................................................................... 16 Online Platform Use................................................................................................................................ 17 Persuasive Elements................................................................................................................................ 17 Relationship Between Persuasive Elements and Demographic Factors ................................................. 18 Rhetorical Examples............................................................................................................................... 19 Discussion..........................................................................................................................................................22 Key Findings........................................................................................................................................... 23 Demographic Differences in CMPC Profiles of Persuasion ................................................................... 27 Limitations.............................................................................................................................................. 28 Future Directions .................................................................................................................................... 29 References.........................................................................................................................................................31 Appendix A.......................................................................................................................................................39 vii Appendix B .......................................................................................................................................................41 Tables.................................................................................................................................................................42 Extended Review of the Literature.................................................................................................................50 Receptivity and Perceptions of Sport Psychology Services.................................................................... 51 Online Marketing .................................................................................................................................... 53 Obstacles to CMPC Marketing ............................................................................................................... 55 Persuasion ............................................................................................................................................... 58 The Elevator Pitch................................................................................................................................... 60 Conclusion .............................................................................................................................................. 68 Extended References .......................................................................................................................................70 CMPC PERSUASION 1 Examining the Online Marketing of Sport Psychology Services by Certified Mental Performance Consultants: A Rhetorical Analysis Athletes, coaches, and athletic trainers increasingly use technological tools to amplify athlete effectiveness (Giblin et al., 2016) including virtual reality systems (Bird, 2020), wearable devices (Seshadri et al., 2019), and biofeedback training models (Dupee et al., 2016). Alongside these advancements in performance technology, the use of social media among athletes has also increased dramatically. Researchers recently found that student athletes interacted with their smartphones 4.5 hours per day (DesClouds et al., 2018). A follow-up study found that 81% of athletes interviewed had their smartphone nearby continually, largely used for social media, communication, and organization tasks (DesClouds et al., 2021). Not surprisingly, coaches and other sport personnel including Certified Mental Performance Consultants (CMPC) have noticed this rise in mobile device use among athletes in the locker room and off the playing field where athletes use these devices to develop relationships, distract oneself from sport pressures, or search for strategies to better prepare the athlete for performance. Encel et al. (2017) added to this trend showing that 68% of 300 British athletes checked their social media accounts within two hours of competition. Real life examples of athletes using social media to prepare for performance include gold medalists Simone Biles, Michael Phelps, and NBA champion Kevin Love. These athletes have used online platforms to openly talk about their psychological struggles to normalize mental health and mental performance training. In addition, “Mind Health” (NBA), “Player Health and Safety” (NFL), “Unmind” (MLB), and the “NHL Player Assistance Program” were created to provide greater physical and psychological well-being to athletes on devices (Jia et al., 2022). Sport psychology consultants (SPCs) have become aware of these transformations within the sport environment on the digital front, particularly with the CMPC PERSUASION 2 introduction and implication of smartphone apps. The literature notes that sport psychology apps have been around for nearly 20 years (Cotterill & Symes, 2014; Prior, 2014), and the use of such apps have been linked with improved mental skills. For instance, Stenzel and colleagues (2021) found significant increases in concentration and self-efficacy, and more frequent recovery after implementing a sport psychology app intervention to 44 athletes. SPCs have taken note of these influences at play, particularly after the Covid-19 pandemic (Gretton et al., 2022) as it provided opportunities for SPCs to reach more athletes virtually. Social media has also facilitated the messaging and broadcasting of sport psychology services to the consumer, making mental skills training more accessible. It is possible that the expanded use of technology in sport psychology has reduced the stigma of mental health and increased awareness of mental health and performance issues. It is not surprising that consulting work—once a face-to-face endeavor—has now turned into a hybrid arrangement where inperson or remote consultations co-exist (Cotterill & Symes, 2014). Using these asynchronous methods, SPCs are then tasked with communicating their messages to potential consumers interested in sport psychology services and maintain the connection to benefit the athlete’s overall play. Perceptions of Sport Psychology Services Research shows that most sport personnel (e.g., athletes, coaches, athletic directors, athletic trainers, strength and conditioning coaches) have a positive outlook on sport psychology (SP) services (Fortin-Guichard et al., 2018), particularly when services improve athlete performance and when sport psychology consultants (SPCs) have strong interpersonal skills to connect with others. One study showed that coaches were receptive to sport psychology providers who developed trust in the consultant and believed the SPC was a beneficial asset to CMPC PERSUASION 3 the team (Sheehy et al., 2019). This feeling of trust was corroborated by other studies showing that trust is a strong element of persuasion within interpersonal relationships (Farhat et al., 2022; Isai et al., 2020). There are several SPC characteristics that influence perceptions and decision-making when choosing a SPC. A recent systematic review by Woolway and Harwood (2020) analyzed 17 studies totaling 2962 participants to determine what SPC characteristics affected participant perceptions and decision-making when choosing a SPC. They reported that athletes preferred having SPCs with similar physical and demographic characteristics to them (e.g., age, gender, physical appearance). In addition, interpersonal skills and accreditation were shown to be important characteristics as well. Such findings resembled Lubker et al.’s (2008) study supporting the idea that college athletes and SPCs preferred similar characteristics (e.g., sport culture, sport knowledge, and athletic background) in consultation practices. Similarly, researchers have sought to gain an understanding of what sport psychology consultants do to attract and maintain clients from different sports, motives, and age groups. In one study, researchers found that college athletes (n = 464) preferred consultants with an advanced degree and refined interpersonal skills (Lubker et al., 2012). Moreover, being an expert, showing genuine care for athletes, and having a strong knowledge base of the sport (e.g., terms, rules, and jargon) increased a consultant’s perceived value in this study. Another systematic review explored stakeholder perceptions of SPC characteristics by analyzing 33 qualitative-focused articles (Tod et al., 2022). These researchers found that the stakeholders wanted SPCs to build strong rapport, display “realness,” instill hope, set expectations, promote client change, and be able to operate well in the client’s location. These CMPC PERSUASION 4 findings provide insight into what athletes and coaches expect to see in an effective SPC and can be used to further advance the field, particularly through technological means. Online Marketing of Sport Psychology Services In the last decade, social media platforms have emerged as the go-to places for online engagement and communication, enabling individuals to interact easily with each other (Adeola et al., 2020). Marketers and advertisers have taken advantage of this concept to promote their products; however, little evidence shows how Certified Mental Performance Consultants (CMPC) use online platforms to connect and promote their brand to meet the needs of the consumer. Baxter and Smith (2017) explained this lack of marketing ability and recommended that CMPCs implement two forms of marketing to promote their services by implementing active and passive marketing. Active marketing focuses on establishing direct contact with potential clientele by leveraging existing relationships, direct messaging, cold calling, and networking at specific events. Passive marketing suggests building a reputation where potential clients contact the consultant based on word of mouth, referrals, and advertisements. Within these strategies, Baxter and Smith (2017) encouraged SPCs to create a professional website to educate individuals about sport psychology and their expertise to establish authenticity with the potential buyer. The Association for Applied Sport Psychology (AASP) has also provided an online platform for potential clients to connect with consultants to connect with the general public in their local area, but no data exists if the general public uses this website to find consultants (AASP, 2023a). Data publicly available through the Association for Applied Sport Psychology, may fill this gap for certified SPCs, but dissemination of this information is limited within the marketing framework. Despite Baxter and Smith’s (2017) recommendations, Waite and colleagues (2021) affirmed the need for better marketing strategies in their study when examining Olympic track and field CMPC PERSUASION 5 athletes, many of whom were unfamiliar with sport psychology services and accessibility. These authors acknowledged that an online consultant profile would help address the limited knowledge consumers have about SP and establish a means of communication among the athletes. Participants within this study suggested that embracing different online forms of communication would be helpful for both parties (i.e., the consultant and the athlete), especially if the website included the CMPCs bio, sport knowledge and background, and contact information for obtaining services. Such an approach may clear an athlete’s unfamiliarity with the services provided, as different platforms have different ways to deliver SPC messages. Specifically, a study analyzing how the Twitter platform is used to communicate with athletes and other practitioners found that the content of SPC tweets focused on media comments (e.g., TV programs, news stories), advice and opinion, thoughts on events, self-promotion, knowledge dissemination, and lifestyle (Cotterill, 2022). CMPCs identified that social media presence had a positive impact on their work based on feedback from others. More than 60% of the SPCs used a professional social media account to connect with athletes, yet surprisingly, more than half (52%) did not engage in professional conversations on the platform. Some professionals indicated they felt unskilled at using social media most effectively or feared of putting themselves at risk in terms of privacy and not being aligned with ethical standards provided by their governing body (e.g., AASP, BASES). Cotterill (2022) indicated that SPCs expressed a desire to deliver information of value to alter thinking or behavior—a distinctive characteristic of persuasion. Research has yet to explore how CMPCs are intentionally attempting to educate or persuade potential clients in a particular way. Therefore, it would be beneficial to examine the elements of persuasion and how these elements show up in SPC work. CMPC PERSUASION 6 To better understand how SPCs use online marketing, theories of persuasion can be applied to identify ways SP services are being delivered. Other research analyzed the engagement of SPCs on social media to find it if was a consultant to understand their perceptions of professional use of social media (Cotterill, 2022). The findings showed that more than 60% of SPCs used a professional social media account to connect with athletes, but 52% did not engage in professional conversations on the social media platform. The professionals in the study cited several factors limiting their engagement, including, a lack of social media competency, a fear of putting themselves at risk, and not being aligned with ethical standards. Research has yet to explore how CMPCs intentionally attempt to bridge the gap, and for that reason, it would be beneficial to examine the persuasive strategies used in online platforms of credentialed sport psychology professionals. Persuasion and Online Marketing Persuasive communication is used online to influence their decision-making process (Hong et al., 2020). Descriptive elements, shown through Rhetorical Theory, help explain the content of what is taking place, why the persuader chooses specific language to convey a message, and how such choices influence people. Three important markers of persuasion are regularly explained in scientific literature to influence people, which include ethos, pathos, and logos that appeal to persuading someone in a certain way (Leach, 2000). Ethos arguments appeal to the credibility or trustworthiness of the source, whether the message is delivered from an expert or reliable source. Pathos-based arguments use emotions to stir up a response and logos appeals to logic, whether it is real or perceived, to convey a specific convincing message. One sport psychology study addressed the principles above in outlining a persuasive elevator pitch by describing a rhetorical scenario. In his example, Simpson (2016) explained that a SPC may write CMPC PERSUASION 7 a persuasive message by integrating specific examples of ethos, pathos, and logos in brief marketing form to give practitioners a starting point for marketing their services. However, this publication was not data-based but rather a commentary offering a practical solution for young professionals to improve their marketing. Embedded underneath these three elements that promote good rhetorical positioning, statis theory and the five canons of rhetoric (e.g., invention, arrangement, style, memory, and delivery) are described as important drivers in viable persuasive communication (Leach, 2000). Statis theory is a rhetorical method that helps decide what is the point of a persuasive message, position, and effort to bring people with various opinions to a state of agreeableness or stability. Statis theory uses reflective questions to gather the facts, definitions, quality (good/bad/fair/unfair), and actions to examine what each person thinks about a specific issue (Carter, 1988). The five canons of rhetoric begin with invention, which is the act of brainstorming the message which leads to arrangement or the process of deciding how the content will be organized. Next, style is used to demonstrate how the words will be incorporated through tone, pace, and word choice. Style may also integrate metaphors and analogies to amplify description. Memory indicates the process of committing a certain topic to memory to draw upon when needed and delivery is the action of presenting a message to an audience. Although research in sport psychology has not evaluated consultant marketing directly through the lens of ethos, pathos, and logos, other fields have examined such rhetorical elements in online settings. A recent study found that all three persuasive appeals were used in higher education recruitment websites to influence students and parents (Oeppen Hill, 2020), particularly ethos which was extensively used. Research in business has focused on the importance of persuasion, much of it rooted in the work of Cialdini (2001) who identified six CMPC PERSUASION 8 principles of persuasion that can be connected to online influences—reciprocity, consistency, social proof, authority, liking, and scarcity. To provide context, reciprocity suggests that people are instinctively drawn towards returning favors. An example would be a CMPC offering a 10% discount or free handout when a consumer subscribes to their webpage. Next, people are persuaded by consistency and stability. A CMPC following through with their commitments or keeping promises are examples of consistency. Social proof means that people follow what others do. For instance, persuasion comes from sharing testimonials from successful athletes, coaches, or athletic directors elevated credibility. Exposure to positive testimonials can be associated with greater intentions to use cognitive services (Apolinário-Hagen et al., 2021). Persuasion is increased when paired with authority, specifically represented through an earned credential or graduate degrees or licenses. Next, people are persuaded by things they like. Therefore, liking sport psychology or having a shared interest by the way a CMPC applies mental skills can fortify a consumer buy-in, especially if this service is perceived to be popular or used by athletes they know. Lastly, people are persuaded to act when they believe resources are scarce. In online marketing, CMPCs can use messages to project scarcity by using phrases such as “limited time offers” or “two spots left on webinar” to urge consumers to make decisions. Significance No research to date has explored how CMPCs use these persuasive messaging strategies that stem from Leach (2000) and Cialdini (2001) in the online marketing space. Many CMPCs use social media to educate consumers and to promote their services, but little research has explored the quality of its content. The purpose of this study is to evaluate the persuasive messaging of online content created by Certified Mental Performance Consultants to attract CMPC PERSUASION 9 potential clientele. Social media platforms and professional websites provide a virtual tool for consultants to showcase their work and promote the field of sport and performance psychology to others. • Research Question 1: What online platforms are most used by CMPCs to attract potential consumers to sport psychology services? • Research Question 2: What are the persuasive components that CMPCs use to promote their messaging of sport psychology services? Method Research Design This descriptive study used a Rhetorical Analysis to assess the persuasive features and strategies of language used by CMPCs to market their sport psychology services. Researchers implemented this approach to capture key persuasive concepts (i.e., ethos, pathos, and logos; Leach, 2000) and Cialdini’s (2001) principles of persuasion (e.g., reciprocity, consistency, social proof, authority, liking, and scarcity) to understand what persuasive components are found in CMPC online messaging. These persuasive elements included reciprocity, consistency, social proof, authority, liking, and scarcity. Participants Certified Mental Performance Consultants (CMPCs) were selected as the target population of this study as this is the most widely recognized North American credential in the sport psychology field. A list of CMPCs was drawn from the Association for Applied Sport Psychology (AASP) organizational website representing 1004 active CMPCs (as of December 2023). Under the AASP standard, a CMPC must obtain formal education and at least 400 hours of mentored experience, pass a standardized certification exam, and receive a formal board CMPC PERSUASION 10 review (AASP, 2023a). Publicly available data on the AASP “Find a Consultant” interface was used to compile the list of CMPCs in this study and record demographic and social media information for each individual consultant. Procedures Since the data in this study was contained on public websites, no Institutional Review Board (IRB) approval was necessary. Procedures were conducted in three phases to identify eligibility, demographics, and persuasive strategies found. Phase I – Identifying Eligible CMPCs & Available Social Media Profiles In Phase I, the researchers collected all CMPC profiles (n = 1004), demographic information, and social media accounts registered under each CMPC profile using the “Find a CMPC” icon. These CMPC profiles were added to a cloud-based spreadsheet for easy access and research team collaboration. The social media platforms recorded included the consultants: 1) professional webpage; 2) LinkedIn; 3) Facebook; 4) Twitter/X; and 5) Instagram. Research team members were selected and trained individually by the lead researcher on how to enter these different platforms and record specific information within the CMPC profile such as: 1) year certified (1992, 1993, ... 2023), 2) level of education (master’s degree/ doctoral degree), and 3) licensed counselor or psychologist (Yes/No). This task helped determine the overall scope and range of professionals in the CMPC population. Gender identity was not available in the AASP CMPC profile, and therefore was not captured. Phase II – Descriptive Analysis of CMPC Demographics & Profile Eligibility The aim of Phase II was to discover what online platforms were most used by CMPCs to attract potential consumers to sport psychology services and identify a subsample of CMPCs to more closely examine their persuasive approach in marketing their services. This process CMPC PERSUASION 11 revealed that the professional website (n = 388) and LinkedIn (n = 408) online platforms were the two most used platforms among CMPCs. To narrow the complexity of examining all five online platforms, the decision was made to explore consultants in possession of both a professional website and LinkedIn account as the focus of the rhetorical analysis for Phase III. This decision reduced the target CMPC population to 219 consultants. Phase III – Rhetorical Analysis of Content The goal of Phase III was to analyze the persuasive elements found in the selected CMPCs (n = 219) professional websites and LinkedIn profiles. The written content found in the professional websites were copied from each main webpage and service-related tabs (e.g., ‘Home’, ‘Services’, ‘About’, ‘Our Team’, etc.) onto an Excel spreadsheet. These website tabs were selected because they represented the CMPCs marketing structure and style in how they described who they were, what they do, and how sport psychology services will benefit their consumers. Other professional website text promoting CMPC services was also captured including testimonials, customer reviews, subscriptions, discounts, and free material for purposes of identifying persuasive material. Next, the LinkedIn content captured for each CMPC contained information in the “About” section, number of “Active Followers”, the consultants highest “Education” level (master’s/doctorate), and evidence of being a licensed/psychologist found in the “Licenses & Certifications” section. The collection of written content from these two platforms was performed solely by the lead researcher to minimize research team mistakes and establish a standard database for the research team to code. Following the data extraction from the professional websites and LinkedIn profiles, the lead researcher created a persuasion codebook based on Leach’s (2000) Rhetorical Analysis principles and Cialdini’s (2001) Six CMPC PERSUASION 12 Principles of Persuasion to train and guide the research team during the coding process (see Appendix A). Training the Research Team. Four college-level undergraduate research team members were recruited and trained using the Persuasion Codebook (Appendix A) and the Persuasion Codebook Checklist (Appendix B) during several in-person training sessions. Next, ten practice CMPC profiles were purposefully selected and distributed among the team members (e.g., lead researcher and four research team members) to code. The first two CMPCs were coded collectively and then the remaining eight were coded individually to establish an operational baseline for coding comprehension among team members. Specifically, the team navigated the Excel spreadsheet for all written content previously extracted, then after, entered the two online platforms to record subtle persuasive instances that would appear on the website such as subscription buttons, testimonial paragraphs, free materials, and automatic pop-up discounts for other persuasive elements. The lead researcher personally reviewed the initial ten CMPCs collected by the research team. After this first step, the research team met to address data troubleshooting, coding discrepancies, and volume of subtle persuasive element differences. These meetings led to a revision of the Persuasion Codebook to help clarify definitions, locate areas on the online platforms rich with content, and specify how multiple testimonials, customer reviews, and subscription invitations would be counted. Clarifications were made regarding the concepts of Ethos vs. Authority and Pathos vs. Liking as they were identified as problematic due to the difficulty distinguishing these persuasive elements from one another. For instance, to differentiate ethos and authority, team members categorized these elements based on the specific time where the credibility of ethos represented a past form of credibility and authority represented a present form of credibility. Specifically, ethos statements were identified as a past CMPC PERSUASION 13 form of credibility as described through years of experience, former accolades (e.g., “national champion”, “best-selling author”), high quality sport resume (e.g., “former Olympian, college athlete, or coach”), or expertise in a specific research area. Authority statements were identified as a present form of credibility based on the consultant’s current educational or employment status (e.g., PhD, CMPC, CEO, licensed psychologist) or official title (e.g., “Dr. _____”, “Director of Mental Performance”, “Associate professor”). In the case of Pathos and Liking, pathos was identified as an emotional phrase used to draw out emotion in people. Examples included statements such as “dream big” or “chase your goals”. Liking was identified as a shared interest by the CMPC to seem more human (e.g., “My first love was basketball”, “We’re in this together”, “I’m passionate about building a strong mind”). It was noted that coders were not to decide whether the message appealed to their personal emotions or shared interest but coded based on the CMPCs attempt to connect to a potential client through their messaging. Critical dialogue during these meetings clarified such persuasion elements and provided transparency throughout the data collection process. After examining the initial ten CMPCs and adjusting the Persuasion Codebook, the lead researcher selected one model CMPC profile with numerous persuasive strategies to teach and demonstrate a good example of where to find persuasive elements, what to count and not to count, and how messages can be interpreted in the foreseeable online platforms. Once understood and thoroughly reviewed by the team, ten more profiles were selected and distributed to evaluate the persuasive elements and the coders’ proficiency after revising the Persuasive Codebook. Two profiles were coded as a group to identify any remaining coding discrepancies and clarity of persuasive elements. Once the team agreed, each team member coded eight CMPCs individually and areas of uncertainty were resolved by the research team until the coding CMPC PERSUASION 14 results reached conformity. No revisions to the Persuasion Codebook were made after the 21st CMPC was coded, representative of the ten percent CMPC sub-sample. Lastly, the development of a rating system was established to maintain inter-rater reliability for each persuasive element. The inter-rater reliability for the first 21 CMPCs followed the agreement of four coders and finally the lead researcher as the final coder. For example, the identification of a persuasive element in a CMPC profile was agreed upon when at least 3 of 4 coders would agree (75% agreement or better) determined it existed in a specific message (Cohen, 1968; Hemmler et al., 2022). When coders reached a split consensus suggesting 2 of 4 coders agreed, the lead researcher would act as the final coder to override the presence (or absence) of the persuasive element. This logic remained consistent throughout the training coding process but was slightly modified when the research team was split into pairs to code the remaining CMPCs. Coding and Agreement Procedure The lead researcher separated the four-person research team into two pairs to analyze the remaining sub-sample of CMPCs (n = 198), thus creating a double coding process for each profile. Each pair was assigned to code half of the remaining CMPC profiles (n = 99) individually to cross check the presence of persuasive elements, reduce bias, minimize coding fatigue, and ensure data entry was consistent. The lead researcher coded all 198 CMPCs to establish a master code index used to override any disagreements when necessary. An agreement/disagreement procedure was formed to report persuasive elements that appeared in the CMPC profiles. Specifically in pairs, when the code of both team members aligned, shown by 2 Yes’s or 2 No’s, the persuasive element was marked “present” or “not present” in the spreadsheet. This uniformity between the two coders overruled the lead researcher’s master code CMPC PERSUASION 15 even if the lead researcher identified the opposite code of the specified persuasive element. When the team members split with 1 Yes and 1 No, the master code index of the lead researcher consequently resolved the discrepancy in the direction of the lead researcher’s code. The completion of coding 198 CMPCs by the research team yielded a total of 3564 decisions made per research team member (post-training) with 455 decisions being resolved by the lead researcher. Calculated from the mean, an agreement rating was reached by the research team at 87.24%, suggesting that 12.76% of the decisions were resolved by the lead researcher based on definitions within the code book. Furthermore, the research team agreement on each element indicated the following: ethos (78.5%), pathos (78.0%), logos (89.9%), reciprocity (94.7%), commitment/consistency (86.9%), social proof (89.4%), authority (89.4%), liking (84.8%), and scarcity (99%). Data Analysis To answer research question one, the descriptive statistics found in Phase I and Phase II were calculated from the total population of CMPCs (n = 1004) to measure what percentage of CMPCs used the specific five online social media platforms. At this stage, the researcher calculated the mean and standard deviation in “years since certification” for the entire sample, and the percentage of the overall sample with an MA//MSW/MEd/MS (“master’s”) vs. PsyD/PhD/EdD (“doctoral”) degree. These demographic analyses were repeated in the subsample of CMPCs profiles in the rhetorical analysis. To answer research question two, the researcher presented summary data on the percentage of profiles that contained each of the nine persuasive elements, and the mean number of instances of each element for the entire sub-sample. This portion of the analysis provided an overview of the most common persuasive elements present in the written content provided by the CMPC PERSUASION 16 CMPCs. Example quotes connected to each of the persuasive elements were highlighted showing the most common ways that CMPCs attempted to persuade clients to use their services on these two platforms. Within these examples, the research team made attempts to represent the diverse ways that CMPCs used each persuasive element. As this study was exploratory, the lead researcher examined the relationship with three demographic variables collected (years since certification, level of education, and licensed/psychologist status “yes/no”) and the presence or absence of each persuasive element. To address the connection with years since certification, independent t-tests were conducted by analyzing each persuasive component individually, with each persuasive element (as the Independent Variable) and the mean years certified (as the Dependent Variable). Data was checked for normality and equal variances prior to conducting the analyses, and Cohen’s d was calculated to show the effect size for each mean comparison. To investigate if each persuasive component was associated with level of education (Master’s vs. Doctoral) and Licensure (Yes/No), a chi-square (two-way) test of independence was performed separately for each of the nine persuasive components (present or absent). Results Demographics Of the 219 CMPCs examined in Phase III, 89 (40.6%) were master’s level CMPCs and 130 (59.4%) were doctoral level CMPCs. Between 2019-2023, 69 (31.5%) were master’s level CMPCs and 62 (28.3%) were doctoral level CMPCs. Fifty-five (25.1%) CMPCs were clinically licensed or designated psychologists with 29 (52.7%) of 55 CMPCs obtaining CMPC status since 2019. The level of education combined with licensure indicated that 15 (16.9%) master’s level CMPCs obtained clinical licensure and 40 (30.8%) doctoral level CMPCs had clinical licensure. CMPC PERSUASION 17 What stands out in this finding shows that doctoral level CMPCs are nearly twice as likely to be licensed compared to master’s level CMPCs with the presence of LinkedIn and a professional website. Moving to years since certification, the Phase I data of 1004 CMPCs demonstrated that the acquisition of the CMPC credential had increased within the last decade (M = 4.63, SD = 5.84) with 667 (66.4%) new CMPCs from 2019 to 2023. Based on the AASP CMPC country of origin, 846 (84.3%) were listed from the United States, 103 (10.3%) from Canada, and 55 (5.5%) from other countries. Online Platform Use Approximately 2/3 (64.2%) of all active CMPCs had at least one form of social media platform connected to their profile, with LinkedIn (40.6%) and professional website (38.6%) as the most common forms of marketing of services. Instagram (13.4%) and Facebook (11%) covered the least amount of use in terms of sport psychology online marketing whereas Twitter (X) accounted for 205 (20.4%) CMPCs. Within the last five years of the total CMPCs being certified, 270 (26.8%) had LinkedIn, 223 (22.2%) had a professional website, 97 (9.6%) had Twitter (X), 97 (9.6%) had Instagram, and 60 (5.9%) had Facebook. On average, the number of LinkedIn followers of the overall sample was 440 followers per CMPC and the subsample was 1319 followers per CMPC. Persuasive Elements Overall, the study generated several findings that indicated CMPCs attempting to be persuasive in their online written content, intentionally or not. First, the CMPCs appeal to credibility and expertise was identified as the most common form of persuasion with ethos appearing in 82.6% of the profiles (M = 0.83, SD = .379) and authority appearing in 83.6% of the profiles (M = 0.84, SD = .371). Authority was often represented by the CMPC including their CMPC PERSUASION 18 credentials (e.g., PhD, CMPC, PsyD, etc.) and current job status, whereas ethos represented years of experience in the field and former areas of credibility. Second, pathos was represented in 72.1% of the profiles (M = 0.72, SD = .449), marking emotional appeal as a common persuasive element used, with liking shown to be present in 37% of the profiles (M = 0.37, SD = 0.483). Third, social proof was associated with client recommendations and past service experiences, such as testimonials and customer reviews. Social proof appeared in 30.1% of the profiles (M = 0.30, SD = .459). Fourth, commitment/consistency was found within 29.7% of profiles (M = 0.30, SD = .457) with persuasive elements created to keep potential consumers engaged on their professional website or LinkedIn. Fifth, reciprocity, or the exchange of CMPC resources for consumer engagement (e.g., discounts, deals, free materials), appeared in 26% (M = 0.26, SD = .439) of profiles. Consultants offering a free initial consultation was the most common strategy observed. Logos and scarcity were the least used persuasive elements with 8.7% (M = 0.87, SD = .282) and 0% respectively. Table 1 provides the results obtained from the analysis of persuasive elements. Relationship Between Persuasive Elements and Demographic Factors Independent samples t-tests and chi-squared analyses were conducted to examine potential differences between persuasive elements and demographic factors. Prior to the t-tests, years since certification was assessed for normality and skewness, and the data were non-normal (skewnessz = 7.87; kurtosisz = 4.13). Due to this violation of normality, the non-parametric equivalent tests were run for each element (Mann-Whitney U). These analyses showed no significant difference in the years since certification and the presence of any rhetorical element. There were some interesting patterns with logos and reciprocity data, however, large variability (error) obscured the potential for statistical significance. Table 2 shows an overview of these CMPC PERSUASION 19 results. Chi-squared tests were performed to examine if there was a significant relationship between the CMPCs level of education (Master’s vs. Doctoral) and licensure status (yes and no) with the nine persuasive elements. The results indicated four persuasive elements were associated with one of these variables with small effects. For instance, there was a significant small effect for reciprocity with level of education (χ2(n = 219, df = 1) = 4.59, p = 0.032, φ = .145). Those with Master’s degrees were more likely to have reciprocity within their marketing. Furthermore, there was a small effect for social proof with level of education (χ2(n = 219, df = 1) = 5.64, p = 0.031, φ = .145) suggesting that those with Master’s degrees were more likely to have elements of social proof throughout their online platforms. Next, there was a small significant effect for both authority with licensure (χ2(n = 219, df = 1) = 5.48, p = 0.034, φ = .143), and social proof with licensure (χ2(n = 219, df = 1) = 5.64, p = 0.026, φ = .151). These findings indicated that CMPCs who were licensed were more likely to show elements of authority but not social proof in their online content. There were other persuasive elements that were interesting but were not shown to be significant. The summary statistics for this data between persuasive statistics and licensure are stated in table 3 and table 4. Rhetorical Examples The research team identified qualitative examples of each persuasive element generated from the CMPC professional website and LinkedIn. The examples were drawn verbatim from the CMPC profiles. Such content was coded as an attempt made by the CMPC to persuade their services toward prospective clientele and not assessed based on the effectiveness of each message. Ethos: The appeal of credibility, trust, character, and reputation of a skilled expert. CMPC PERSUASION 20 Example 1. “A dynamic speaker and expert steeped in the science of human performance, she works with Fortune 500 companies, accomplished athletes, organizational leaders, and anyone else striving to achieve their greatest ambitions.” Example 2. “Utilizing research-tested techniques and technology to boost performance for athletes, performers, and business professionals at all levels, I have worked in the sport and performance field as a coach, educator, trainer, athlete, and consultant for more than 20 years.” Pathos: The appeal of emotions, values, and imagination of the listener. Example 1. “What mountains are you currently climbing? Whether it's the corporate or athletic field, the biggest battle we have is the one against ourselves. I help people get out of their own way and conquer their own personal mountain. Well, I am here to say that LIFE and SPORT don't have to feel like such a grind! YOU can take ACTION and get back to what matters most. It’s not a lack of talent, skill, or will that keep people from reaching their true potential. It’s a failure to understand and align all the factors—mental, physical, emotional, and psychological—that underpin true excellence.” Example 2. “You're an athlete. We know you're dedicated, and we know you're committed to being your best. We also know that no two athletes are the same. From your training regimen to the tradeoffs you make, to the pressures and expectations that surround you—this is your unique journey to become the best athlete you can be. Our mission is simple— to help every athlete take their performance to the next level.” Logos: The appeal of reason, order, and logic toward the listener. Example 1. “Here are some general statistics on sport psychology therapy: 34-45% Elite athletes experiencing mental health challenges. [2016 journal article cited], 10-20% Athletes experiencing symptoms of burnout during their career. [2004 journal article cited], 50% NCAA CMPC PERSUASION 21 athletes that feel comfortable seeking support from a licensed mental health provider on campus. [2023 journal article cited] 65-75%, Athletes experiencing psychological distress during injury rehabilitation. [Brewer, B. W., & Petrie, T. A. (2014)]” Reciprocity: A self-imposed sentiment that people feel instinctively drawn towards returning favors or repaying obligations as a means to restore balance. Example 1. “I’m offering a free 30-minute phone consultation to give you an opportunity to speak with me to get a sense of my approach.” Commitment/Consistency: A persuasive strategy used to encourage prolonged engagement with a specific behavior that speaks to a person’s values and self-interests. Example 1. “Click here to read more about what Mental Skills Training is and how it can help you perform at your best!” Example 2. “Learn more below or contact a [CMPC] professional to determine the service that is right for you.” Social Proof: People do things that they see other people do and will look for direction and social reinforcement to support that behavior. Example 1. “Dr. [CMPC] showed me a different perspective that was practical and made sense. His approach helped me place at the World Championships and later qualify for the Olympics. I could not have done it without his help!” Example 2. “Dr. [CMPC] was there throughout my college and NFL career and was a big reason I made it to the NFL to live out my dream. He gets players back on track so they can get back to doing what they do best!” Authority: People will follow the lead of credible and knowledgeable experts depending on their initial impression and presence. CMPC PERSUASION 22 Example 1. “I am a licensed psychologist with a Ph.D. in Counseling Psychology.” Example 2. "[CMPC] is the author of the Amazon Best Seller, [book title], an awardwinning speaker and host of the top-rated podcast which has over 2 million+ downloads in more than 120 countries worldwide.” Example 3. “I am Dr. [CMPC], a Clinical and Sport Psychologist licensed in [State 1] (License #), [State 2] (License #), [State 3] (License #), and [State 4] (License #).” Liking: Sharing similar interests and authenticity to engage the listener. Example 1. “Through my own athletic endeavors and roadblocks, I witnessed firsthand how important my own psychology played a role in my ability to compete to my full potential. Whether you are trying to improve your sport performance or are facing any number of personal struggles, I will provide you with compassionate, genuine, and dedicated care.” Scarcity: The belief that certain resources are limited or in short supply which influences the consumer to want services more. Example 1. “[Screen Pop Up]: Please note the [consultant] practice is currently full. We are not accepting new clients until May 2024.” Table 5 depicts more examples of persuasive elements shown in the CMPC subsample. Although this study did not look directly into the number of common phrases used, many profiles did include a form of a mission statement and declaration stating that the CMPC would customize their services based on the needs of the client. Additionally, other common phrases mirror that of, “My practice is grounded in helping people achieve their goals and live meaningful lives” and interpreted through the nine elements of persuasion. Discussion The purpose of this study was to determine the persuasive messaging of CMPCs and their CMPC PERSUASION 23 use of online platforms to attract potential clientele. The findings of this study illustrated that two-thirds of CMPCs had at least one form of social media attached to their AASP profile, most profiles favoring LinkedIn and a professional website platform. Another major finding was that authority, ethos, and pathos were the most prominent persuasive components used in the subsample of CMPCs applying online strategies to market their services. Key Findings In connection with the presence of authority and ethos in CMPC profiles, previous research has highlighted the importance of exhibiting one’s professional status to consumers (Lubker et al., 2012). These persuasive elements were displayed through the CMPCs’ description of their advanced degrees, years of experience, job titles, accreditation and licensure from specific governing organizations, former playing or coaching experiences, and work carried out with well-known teams or athletes in performance environments. The elements of authority and ethos were close in meaning as previously identified by other sources in persuasive literature (Braca & Dondio, 2023; Rabab’ah et al., 2024), often occurring in tandem in a CMPC profile. For instance, a common sentence structure seen throughout many profiles that included authority and ethos resembled the statement: “Dr. Jones is a licensed clinical psychologist [present; authority] with 20 years of experience [past; ethos] working with high performing athletes and teams, specializing in the latest research of mental skills to help individuals reach their potential [past/present]”. Forms of authority and ethos appeared in the same way to support one’s credibility towards its consumers as many profiles showed their professional expertise upfront by using advanced degrees and titles such as “Ph.D., Associate Professor, Certified Mental Performance Consultant, or Owner of [consulting practice] LLC.” These findings of authority and ethos aligned well with other persuasive-centered studies in business, academia, CMPC PERSUASION 24 and cyber security as researchers found that authority and ethos were popular approaches to invoke feelings of trust to a wide range of individuals (Akbar, 2014; Oeppen Hill et al., 2020; Rabab’ah et al., 2024). It is also possible that consultants used authority and ethos in their messaging because they sense that potential clients will view them more favorably. Specifically, researchers have noted that positive impressions can be made w

A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches Diane Benish West Virginia University Follow this and additional works at: https://researchrepository.wvu.edu/etd Part of the Sports Studies Commons Recommended Citation Benish, Diane, "A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches" (2024). Graduate Theses, Dissertations, and Problem Reports. 12442. https://researchrepository.wvu.edu/etd/12442 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact researchrepository@mail.wvu.edu. A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches Diane Benish, M.S., M.A. Dissertation submitted to the College of Applied Human Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Sport, Exercise, and Performance Psychology Sam Zizzi, Ed.D., Chair Ashley Coker-Cranney, PhD. Peter McGahey, Ed.D. Christine Schimmel, Ed.D. School of Sport Sciences Morgantown, West Virginia 2024 Keywords: autonomy-supportive, self-determination theory, coaching, mixed-methods Copyright 2024 Diane Benish Abstract A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches Diane Benish, M.S., M.A. Coach behaviors impact several essential athlete factors such as the quality of athlete motivation and psychological functioning and yet, many youth coaches remain untrained in motivation and athlete-centered principles. This study’s aim was to explore the efficacy of a need-supportive intervention on youth hockey coaches’ attitudes toward, and reported use of, need-supportive and/or need-thwarting approaches. Participants included 25 youth hockey coaches randomly assigned to an intervention or delayed control condition. Grounded in Self Determination Theory, the intervention included four sessions within which coaches learned how to adopt need-supportive coaching strategies and reduce need-thwarting tactics. A mixed methods approach guided the evaluation of the program’s effectiveness via an integration of pre- and post-test measures of coaches’ self-reported coaching style and written reflections. At post test, intervention participants showed significant improvements in self-reported autonomy supportive coaching and significant reductions in controlling and chaotic coaching behaviors when compared with the delayed control group. Coaches reported how program enhancers, barriers, and their implementation efforts contributed to the overall training experience. Overall, the findings indicate that the present intervention approach may be suitable for training other youth sport coaches to adopt need-supportive behaviors and reduce need-thwarting tactics which can enhance youth sport experiences. Acknowledgements iii I am deeply grateful to the individuals who selflessly gave their time to be a part of this project and support my educational journey. Overall, I feel truly blessed to have encountered so many wonderful people during my doctoral studies and I extend my appreciation to those mentors, colleagues, friends, and family members who believed in me and supported my efforts prior to this dissertation. To Dr. Zizzi: Thank you for your incredible mentorship and support. Call it serendipity, but I believe you became my mentor at just the right time. You have truly helped me take ownership of my research and my career. I leave WVU feeling inspired to support and impact youth coaches through my applied work in the years to come and I owe much of that to you for taking a chance on this project. To committee members: Dr. McGahey, the enthusiasm and genuine encouragement you offered me in the early stages of this project fueled my passion and helped me create something special. Dr. Coker-Cranney and Dr. Schimmel, I appreciated your listening ear, counsel, and thoughtful advice as I pursued the perils of data collection and analysis. Thank you all. To Sarah and Holly: Thank you for your efforts in this project and your willingness to join me on this journey. You both have bright futures ahead of you! To my classmates and especially, my cohort, Kim, Jaxson, Suzanne, and Chip: Thank you for your unwavering support, kindness, and genuine friendship. You made my time at WVU truly special and I’m thankful to be in your corner to witness all the wonderful things you have done and surely will do! To my family: Thank you all for your prayers and loving advice as I navigated my doctoral studies. To my siblings, Kristina, Matthew, Lilleann, and Daniel, I’m so thankful for your lighthearted humor and the unique ways that you show your love and support. You help me remember the most important things in life. To my mom and dad especially, your belief in me never wavered. I am so thankful that you were there to keep me grounded in my faith and to encourage me to pursue the dreams God placed on my heart. To JB: God knew exactly who I needed alongside of me every step of the way and blessed me with you. I know that no matter what challenges we face, nothing is impossible when we hold on to our faith. I love you with all my heart. Here’s to new adventures! “Each of you should use whatever gift you have received to serve others, as faithful stewards of God’s grace in its various forms.” – 1 Peter 4:10 NIV iv A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches .................. 1 Self-Determination Theory ......................................................................................................3 Supplemental Education for Coaches .......................................................................................5 Method ....................................................................................................................................... 7 Research Approach ..................................................................................................................8 Procedures ...............................................................................................................................8 Sampling and Recruitment ...................................................................................................8 Intervention Pilot .................................................................................................................9 Intervention Details ............................................................................................................ 10 Quantitative Measures ........................................................................................................... 12 Qualitative Data Collection .................................................................................................... 13 Data Analysis ........................................................................................................................ 14 Results ..................................................................................................................................... 15 Participants ............................................................................................................................ 15 Program Effectiveness ....................................................................................................... 16 Perceptions of the Program ................................................................................................ 17 Discussion ................................................................................................................................ 23 Applied Considerations.......................................................................................................... 25 Limitations ............................................................................................................................ 27 References................................................................................................................................ 29 Figures ..................................................................................................................................... 36 Figure 1. Mixed-Method Research Design ......................................................................... 37 Figure 2. Intervention Timeline and Measurement Administration ..................................... 38 Figure 3. Change in Mean Values for Autonomy-supportive Coaching by Time and Condition ........................................................................................................................... 39 Figure 4. Change in Mean Values for Controlling Coaching by Time and Condition .......... 40 Tables....................................................................................................................................... 41 Table 1: Overview and Intervention Details: A Need-Supportive Intervention for Youth Hockey Coaches ................................................................................................................ 42 Table 2: Mean and Standard Deviation Values Across the Subscales of the SISQ-sport...... 43 Appendix A: Extended Literature Review ............................................................................. 44 The Youth Sport Coach in the U.S. ........................................................................................ 44 Coach Education.................................................................................................................... 45 v Models of Youth Athlete Development .................................................................................. 48 Long-term Athlete Development ........................................................................................ 48 Developmental Model of Sport Participation ...................................................................... 49 Positive Youth Athlete Development ................................................................................. 50 USA Hockey Coach Training Context ................................................................................... 52 Self-determination Theory ..................................................................................................... 53 Need-supportive Coaching Interventions in Youth Sport Contexts ......................................... 58 References................................................................................................................................ 68 Appendix B: Intervention Materials ...................................................................................... 76 Workshop 1 ........................................................................................................................... 76 Workshop 2 ........................................................................................................................... 78 Workshop 3 ........................................................................................................................... 80 Workshop 4 ........................................................................................................................... 82 Appendix C: Assessment Battery ........................................................................................... 84 Part 1. Demographics ............................................................................................................ 84 Part 2. Situations-in-Sport Questionnaire ............................................................................... 85 Part 3. Reflections 1, 2, & Stop-light ..................................................................................... 93 Part 4. Program Evaluation Questionnaire.............................................................................. 94 Appendix D: Handouts ........................................................................................................... 95 Workshop 1 – Handout .......................................................................................................... 96 Workshop 2 – Practice Plan ................................................................................................... 97 Workshop 2 – Developmental Considerations ........................................................................ 98 Workshop 3 – Myth Busting ................................................................................................ 102 Workshop 3 – Coaching Behavior Checklist ........................................................................ 103 Workshop 4 – Maintaining IMPACT ................................................................................... 105 Appendix E: Scenarios .......................................................................................................... 106 Scenarios used in Workshop 2 ............................................................................................. 107 Youth Coach Intervention 1 A Randomized Need-Supportive Intervention with U.S. Youth Hockey Coaches The average youth athlete in the U.S. quits their sport due to a lack of fun and enjoyment by age 11 after participating in sport for three years (Solomon, 2019). Meanwhile, determinants of youth athletes’ experience of fun include trying hard, positive team dynamics, and positive coaching (Visek et al., 2020). Fortunately, positive coaching and positive team dynamics are both external fun-factors that can be addressed through coach education and training (Visek et al., 2015). In fact, exceptional strides have been made in recent years to improve the youth sport experience through coach training initiatives. For example, the Million Coaches Challenge (n.d.) is a collective effort that aims to create and deliver evidence-based training in areas of youth development (e.g., motivation, relationship building) to a million coaches by 2025. The provision of accessible and affordable theory-driven coach education opportunities is important to address the current deficiencies in coach training in the U.S. (Fawver et al., 2020) and ensure quality sport experiences for youth on a broader level (Million Coaches Challenge, n.d.). A national survey of 10,485 U.S. youth sport coaches (Anderson-Butcher & Bates, 2022) revealed those in volunteer roles were less likely to have participated in training in areas of youth development (i.e., supporting mental health, building life skills), were more likely to never receive an evaluation of their coaching, and were less confident in their coaching practices when compared to paid coaches. Additionally, many youth coaches appeared to lack backgrounds in child development and education which are essential competencies when working with youth. Encouraging to note is coaches’ desire to receive such opportunities as 66–70% of respondents indicated an interest in being educated in areas such as motivational techniques, relationship building, and effective communication (Anderson-Butcher & Bates, 2022). Anderson-Butcher and Bates (2022) suggest that access to coach training opportunities should be strengthened for Youth Coach Intervention 2 volunteer and community-based coaches and, if possible, be delivered through a sport-specific national governing body to improve youth sport experiences and retention rates. USA Hockey has set itself apart as a National Governing Body that is committed to implementing a research-to-practice model. After recognizing deficiencies in their own coach and athlete development systems, leaders within USA Hockey set out to implement a comprehensive grassroots initiative grounded in long-term athlete development principles and child development best practices. Since its implementation in 2009, youth hockey coaches have been required to complete online modules that are age-specific for the level being coached upon registering as a USA Hockey coach (Martel, 2015). Additionally, coaches are expected to progress through three levels of certification (one per year) in areas of technical and tactical skills (Level 1), practice planning and coaching philosophy (Level 2), and coaching physiology and psychology (Level 3, valid for 2 years). Coaches of national tournament bound teams1 are expected to continue their training in areas of motivational, psychological, and teaching components of coaching (Level 4, valid for 3 years) and team play, player skill development, and physiological aspects of working with youth athletes (Level 5, valid for 4 years; Martel, 2015). With these adaptations in coach training alongside other programmatic shifts (e.g., age appropriate playing surface size), USA Hockey’s overall participation numbers continue to climb (i.e., 547,429 players in 2021-22 and 556,186 in 2022-23, USA Hockey, n.d.). Nevertheless, youth hockey coaches believe further improvement is needed in hockey coach education and expertise so that high quality coaching is delivered at all levels of youth 1Tier I 14U, 16U, and 18/19U and Tier II 16U and 18/19U Youth Coach Intervention 3 participation and not primarily in the upper levels of player development (Smolianov et al., 2020). Such experiences could be supported with continuing education opportunities that focus on topics not currently emphasized in Levels 1–5. While coaches’ professional knowledge is prioritized by USA Hockey, there is likely some opportunity to expand coaches’ interpersonal knowledge in areas of relationship building and motivation. The quality of the coach-athlete relationship is believed to be a fundamental component to athletes’ sport experience and success (Anderson-Butcher & Bates, 2022) and relies on the interpersonal knowledge of the coach. In some respects, the youth coach is viewed as a key social agent above the influence of parents and peers as athletes move toward higher levels of performance (McCann et al., 2022). Indeed, the behaviors and practices of the coach impact several essential athlete factors such as the quality of athlete motivation, well-being, and psychological functioning (McCann et al., 2022; Chu & Zhang, 2019). Unfortunately, youth coaches without appropriate training in athlete-centered principles may perpetuate harmful coaching practices that contribute to athlete burnout, drop-out, and even depression (Bartholomew et al., 2011). Self-Determination Theory A framework commonly used to understand the relationship between coaching behaviors and the psychological well-being and motivation of athletes is Self-Determination Theory (SDT; Ryan & Deci, 2017). According to the theory, all people possess three basic psychological needs: competence (i.e., sense of effectiveness), relatedness (i.e., sense of belonging), and autonomy (i.e., sense of volition). The quality of an athlete’s motivation is dependent upon the fulfillment and frustration of these three needs (Deci & Ryan, 2000). Athletes’ basic psychological needs can be fostered with need-supportive coaching which includes two different styles: autonomy supportive and structuring. Youth Coach Intervention 4 Coaches exercising an autonomy-supportive style (Delrue et al., 2019; Mageau & Vallerand, 2003) acknowledge athletes’ feelings, provide opportunities for choice, and display warmth and empathy in their communication to nurture athletes’ sense of psychological freedom. Specifically, an autonomy-supportive style includes a participative (e.g., prioritizing the input and interests of the athlete through opportunities for meaningful decision making and coach athlete dialogue) and an attuning approach (e.g., an acknowledgement and acceptance of athletes’ emotional responses and perspectives, providing explanations that are meaningful, attempting to make activities of interest to athletes). Meanwhile, a structuring style supports athletes’ sense of mastery and growth through a process-focused approach to instruction and feedback (Delrue et al., 2019). This style is made up of a clarifying (e.g., communication of clearly set goals and expectations, monitoring athlete growth) and guiding approach (e.g., offering help and constructive feedback to support athletes’ progress). Coaches can also frustrate the psychological needs of athletes through the intentional or unintentional use of need-thwarting coaching, which is also comprised of two distinct styles: controlling and chaotic (Bartholomew et al., 2011; Delrue et al., 2019). Behaviors such as communicating with athletes in an authoritarian manner and utilizing pressure and manipulation to obtain a desired response are characteristic of controlling coaching. The pressure experienced from the coach becomes the basis for athlete behavior which, in turn, undermines athlete’s sense of autonomy and self-determination (Bartholomew et al., 2009). The controlling style is segmented into a demanding (e.g., use of rewards, commanding language, threats, and a focus on athlete obligations) and domineering approach (e.g., manipulative tactics to drive athlete behavior that invoke feelings of shame and anxiety). On the other hand, chaotic coaching is often a confusing experience for athletes as the coach will lack consistency in their interpersonal tone Youth Coach Intervention 5 and instructional goals. Expectations may remain unclear with this type of style and may negatively impact athletes’ goal achievement and skill acquisition. A chaotic style is divided into an abandoning (e.g., giving up on athletes after intervening) and awaiting approach (e.g., waits for athletes to take initiative and does not plan much; Delrue et al., 2019). Supplemental Education for Coaches Mossman et., al. (2022) conducted a meta-analysis of 131 independent samples (N = 38,844) and analyzed correlation effect sizes for coach need support in exercise and sport settings. The authors confirmed strong positive correlations for need support and basic psychological need satisfaction, autonomous athlete motivation, and general well-being while moderate negative correlations were reported for need support and basic psychological need frustration and burnout. To improve athlete outcomes of well-being and autonomous motivation, authors recommended the development of coach training programs to improve coaches’ use of need-supportive behaviors. Typically, coaches will use a combination of need-supportive and need-thwarting behaviors (Benish et al., 2023; Carroll & Allen, 2021) but can be taught how to enhance their need-supportive behaviors and limit need-thwarting tendencies (Readdy & Raabe, 2016). In a systematic review of 21 interventions in youth and physical education (PE) contexts (published in years 2006 – 2018), need-supportive training programs were deemed effective in positively impacting PE teacher’s and youth coaches’ need-supportive behavior, students’ and athletes’ basic psychological need satisfaction, students’ and athletes’ motivation, and burnout (Raabe et al., 2019). To date, seven need-supportive interventions have been specifically implemented in youth sport contexts with varying degrees of effectiveness (Cece et al., 2021; Langdon et al., 2015; Langan et al., 2015; Mahoney et al., 2016; Pulido et al., 2017; Reynders et al., 2019; Youth Coach Intervention 6 Wachsmuth et al., 2022). For example, Reynders and colleagues (2019) reported improvements in Belgium coaches’ need-supportive behavior, and enhanced perceptions of athlete engagement and autonomous motivation after four workshops across a period of nine weeks. In a high performance context, Cece and colleagues (2021) found their coach intervention program meaningfully increased youth elite table tennis athletes’ experience of positive emotions (i.e., happiness, excitement) and reduced negative emotional responses (i.e., anger, anxiety). Additionally, the program helped athletes maintain their self-determined motivation with authors suggesting the program helped buffer the pressures of their intense training environment. Athletes have also reported reductions in their perceptions of need thwarting and improvements in perceptions of need satisfaction after their soccer coaches completed a 12-hour need-support training (Pulido et al., 2017). While several need-supportive coaching interventions have demonstrated some favorable coach and athlete outcomes (Cece et al., 2021; Cheon et al., 2015; Pulido et al., 2017; Reynders et al., 2019), in youth contexts, several interventions have been limited in their effectiveness (Langan et al., 2015; Langdon et al., 2015; Mahoney et al., 2016). Collective barriers recognized included coaches’ skepticism, relapses in coaching behavior, training length, dissonance between the content of the training and the coaching environment, and limited opportunities to reflect on their implementation of skills (Langan et al., 2015; Mahoney et al., 2016; Wachsmuth et al., 2022). Specifically, in Wachsmuth and colleague’s (2022) work, the degree to which interventions directly addressed how to incorporate need support in youth contexts was unclear but was noted as a critical area for improvement. Furthermore, need-supportive trainings conducted in the U.S. are especially lacking (e.g., Langdon et al., 2015). Recently, researchers advocated that youth sport coaches may need additional guidance Youth Coach Intervention 7 on how to best implement strategies that foster need-support and reduce need-thwarting for athletes of varying ages and developmental experiences (Benish et al., 2023). For example, coaches working with athletes in middle childhood (ages 6–10; Vernon & Chen, 2024) can meaningfully support self-esteem development and competence by focusing on athletes’ improvements in skill in their feedback while limiting critiques of athlete performance (Côté et al., 2010). Similar guidelines could potentially address the incongruence many youth athletes experience in what they want and need out of their sport experience (e.g., sense of belonging, enjoyment) and what sport clubs offer (e.g., emphasis on winning, limited playing time for those less skilled; Persson et al., 2020). Therefore, the purpose of the present study is to explore the efficacy of a need-supportive intervention on youth hockey coaches’ attitudes toward, and reported use of, need-supportive and/or need-thwarting approaches. The primary research question is “what is the efficacy of a need-supportive coach training on youth hockey coaches’ reported use of autonomy-supportive and controlling styles?” A secondary research question is “what are youth hockey coaches’ perceptions of a need-supportive coach training program?” It is hypothesized that participants in the intervention group, relative to members of the delayed control group, will report becoming more autonomy-supportive from pretest to posttest (H1) and will report a reduction in controlling practices from pretest to posttest (H2). Method The current study used a quasi-experimental mixed methods design with a delayed control. Both sequential and concurrent data collection methods guided the gathering of quantitative and qualitative data over the course of a 7-week intervention to assess the program’s efficacy in improving coach need-supportive behavior and reducing controlling coaching approaches (see Figure 1). These data collection methods enhance the literature as few need Youth Coach Intervention 8 supportive interventions with youth coach populations have explored program outcomes from a mixed-methods perspective (e.g., Langdon et al., 2015). Research Approach A post-positivist research paradigm guided the current study. This approach views objectivity as relative and data as imperfect and inherently biased. Examining the effectiveness of a need-supportive intervention from more than one angle (quantitative and qualitative) thereby aims to reduce the uncertainty of the results and accommodate for the limitations of certain data collection methods (Panhwar et al., 2017). Lastly, the first author/workshop facilitator used reflexive journaling (Watt, 2007) after each workshop to ensure consistent delivery of program content and to bring forward any observations or initial interpretations of participants’ program perceptions. This method served to minimize bias in the final interpretation of study findings. Procedures Sampling and Recruitment Upon IRB approval, participants were recruited through purposive and convenience sampling methods. All 8U–14U head coaches (N = 217) representing 27 member associations in a USA Hockey recognized regional league were emailed and invited to participate in the study. Additionally, recruitment flyers were disseminated through the primary author’s professional and social media accounts (e.g., LinkedIn) and personal network. Coaches self-selected to enroll in the need-supportive training and were required to submit the following demographic information: age, level of hockey coaching (e.g., 10U), name of the team currently coaching, and current coaching role (i.e., head coach, assistant/volunteer). Twenty-nine individuals expressed interest in the training, however, three did not meet the study criteria and were excluded from data collection. Participants (N = 26) were randomly assigned to the intervention condition (n = Youth Coach Intervention 9 11) or delayed control condition (n = 15) at the end of the enrollment period. When both a head coach and assistant coach from the same team agreed to participate in the study, both were included in a condition together (i.e., intervention group, delayed control group) to ensure the fidelity of the intervention and control groups. A group of four coaches (one head coach and three assistant coaches) from the same team were randomly assigned to the intervention group. Upon group assignment, the lead author contacted participants via phone and asked them to confirm their participation. The recruitment email informed the coaches of the study’s purpose and the potential benefits of participating in the training program. Participants were delimited to include coaches who were currently (1) members of USA hockey, (2) registered as a head or assistant/volunteer coach for the 2023–2024 season, and (3) working with hockey players between the ages of 6–14 years. One member of the intervention group dropped out before the start of the training, one member of the control group stopped attending after the second workshop, and three members of the control group opted to complete the delayed training asynchronously and therefore did not complete a post-intervention assessment. Participant consent was obtained from all coaches before data collection. Intervention Pilot The intervention protocol was piloted with a sample of hockey coaches with youth coaching experience (N = 9). Coaches engaged with all workshop material and were asked to provide feedback on session information and activities. Information from this pilot intervention informed adaptations in module structure, session activities, options for engagement, post session handouts, and use of reflection tools to allow for an enhanced participant experience. No data was collected from the pilot group; however, reflexive journaling was utilized by the first author/workshop facilitator after each workshop to record any coach feedback, personal Youth Coach Intervention 10 observations, and note the rationale for any changes to the final intervention protocol. The pilot revealed a need to bolster the integration of hockey-specific scenarios applicable to the youth coaching context to help coaches better understand how to implement the strategies offered in Workshops 1 and 2. From this feedback, three scenarios were created (Appendix E) and integrated into the second workshop and were informed by the motivation related challenges described by coaches during the pilot sessions. Scenarios highlighted the developmental level of the player(s) (i.e., 10U, 12U, and 14U) and guided coaches to consider the athlete(s) degree of need fulfillment when deciding what motivational strategies might resonate with player(s) in the given situation. Finally, the pilot also revealed areas for improvement such as the inclusion of a reflection tool at the conclusion of each workshop (e.g., Stop-light reflection: “From today’s workshop, name 1-2 things you plan to stop doing [Red], 1 2 things you plan to continue doing [Yellow], 1-2 things you plan to start or go do” [Green]) which provided coaches with the opportunity to consider future changes in behavior as a result of their learning. Workshops 2, 3, and 4 were also adjusted to have all coaches sharing their reflections of how they were implementing various motivational strategies as one group instead of in breakout rooms to save time and allow coaches to hear other’s creative approaches to applying program content. Lastly, the workshop supplemental materials (Appendix D) were expanded from two pages to ten after the pilot. This approach allowed more time in sessions for coaches to share experiences with one another while still receiving the necessary content. Intervention Details The intervention (see Appendix B for outline) was led by the first author who has ten years of experience coaching group and individual figure skating and basic hockey skills, five years of experience in applied mental performance consulting with athlete populations, one year Youth Coach Intervention 11 of experience counseling, five years of research experience in need-supportive coaching and one previous virtual workshop which was facilitated for coach developers of USA Soccer using a Self-Determination Theory lens. Her theoretical orientation combines cognitive behavioral therapy, acceptance and commitment therapy, and Self-Determination Theory. As such, she sought to promote a need-supportive environment for all coaches by demonstrating empathy, providing positive feedback and choices, and being open to coaches’ perspectives. The intervention was entitled ‘Driven on Ice: A Motivation Masterclass’ and was informed by current research on the use of need-supportive and need-thwarting coaching in sport (Bartholomew et al., 2011; Benish et al., 2023; Delrue et al., 2019; Mageau & Vallerand, 2003). Adapted from Reynders and colleagues’ (2019) design, the seven-week intervention (see Figure 2 for timeline) consisted of four, one-hour workshops that were delivered virtually with one week in between each workshop. Coaches could choose to attend one of three group workshop time offerings each week (i.e., afternoon and evening options available; 22 total group sessions delivered). Group session size ranged from 2–8 participants (M = 3.5). Multiple time offerings allowed coaches to attend the session that was most convenient and reduced drop-out. In the event a coach could not attend a group workshop, a make-up session was offered in which the coach viewed a recorded group session on Zoom with the lead facilitator and responded to workshop prompts and activities in a one-on-one format. Four coaches utilized one make-up session and two coaches utilized two make-up sessions. If a coach could not accommodate a make-up session, the coach was instructed to watch a recording of the session and submit any required survey measures or reflection responses. Four coaches engaged in one session asynchronously. Coaches had to attend at least two of the four workshops during a scheduled group offering for their data to be included in analysis. All but one coach met this threshold and Youth Coach Intervention 12 stopped attending after workshop 2. All group and make-up sessions were video recorded. An overview of workshop elements and activities can be found in Table 1. The acronym, IMPACT, was created for the intervention using existing guidelines for need-supportive coaching (Delrue et al., 2019; Mageau & Vallerand, 2003) to help coaches practically implement the approach: Independent work and initiative taking, Magnify individual improvement, Positive and informative feedback, Accept and incorporate athlete input, Choice with limits, and Tune in and validate athlete’s emotions and interests. Each strategy was supported with sport-specific examples and age-related adaptations as relevant. Throughout the workshops, coaches could reflect on the barriers to implementing coaching strategies, participate in group and individual reflections, respond to scenarios and discussion prompts, and verbally share their application experiences with one another. Participants of the control group fully participated in the training starting at week 7 after completing their second baseline of the SISQ-sport (see below). Quantitative Measures Descriptive Variables. At the start of the intervention, participants’ age, self-identified gender, self-identified race and ethnicity, years coaching, age group(s) coached (e.g., 10U), current coaching title (e.g., head coach), and current level of USA Hockey certification were collected. At post-intervention, coaches reported the total number of practice sessions they attended while engaging in the intervention. Situations-in-Sport Questionnaire. The Situations-in-Sport Questionnaire (SISQ-sport; Delrue et al., 2019) is constructed to measure coaches’ perceived use of need-supportive and need-thwarting coaching styles through responses to a series of sport-scenarios involving coach athlete communication. The SISQ-sport has been previously implemented as a form of assessment after coaches participated in an intervention that was designed to change participants’ Youth Coach Intervention 13 (de)motivating style (Reynders et al., 2019). The SISQ-sport was administered at two time points for the intervention group (Week 1 and Week 7) and three time points for the delayed control group (Week 1, Week 7, and Week 13) to assess coaches’ self-rated need-supportive (i.e., autonomy-supportive, structuring) and need-thwarting (i.e., controlling, chaotic) behaviors (see Figure 2). After reviewing each of fifteen sport scenarios, coaches indicate on a 7-point Likert scale how well each of the four possible responses would describe them (i.e., 1 = does not describe me at all to 7 = described me extremely well). Of the four responses to each vignette, each corresponds to a type of motivational approach: autonomy-supportive (i.e., participative or attuning), structuring (i.e., clarifying or guiding), controlling (i.e., demanding or domineering), or chaotic (i.e., abandoning or awaiting). Vignettes reflect either the pedagogical role of coaches, situations within training, or situations within competition that all require coach intervention. Internal consistency evidence within the current sample at the varying time points ranged from α = 0.84 to 0.85 for autonomy support, α = 0.54 to 0.75 for structure, α = 0.70 to 0.79 for control, and 0.73 to 0.76 for chaos. Two items were dropped from the structuring subscale (Situation 3.2 and 15.4) to reach an acceptable alpha of at least 0.7 for two of the three time points. Qualitative Data Collection In between each workshop, coaches had two weeks to apply strategies learned in the previous workshop into their daily practice and record written reflections of their use of interpersonal behaviors (2 total reflections). Participants reflected using specific prompts (e.g., “What motivational technique(s) did you try to implement this week?”) and electronically submitted those reflections at the start of the second and third workshop. Participants’ reflective responses to the “stop-light” tool were also gathered at the end of the third workshop to capture the behaviors coaches intended to reduce. Youth Coach Intervention 14 A program evaluation questionnaire was administered to both groups at the conclusion of the fourth and final workshop. This final assessment utilized open-ended questions to capture participants’ perceptions of the program’s importance (e.g., “How important do you consider the topic of the intervention and why?”), the developmental components and application (e.g., “How was your understanding of athlete development and motivation impacted by the training?”), the learning experience (e.g., “What aspects of the training supported your overall learning and implementation of knowledge? How does this compare to other coach trainings you have participated in?”), and recommendations for improvement (e.g., “What, if anything, would you have liked to be different about the training?”). Data Analysis The data was checked for missing values and three open items were present in the second administration of the SISQ-sport accounting for 0.2% of values reported by participants. An average subscale score was calculated and manually imputed for each missing item. Descriptive statistics were calculated for the demographic information. Chi-square tests were used to check for significant differences between the intervention and control conditions regarding participant demographics. Then, Cronbach’s alpha was calculated to assess the reliability of the SISQ-sport subscales (i.e., autonomy-supportive, controlling, structuring, chaotic). A 2x2 mixed measures ANOVA was used to determine differences in coaches’ perceived need-supportive and need thwarting coaching responses (SISQ-sport scores) from pre-test to post-test in the intervention and control conditions (i.e., time*condition). The alpha level for this statistical analysis was set to p < .05. Tests for normality and homogeneity were checked. Three members of the research team conducted the qualitative analysis before the quantitative results were calculated to prevent any unnecessary influence of one source’s results Youth Coach Intervention 15 on the other. To explore participants perceptions, participant’s written reflections and program evaluation questions were deductively analyzed by question or content focus (e.g., implementation efforts) with inductive coding across responses (i.e., hybrid approach; Fereday & Muir-Cochrane, 2006). Provisional codes (see Saldana, 2016) were created to correspond with the content of each question and additional in vivo codes were added by each member of the analysis team during the independent portion of the coding process. Researchers then met to discuss and reconcile codes and refine code names. All codes were compared across the sources of data and themes were developed. A member of the research team acted as a critical friend (Smith & McGannon, 2017) to encourage reflexivity and aid in theme development, refinement, and the final labeling of lower- and higher-order theme names. As an example, when discussing coaches’ implementation efforts, the first author drew attention to the frequency and types of strategies coaches reported using in comparison with how strategies were taught during workshops. While reflecting with the critical friend, it was noted that coaches’ implementation was, in fact, more deeply driven by contextual factors such as athlete development, the environment, and a coaches’ preferred style. Such discussions contributed to the rigor of the qualitative analysis through the challenging and developing of interpretations and helped to minimize the bias of the first author/workshop facilitator, consistent with established guidelines (see Smith & McGannon, 2017). For reporting purposes, participants were assigned a pseudonym to protect their identity. As the manuscript was composed, the quantitative and qualitative results were compared, and complimentary findings were integrated in the discussion. Results Participants A total of 25 youth hockey coaches (21 male, 4 female) participated in the study. All Youth Coach Intervention 16 coaches self-identified as White/Caucasian and represented 15 different youth hockey associations and 35 youth teams across five US states. Coaches were on average 43.4 years old (SD = 9.01, range = 24–64) and had coached for 8.26 years on average (SD = 6.16, range = 0.5 25). Twenty-one coaches indicated they held the title of head coach (18 male, 3 female) while the remaining four coaches were exclusively in an assistant coaching role (3 male, 1 female). Thirteen coaches (52%) were actively coaching 2–3 age groups while the remaining twelve coaches (48%) worked with one age group. Coaches worked with 8U (n = 4), 10U (n = 12), 12U (n = 7), 14U (n = 11), and high school aged (n = 5) athletes. Participants held the following USA Hockey certifications: Level 1 (n = 3), Level 2 (n = 3), Level 3 (n = 2), Level 4 (n = 14), Level 5 (n = 3). Participants reported directing an average of 13.1 total practices (SD = 5.96, range = 6 30) during the seven-week intervention. No significant differences between the intervention and control group were observed on age, years of coaching, coaching role, or gender. Program Effectiveness To address the first research question, a 2x2 mixed measures ANOVA was run to determine differences in coaches’ perceived need-supportive and need-thwarting coaching responses (SISQ-sport scores) from pre-test to post-test in the intervention (n = 21) and the waitlist control (n = 15) conditions. The alpha level for this statistical analysis was set to p < .05 and assumptions for normality and homogeneity were met. Three of the four Condition X Time interaction effects were significant (see Figures 3 & 4). The intervention group showed a significant interaction for coaches’ self-reported autonomy-supportive coaching (medium effect; ηp2 = .11, p < .05), controlling coaching (large effect; ηp2 = .20, p = .007), and chaotic coaching (large effect; ηp2 = .22, p = .004). There was not a significant interaction for coaches’ structuring behaviors (ηp2 = .002, p = .79). Interpretation of these results indicated that the program had a Youth Coach Intervention 17 moderate to large effect on most self-reported coach behaviors. Specifically, the hypotheses for the current study were supported in that the intervention group, relative to the members of the control group, improved their autonomy-supportive coaching from pre-test to post-test (H1) and reduced their controlling practices from pre-test to post-test (H2). See Table 2 for the full mean and standard deviation values at pre- and post-test by condition and subscale. A closer look at the mean values shows participants’ autonomy-supportive coaching increased (Δ = 0.54) for the intervention group while the control group showed negligible improvement (Δ = 0.10). Meanwhile, the intervention group decreased their controlling coaching (Δ = –0.44) while the control group increased in controlling coaching (Δ = 0.23). Likewise, the intervention group decreased their chaotic coaching (Δ = –0.15) while the control group increased these behaviors (Δ = 0.28). Perceptions of the Program The qualitative content analysis resulted in four primary themes that captured participants' viewpoints of and engagement in the need-supportive intervention: positive view of training, program enhancers, program barriers, and training experiences. Supporting quotes are presented below and interpreted alongside SISQ-sport results as appropriate to address research question two. Coach’s pseudonym and the age group(s) they coached are noted with each quote. Positive View of Training. The following subthemes contributed to participants’ positive view of the training: positive experience, topic importance, and comparison with other trainings. Youth coaches offered comments related to their enjoyment of the training both at the mid-point and final assessment, as evidenced by the following, “This has been a great course and learning opportunity,” (Simon 12U). Others noted how the program affirmed practices they currently implemented, “I think [the training] reaffirmed a lot of what I already believed and try to Youth Coach Intervention 18 practice,” (Christine 14U). This finding aligns with coaches’ above average (M = 5.15, SD = .89) reported use of autonomy-supportive coaching practices at baseline. Further, coaches considered program content significant to their work with young children, “With kids, the psychological aspect to their development is arguably more important than the tangible skills,” (Kevin 10U) and “paramount to a coach's success” (Charley 8U/10U). Combined, these findings indicate coaches who chose to participate may have already been interested in supporting youth athletes’ needs given pre-existing beliefs of what coaching approaches support athlete development. In the program evaluation reflection, many participants expressed their belief that knowledge of athlete motivation was key to effective coaching and positively impacting youth athlete engagement. In fact, several coaches commented that other coaches “need this type of training,” (Bruce 14U) and how “it should be a part of USA Hockey's coaching development program” (Devon 8U/12U). Finally, a few coaches commented on their other training experiences when reflecting on their time in the current intervention and noted that their USA Hockey trainings served as a good foundation for the age-related content in the workshops. That said, coaches felt the depth of Driven on Ice enhanced their knowledge of the “soft skills” of coaching and “far exceeds the content [USA Hockey] has for motivating players” (Devon 8U/12U). Interpretation of these findings indicates that participants found the training to be valuable, detailed, and supportive to their work with youth athletes. Program Enhancers. Several program elements were highlighted by participants as facilitative to their learning, represented within the program modalities including practical strategies, small group interaction, and reflection opportunities. Practical strategies offered throughout the training were illustrated with sport-specific examples and presented as memorable acronyms (e.g., IMPACT, CAR), metaphors (e.g., fueling athlete motivation), and Youth Coach Intervention 19 short phrases (e.g., 5:1 feedback ratio) to support coach learning. Patrick (14U) appreciated how “there was actionable things taken away from the training and ideas that could be implemented immediately.” Kevin (10U) noted how the structure of the strategies was useful in funneling his approach, “IMPACT helps me direct and give purpose to the positivity to better nourish [athlete] growth.” Coaches would often refer to acronyms in their reflections, “some kids required a little more positive and informative feedback than others,” (Dustin 12U/16U) further illustrating the accessibility of how strategies were delivered. Small group interaction and discussion appeared to be another program enhancer as it allowed coaches to effectively share experiences, act as a source of validation, and allow coaches to offer each other guidance or receive help. Bruce (14U) noted how interacting with other coaches supported his learning experience, “It’s always better to hear and listen to peers as well as an instructor. More involvement from the students makes for deeper learning.” Adrian (10U) similarly shared, “I appreciated the group aspect along with the conversational tone, as compared to watching stale videos and slide decks with fewer group discussions.” Finally, coaches expressed that the reflection opportunities (e.g., homework, written, verbal) across multiple sessions enhanced their experience. Isaiah (12U/14U) valued the multiple opportunities to debrief his application of learned material, “Most other training you were remembering back [information] and couldn’t implement and report back. I loved this aspect of the training.” Meanwhile, Devon (8U/12U) felt that “the concepts, approaches, and reflections within this course have helped me to change my mindset on how to be a more effective coach.” Lastly, Darrell (10U) found that other coaches reporting back to the group helped his own sense of competence, “I like having the topics and then hearing the input of other coaches. It really helps with confidence in what we are doing and that you can make a difference with players.” Youth Coach Intervention 20 From these perspectives, the practical nature of the content, the learning environment, and the activities provided were beneficial to coaches’ learning. Program Barriers. As expected, participants identified a few key elements that served as barriers or limiting factors to their use of program content: other coaches, environmental factors, and personal factors. Several coaches when implementing IMPACT coaching commented on their role as an assistant or head coach and how this occasionally limited their ability to exercise learned material. For instance, Isaiah (12U/14U) stated he could not use choice with limits as an assistant coach for his 14U team because, “the head coach (barrier) wanted to be structured in his practices before games.” Many assistants recognized that they did not control the overall coaching environment and needed additional support getting group consensus, “Arming us with the data to convince other coaches that these approaches are more successful than traditional approaches [would] enable better buy-in and proliferation of the concepts” (Charley 8U/10U). Head coaches also experienced challenges with assistant coaches when implementing strategies: “We don’t have a lot of time to discuss or work through to consensus…that's caused some friction or frustration…[the assistant coach] kind of tuned out during practice and I had to make a decision of dealing with the kids’ emotional needs or his" (Martin 12U/14U). Generally, “blending coaching styles can be a challenge on teams when there are larger coaching staffs” (Stephen 12U/14U/16U) and, as noted by participants, may extinguish efforts to employ new and evidence-based strategies. Conversely, a group of four coaches from one team all participated in the program which appeared to allow for a more comprehensive use of tools, “I implemented all [IMPACT strategies] or other coaches did” (Gary 10U). Further, environmental factors such as limited time in practice was occasionally perceived as a barrier, as illustrated by Charley (8U/10U) who reflected that when there is “only Youth Coach Intervention 21 so much time, [it’s] hard to maintain 5:1 when you are in a game and working to correct mistakes.” Coaches also noticed that situations dictated what need-supportive strategies could be implemented, “[I used] M & P given we were in the end of year contests and there were fewer or no practice slots…other [strategies] tend to apply a little better for younger athletes” (Adrian 10U). Consequently, coaches may not have tried specific strategies if the tool did not match the needs or constraints of their coaching environment. Personal factors such as alignment with personal coaching style and self-efficacy appeared to occasionally restrict coaches’ use of program material. A few coaches noted how some strategies were uncomfortable to try or were a stretch from their normal coaching behaviors, “IMPACT does conflict [with my style] in that it requires me to allow the athlete a larger say in how and what they do…I am still skeptical on how well some of these concepts will work long term.” (Patrick 14U). Jacob (8U/10U) noted a similar experience, “It felt a little disorganized for me personally as someone who overdoes practice planning, but [I] embraced it and enjoyed more of the back and forth than usual. [I] felt more connected.” Meanwhile, Dustin (12U/16U) recognized that some motivational strategies involved effort and “required some strategic planning” to offer choices in-line with the skills athletes needed to develop. A few coaches like Jacob (8U/10U) seemed overwhelmed with the task of consciously supporting athlete needs, explaining, “…there's so much on our plate as coaches already that it feels like more to do to think about how I practically implement all of these concepts…the iterations and techniques feel like a lot at the moment.” Training Experiences. During their participation, coaches expressed their training related experiences in three main areas: new learning, implementation efforts, and perceived athlete outcomes. Several participants identified that the training supported their previous Youth Coach Intervention 22 knowledge with greater depth, “[I] learned a few things to keep doing (and why) and learned a few new ones” (Kevin 10U). Coaches reported that they learned the importance of reducing demotivating practices like yelling. For instance, Dustin (12U/16U) commented, “It’s easy to yell and scream at them, to try and motivate them, but that has limited usage and success." Other demotivating practice coaches reflected on included exercise as punishment, critical feedback, and comparison (e.g., “[I want to] stop comparing individuals, especially when the comparison isn’t asked for” (Adrian 10U)). Overall, coaches increased their awareness of the impact of their behaviors and the environment they create on athlete motivation, reflecting, "every little thing matters. The words that are said, the tone they are said with, body language while speaking, the setting when talking all come into play on the impact a coach can have on an athlete" (Bill 10U). During the intervention, coaches tried specific behaviors with their teams from the IMPACT framework to support athlete motivation with some reporting low implementation, like Jacob (8U/10U) who explained, “Maybe my lack of creativity but didn’t feel that I had a chance to really implement in the last week with our schedule…[I] was maybe a little more positive than usual but that was it.” Other coaches like Gary (10U) reported moderate implementation as he reflected, “We switched lines and asked players what position they wanted to play (choice with limits). I gave thoughtful, positive feedback after shifts during the games.” Finally, a few coaches engaged in high implementation, stating, “I tried to implement all of them” (Martin 12U/14U). As they reflected on their efforts, many coaches found value in the variety of approaches they learned. According to Bill (10U), “Having all of the different IMPACT behaviors allows [me] to utilize what works best with different athletes.” Similarly, coaches could identify how certain strategies applied to athletes of certain ages. As observed by Stephen (12U/14U/16U), “At the U12 level, athletes are very sensitive to positive feedback. They are still developing emotionally Youth Coach Intervention 23 and are very perceptive regarding tone.” These implementation efforts as described were reflected in significant improvements in autonomy-supportive coaching and significant reductions in controlling coaching behaviors in the SISQ-sport from pre- to post-test. Finally, coaches were instructed to attend to how the use of program content impacted their players. Several reported observing positive outcomes including positive emotional responses (e.g., excitement, happiness), improvements in confidence, a deeper connection with players, resilience through challenge, and increased engagement. Darrell (10U) noticed enhanced effort after having athletes choose the last practice activity, stating, “they wanted to do a scrimmage and we went an extra 40 minutes. They wanted to keep going, but the Zamboni driver had to go home.” Meanwhile, Gary (10U) started to “notice the negative responses from players when not implementing [IMPACT] techniques.” On occasion, coaches perceived more mixed results as noted by Jim (10U) who implemented positive and informative feedback, and noticed, “You can see some kid’s eyes glaze over, and you lose their attention. Others are receptive. It has to do with individual attitudes.” Nevertheless, many participants could identify advances in their own knowledge and observed positive athlete outcomes while exercising program material. Discussion This intervention merged components of Reynders and colleagues’ (2019) successful, four-session training design with several innovative approaches (i.e., virtual delivery, small group discussion, practical strategies, age-related guidelines, flexible-time slots) and the addition of psychoeducation regarding controlling coaching to meet the learning needs of youth sport coaches while they were in-season. Consistent with Reynders et al.’s (2019) intervention, youth hockey coaches significantly improved their autonomy-supportive coaching behaviors and significantly reduced their use of controlling approaches when compared with a delayed-control Youth Coach Intervention 24 group. Likewise, no significant changes were observed for coaches’ structuring behavior in either condition, with coaches reporting high levels of this approach at pre-test (M = 5.84, SD = .46), which may indicate pre-existing training from USA Hockey or another source that could have imposed ceiling effects. In contrast with Reynders et al. (2019), coaches who completed the intervention significantly reduced their chaotic coaching behaviors. This effect may be attributed to the present program’s direct approach of instructing coaches to reduce need-thwarting approaches and use consistent communication. Also of note, the control condition revealed that without the training, coaches increased in both controlling and chaotic coaching approaches over a seven-week period. This effect may be explained by the time of the season as many coaches were preparing for playoffs and may have experienced increased pressure and/or stress during this period. In the qualitative data, youth coaches appeared to have a positive experience with the program and found the topic of motivation to be critical to their work with children. Other SDT based programs, however, have received mixed responses. Wachsmuth and colleagues (2022) found that coach coordinators who were responsible for facilitating need-supportive educational program across a talent development program viewed the program favorably and important to the context with which it was delivered. Unfortunately, the youth coaches who were receiving the material demonstrated low engagement, skepticism, and viewed the need-supportive style as time-consuming. It appears important for coach training initiatives to establish buy-in, relate to coaches’ immediate context and needs, and ensure learned concepts are transferred into the sport setting (Gilbert et al., 2009; Smith et al., 2017). In the present study, coaches could articulate how the program content benefitted them and their role, which appeared to be driven by coaches’ iterative implementation efforts and subsequent observations of personal and athlete outcomes, Youth Coach Intervention 25 many of which were positive (e.g., improvements in athlete engagement). Program content also seemed to fit well with coaches’ previous knowledge of youth athlete development which was likely due to USA Hockey’s rigorous training structures for its youth coaches with progressive certification levels, age-specific modules, and continued learning opportunities (Fawver e

Sport Injury-Related GrowthDOCTORAL THESIS Sport Injury-Related Growth Theory-to-Practice Roy-Davis, Kylie Award date: 2017 Awarding institution: University of Roehampton General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 20. avr.. 2025 Sport Injury-Related Growth: Theory-to-Practice Kylie Roy-Davis A thesis submitted in partial fulfillment for the degree of PhD Department of Life Sciences University of Roehampton 2017 i This thesis is dedicated to Adam. ii Declaration This thesis is the author’s own work, and has not been previously submitted for an award of this university or any other institution. Signed:…………………………….. Date:……………………………….. STATEMENT 1 The content of the thesis is legally allowable under copyright legislation. Signed:…………………………….. Date:……………………………….. STATEMENT 2 I hereby give consent for my thesis, if accepted, to be available for photocopying and for interlibrary loan, and for the title and summary to be made available to outside organizations. Signed:…………………………….. Date:……………………………….. iii Summary This thesis explored the concept of sport injury-related growth (SIRG). Specifically, the mechanisms through which growth occurs and how it may be promoted for injured athletes. Study 1 used a grounded theory methodology to develop a context-specific theory. Aligning with a Straussian approach, data was collected using semi-structured interviews and analysed using open, axial, and selected coding. Findings revealed that the mechanisms of (a) meta-cognition, (b) positive reappraisal, (c) positive emotions, and (d) facilitative responses are what enable SIRG. These mechanisms are influenced by a combination of internal (e.g., personality) and external (e.g., received social support) factors. These factors enable injured athletes to alter their perception of their injury into an opportunity for growth, and it is by drawing upon and mobilizing a variety of these resources that athletes are able to experience SIRG. Dimensions of growth were psychosocial, physiological, and behavioral. Although this study produced a theory that explains the SIRG process, it does not propose specific techniques or therapies that encourage the development of growth. To address this issue, Study 2 aimed to investigate and identify evidence-based interventions that promote growth after experiencing adversity. To achieve this aim, a systematic review was conducted on literature pertaining to the promotion of growth for populations who have undergone a stressful experience (e.g., medical illness). In total, 34 studies were located and obtained that met the preplanned inclusion criteria. Within these 37 studies, three types of interventions were identified: emotional processing, cognitive processing, and combined techniques. The authors of the studies who successfully demonstrated the promotion of growth either identified or suggested that growth occurs through the mechanisms of cognitive restructuring and/or reappraisal. Other important considerations that were identified through this review were the duration and timing of the intervention in relation to the adverse event, and the importance of the intervention meeting the needs of the participants. Although this study offers valuable insight into how growth may be more successfully nurtured, the studies included within this review did not specifically focus on promoting growth for injured athletes. Consequently, Study 3 sought to complement this study by examining the practice-based experiential knowledge of sport psychologists who have worked with injured athletes in an applied manner. In total, 10 sport psychologists were purposively sampled and interviewed. Data was collected using a semi-structured interview guide and analysed using content analysis. Findings revealed a fluid development framework that consisted of 5 phases: (a) reactionary phase, (b) preparation phase, (c) reflection phase, (d) application phase, and (e) monitoring phase. Within each phase a set of corresponding strategies, skills, and tools were identified that the sport psychologists would utilize to match the needs of the athletes. The sport psychologists also identified a number of personal and environmental factors that either promoted or hindered the development of SIRG. Altogether, this thesis supports and extends research regarding growth and sport injury, as well as offering applied practitioners useful information for promoting SIRG. iv Table of Contents Page Dedication……………………………………………………………………………….... i Declaration……………………………………………………………………………….. ii Summary………………………………………………………………………………….iii Table of Contents…………………………………………………………………………iv Publications and Presentations……………...……………………….……….…...... ……ix Appendices………………………………………………………………………....……...x Tables……………………………………………………………………………………..xi Figures…………………………………………………………………………………... xii Acknowledgements……………………………………………………………………...xiii Chapter 1: Introduction…………………………………………………………………1 What is this Ph.D. about?.............................................................................................2 Background…………………………………………………………………………..2 Conducting research………………………………………………………………….4 Overview……………………………………………………………………….....….6 Chapter 2: Literature Review.........................................................................................11 Abstract ......................................................................................................................12 Introduction ................................................................................................................13 Responses to Sport Injury.....................................................................................13 Models and Theories of Sport Injury .............................................................14 v Responses to Sport Injury Research.....................................................................22 Emotional Responses .....................................................................................13 Coping Strategies ...........................................................................................25 Growth Research ..................................................................................................27 Models and Theories of Growth.....................................................................29 Growth Research ............................................................................................33 Sport Injury and Growth.......................................................................................35 Summary and Recommendation for Future Research................................................39 Chapter 3: A Grounded Theory of Sport Injury-Related Growth .............................43 Abstract ......................................................................................................................44 Introduction ................................................................................................................45 Methods......................................................................................................................49 Philosophical Orientation and Methodology........................................................49 Participants...........................................................................................................50 Data Collection and Procedure.............................................................................51 Data Analysis .......................................................................................................53 Results........................................................................................................................56 Sport Injury...........................................................................................................57 Meta-Cognition and Positive Reappraisal............................................................58 Positive Emotions and Facilitative Responses.....................................................59 Internal Resources................................................................................................63 External Resources...............................................................................................65 vi Sport Injury-Related Growth................................................................................69 Discussion ..................................................................................................................71 Chapter 4: Interventions to Promote Growth Following Adversity: A Systematic Review of Evidence-Based Practice (Study 2)...............................................................78 Abstract ......................................................................................................................79 Introduction ................................................................................................................80 Methods......................................................................................................................82 Design...................................................................................................................82 Inclusion Criteria..................................................................................................82 Search Strategy.....................................................................................................83 Shifting of Research Papers .................................................................................84 Results........................................................................................................................86 Emotional Processing Interventions.....................................................................86 Cognitive Techniques Interventions...................................................................103 Combined Techniques Interventions..................................................................107 Qualitative Interventions....................................................................................109 Discussion ................................................................................................................112 Chapter 5: Practice-Based Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists...................................123 Abstract ....................................................................................................................124 Introduction ..............................................................................................................125 vii Methods....................................................................................................................128 Design and Assumptions....................................................................................128 Sampling Procedure and Participants.................................................................128 Interview Guide..................................................................................................130 Data Analysis .....................................................................................................132 Results......................................................................................................................133 Reactionary Phase ..............................................................................................133 Preparation Phase ...............................................................................................138 Reflection Phase .................................................................................................141 Application Phase...............................................................................................144 Monitoring Phase ...............................................................................................149 Influential Factors of SIRG ................................................................................151 Athlete’s Personality ....................................................................................152 Team Environment/Culture..........................................................................154 Social Support Network ...............................................................................156 Athlete’s Free Time......................................................................................158 Discussion ................................................................................................................160 Chapter 6: General Discussion and Conclusions……………………………………168 Introduction ..............................................................................................................169 Summary of Studies ...........................................................................................169 Study 1: A Grounded Theory of Sport Injury-Related Growth..........................170 viii Study 2: Evidence Based Interventions to Promote Growth Following Adversity: A Systematic Review......................................................171 Study 3: Practice-Based Evidence of Facilitating Sport InjuryRelated Growth: Phases and Strategies Recommended by Sport Psychologists......................................................................................................172 Synthesis of Results Across Studies……………………………………………….173 Theoretical and Empirical Impact of this Thesis......................................................175 Theoretical Impact..............................................................................................175 Empirical Impact ................................................................................................179 Practical Implications...............................................................................................181 Strengths and Limitations.........................................................................................187 Future Research Recommendations.........................................................................188 Overall Conclusions.................................................................................................190 References.......................................................................................................................192 Appendices......................................................................................................................227 ix Publications and Presentations Journal Publications Roy-Davis, K., Wadey, R., & Evans, L. (2017). A grounded theory of sport injury-related growth. Sport, Exercise, and Performance Psychology, 6(1), 35-52. DOI: 10.1037/spy0000080 Conference Presentations Roy-Davis, K., Wadey, R.m & Evans, L. (2017). Practice-Based Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists. Poster session to be presented at the 2017 Association for Applied Sport Psychology (AASP) 32nd Annual Conference, Orlando, USA. x Appendices Page Appendix A. Participant consent form- Study 1..................................................................228 B. Participant debrief form- Study 1 ..................................................................231 C. Participant information sheet- Study 1 ..........................................................214 D. Interview Guide- Study 1...............................................................................236 E. Participant consent form- Study 3..................................................................243 F. Participant debrief form- Study 3 ..................................................................246 G. Interview Guide- Study 3...............................................................................249 xi Tables Table 1. Qualitative Assessment for Quantitative Studies ................................................88 Table 2. Emotional Processing Interventions ....................................................................91 Table 3. Cognitive Interventions....................................................................................... 93 Table 4. Combined Interventions...................................................................................... 96 Table 5. Qualitative Interventions..................................................................................... 97 Table 6. Measures of Growth used in Interventions: Abbreviations and Full Titles.........98 Table 7. Sport Psychologist’s Overall Strategies and Skills............................................145 Table 8. Sport Psychologist’s Overall Tools ...................................................................147 xii Figures Figure 1. Wiese-Bjornstal, D., Smith, A., Shaffer, S., & Morrey, M. (1998). An integrated model of response to sport injury: Psychological and sociological dynamics. Journal of Applied Sport Psychology, 10, 46-68 .........................16 Figure 2. Brewer, B., Andersen, M, & Van Raalte, J. (2002). Psychological aspects of sport injury rehabilitation: Toward a biopsychosocial approach. In D. Mostofsky & L. Zaichkowsky (Eds.). Medical and psychological aspects of sport and exercise, (pp. 44-54). Morgantown, West Virginia: Fitness Information Technology ....................................................................................................19 Figure 3. Kubler-Ross, E. (2009). On death and dying: What the dying have to teach doctors, nurses, clergy and their own families. London, United Kingdom: Taylor & Francis...............................................................................................21 Figure 4. Tedeschi, R., & Calhoun, L. (1995). Trauma and transformation: Growing in the aftermath of suffering. Thousand Oaks, CA: Sage Publications..............30 Figure 5. Roy-Davis, K., Wadey, R., & Evans, L. (2017). A grounded theory of sport injury-related growth. Sport, Exercise, and Performance Psychology, 6(1), 35-52..........................................................................................................................56 Figure 6. Shifting of researcher papers..............................................................................85 Figure 7. Conceptual Model of the Development of Sport Injury-Related Growth .......................................................................................................................................................135 xiii Acknowledgments First and foremost, I want to thank my supervisors, Dr. Ross Wadey and Dr. Lynne Evans, as well as my Director of Studies, Dr. Ceri Diss for their continuous support and encouragement during this thesis. I cannot express enough how much I appreciate your time and attention. Thank you for giving me this wonderful opportunity. Particularly Ross, thank you for your guidance and for being a truly wonderful supervisor. A very special thank you to my family. Mom, you have always been my biggest cheerleader and believed in me when I didn’t believe in myself. Grandma and Grandpa, thank you for your enthusiasm, and I’m sorry that I’ve been away for so long. To the rest of my family, thank you for your love and understanding. Thank you to all my friends, both in the U.K. and U.S.A. You’re all amazing, beautiful people and you’ve helped me so much whether you knew it or not. To my fellow PhD candidates, thank you for the happy memories I’ll take with me. It was great sharing this journey with you. I would also like to thank all my participants. I truly appreciate that you gave me your time and shared your stories. This thesis would not exist without you. Lastly, thank you to Adam. You’re the best friend and husband I could ask for. You’re my rock. 1 Chapter 1: Introduction 2 What is this PhD about? The aim of this Ph.D. was to better understand the sport injury experience, particularly how sport injury may actually provide beneficial aspects, commonly referred to as “growth”, for athletes who have sustained injury. More specifically, this programme of research sought to provide practical information that may further assist individuals who work with injured athletes in an applied manner. Through the use of qualitative research and systematic review, this thesis explored the sport injury experience as well as the promotion of growth for injured athletes. The purpose of the first study, A Grounded Theory of Sport Injury-Related Growth, was to develop a context-specific theory pertaining to the development of growth following a sport injury. The second study, Interventions to Promote Growth Following Adversity: A Systematic Review of EvidenceBased Practice, used a systematic review methodology to explore interventions that have been used to promote growth for traumatized populations. The final study, PracticeBased Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists, investigated the experiences and expertise of sport psychologists who have worked with injured athletes in order to further comprehend the issues surrounding growth cultivation in a practical setting. Collectively, these three studies have helped to advance the knowledge of sport injury, in particular the ways in which growth may be developed as a result of a sport-related injury. Background The topic of sport injury has long since been an interest of mine, however, I was always drawn to the field of psychology. Fortunately, despite a lifetime of involvement in 3 sport and physical activity I never experienced a significant sport injury, yet I would constantly see friends and teammates struggle through an injury they had sustained through sport. I knew that I wanted to help them, but I did not know how. Although I would often try to help alleviate the burden of their injury, I could see the toll their injury was having on them, not just physically but mentally and emotionally as well. In the days before I even began this Ph.D., when I was still trying to figure out what a thesis was and what mine may look like I met with Dr. Ross Wadey. During this meeting he told me about his idea for a programme of research that would begin with the development of a theory related to sport injury-related growth. Although I was vaguely familiar with the concept of post-traumatic growth, I had not yet seen this concept related to sport injury. This quickly sparked a change in my perception of sport injury- the idea that athletes may actually return to their sport better than they were before their injury. This idea went beyond exciting me; it felt right to me and I could immediately see the contribution this research could have for the field of sport injury. Suddenly, I was seeing sport injuries differently. While it was, and is still, my opinion that sport injury will never be a good thing- no one wants to be injured- but maybe for those unlucky ones who do get injured, my research could help these athletes be a little less unlucky. Maybe sport injuries did not have to be this terrible, debilitative thing. Maybe sport injuries could become an experience that helps athletes. Rather than muddling through their recovery, injured athletes could potentially be guided to achievements they had never reached before or change in ways that will positively affect them. This created not only a personal revelation, but also became the inspiration and focus for my Ph.D. 4 Conducting Research Although I knew that the general idea driving my thesis was exploring the concept of growth following sport injury, specifically with the aim of creating a contextspecific theory, I needed to decide how this aim would be achieved. Immediately I knew that this first research effort would be a qualitative nature, a methodology I had become familiar with during my undergraduate and graduate studies, but had never personally undertaken. From my time as a student before starting this Ph.D., I knew that research could be of either a qualitative or qualitative nature, or, in some instances, a mixture of the two. I had conducted quantitative research as a Masters student, and can appreciate the satisfaction questionnaires and a numerical value can bring. However, as someone who hesitates around numbers and gravitates towards stories, I knew that my real interest was in qualitative research. While I was confident that I could rise to the personal challenge a numbers-based study, I instinctively knew that I wanted more than that- I wanted the story beyond the statistics. I wanted to discover and explore the feelings and experiences of these athletes, and wholeheartedly embraced the qualitative approach. Despite my tendency to reduce research methodology to its most basic elements (i.e., quantitative research is numbers, qualitative research is words), this does not fully encapsulate the qualitative research approach. Indeed, the term “qualitative research” lacks a clear definition, and is often defined as simply being the counterpoint to quantitative research (Martin, 2011). Qualitative research does, however, hold common characteristics, such as its search for meanings, subjectivity, context, and reflexivity (Sparkes & Smith, 2014). So while quantitative research is focused on measuring facts and explaining the relationship between these facts in a technical manner, the goal of 5 qualitative research is to gain understanding of how people experience and make sense of the world (Smith & Caddick, 2012). I knew that this was the research I wanted to conduct and I began to familiarize myself with different qualitative approaches, namely the grounded theory methodology, as I knew this would be the research methodology of my first study. What I was unaware of at this point, was the importance of determining my own views of ontology and epistemology. A bit bewildered at first- wasn’t I studying psychology, not philosophy? I soon realized the significance of these concepts and the relationship between personal viewpoints and research design. So rather than rustling up an interview guide and diving into date collection as I had initially imagined, I found myself pondering on various philosophical ideals and reflecting on my own interpretations of reality and knowledge. Eventually, and with much deliberation, I decided my personal beliefs were those of a post-positivist with critical realism and modified dualism/objectivism. To elaborate, critical realism refers to the idea that the reality that humans perceive is influenced by unobservable events and it is only through attempting to understand these events that we are able to comprehend the social world. Modified dualism/objectivism refers to my belief that as a researcher, it is my duty to make efforts to minimize any effect my presence may have on the research process. Upon deciding these views, I could begin to plan and conduct my research accordingly. Throughout this programme of study, as I progressed through my research and decided on the ensuing steps to be taken, I would constantly question whether the research I was designing and analyzing aligned with my personal beliefs. These beliefs have important 6 implications, as my personal assumptions influenced how I approached and conducted the research within this thesis. Overview of the Thesis This dissertation consists of six chapters in total, and contains three original studies. This introduction serves as the first chapter and is presented for the purpose of providing clarity and to prime the reader for the forthcoming chapters. Following this Introduction, Chapter II, Literature Review, is presented to provide a critical review and synthesis of the current literature related to the areas of responses to sport injury, growth research, and sport injury and growth. Specifically, the aims of this chapter are to (a) provide information on the existent research pertaining to sport injury as well as the models and theories of sport injury; (b) review the research related to the emotional responses of athletes upon sustaining injury, and the reported coping strategies these athletes subsequently employ; (c) present and explain the concept of growth following a traumatic or stressful event, including descriptions and critical appraisals of models and theories of growth, as well as describing and critically reviewing prominent growth research; (d) draw together the concepts of sport injury and growth by explaining and critically appraising research that has focused on this area; and (e) summarize the information presented in this chapter and provide recommendations for future research, before concluding with the aims and rationale for this programme of research. Chapter III, A Grounded Theory of Sport Injury-Related Growth, reports results from Study 1, which aimed to develop a context-specific theory of growth following a sport injury by exploring the experiences of injured athletes who perceived a degree of 7 growth from their own injury. A grounded theory methodology was conducted, with 37 injured athletes taking part and providing a total of 70 interviews collected through the use of semi-structured interviews. After each interview, the data was transcribed and analyzed using a method of open, axial, and selective coding. Findings reveal that injured athletes are able to experience the development of growth through the mechanisms of metacognition, positive reappraisal, positive emotions, and facilitative responses. These mechanisms are influenced by the presence of a combination of internal and external factors, which if support the development of growth, will positively affect the athlete and result in a perception of injury has holding inherent opportunities. This theory provides greater insight into the injury experience, particularly the role and occurrence of growth related to sport injury, illuminating why some athletes may be able to experience the development of growth while others are not. However, this study did not provide information on how this growth process may be encouraged in an applied setting, and therefore the aim for the following study focused on delving into the topic of specific interventions that may successfully promote growth. Chapter IV, Interventions to Promote Growth Adversity: A Systematic Review of Evidence-Based Practice, gives a description and the results from the second study of this thesis. This study used a systematic review methodology to investigate the use of interventions that have demonstrated success in promoting post-traumatic growth. As the ultimate goal for this thesis is to provide information that will aid applied practitioners working with injured athletes, the desired research question at the commencement of this study was to focus on research conducted regarding post-traumatic growth and sport injury. However, as this is a relatively new area of research and there is insufficient, if 8 any, existent literature that addresses this research question, the goal of this review shifted to concentrate on any intervention-based research conducted with the goal of fostering growth for a population that had experienced a stressful or traumatic event. In total, 37 studies were identified that met the pre-determined inclusion criteria. These 37 interventions fell into 4 categories: (a) emotional processing- seeking to provide the participant with a sense of closure, catharsis, or fulfillment; (b) cognitive strategieswhich attempt to bestow participants with the relevant tools to aid the post-traumatic growth process; (c) combined technique- interventions that drew upon both emotional and cognitive processing techniques; and (d) qualitative interventions- studies which used interventions aimed at promoting growth but focused on gaining rich, in-depth information gathered through interviews and observations. Among the studies that successfully demonstrated the encouragement of growth, the researchers either identified or suggested that these interventions were able to foster growth through the mechanisms of cognitive restructuring and/or reappraisal. This review also identified that both the duration of the intervention and the timing of the intervention implementation after the traumatic event are important considerations. These findings illuminate certain methods through which growth may be better encouraged yet these studies did not focus on promoting growth for injured athletes. The need to further understand the process of urging growth for injured athletes provided the rationale for the following study. Chapter V, Practice-Based Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists, explains the procedure and results of the final study in this programme of research. The goal of this study was to gather information about the real-world experiences of sport psychologists who work 9 with injured athletes in a practical setting. In particular, this research sought to explore any issues related to the promotion of growth for applied practitioner working with injured athletes and investigate how these practitioners have been able to successfully encourage growth for injured athletes. This study specifically decided to use sport psychologists for participants, as these individuals were more likely to be familiar with the concepts of post-traumatic growth and therefore provide richer, more in-depth data. Ten sport psychologists were purposively selected for their expertise and experiential knowledge and data was gathered through the use of semi-structured interviews. Analysis of the data revealed that the sport psychologists were able to encourage growth by effectively guiding the injured athlete through a fluid developmental framework. This framework consists of five phases: (a) reactionary phase, (b) preparation phase, (c) reflection phase, (d) application phase, and (e) monitoring phase. The sport psychologists also reported using a variety of specific strategies, skills, and tools that would be employed to match the current needs of the athletes. Finally, a number of personal and environmental factors were identified that either promoted or hindered the development of growth. These results offer useful information to applied practitioners and in this way extend the previous research. Chapter VI, General Discussion and Conclusions, is the final chapter and brings this dissertation to a close by summarizing the three studies and discussing their contribution to knowledge. After this review of the three original studies and their results, this chapter concentrates of the theoretical and empirical impact, as well as the practical implication of this research. Thereafter, the strengths and limitations of this thesis are 10 discussed and recommendations for avenues of future research are presented. Finally, the central aspects of this programme of research are drawn together in an overall conclusion. 11 Chapter 2: Literature Review 12 Abstract The purpose of this chapter was to provide a critical review of the psychology of sport injury literature, the concept of growth following adversity, and recent research that has aimed to integrate these two bodies of literature Specifically, this reviews describes a model, theories, and research related to the psychological response to sport injury, namely the integrated model of response to sport injury developed by Wiese-Bjornstal, Smith, Shaffer, and Morrey (1998). It also synthesizes the literature related to models, theories and research on post-traumatic growth. Lastly, it draws these two concepts together in the context of growth following a sport injury. The review considers both conceptual and methodological issues across the bodies of literature. The chapter concludes with a summary and recommendations for areas of future research. 13 Introduction The purpose of this chapter is to provide a critical review of the research related to the concepts of sport injury and growth following adversity as a basis for the rationale for this programme of research. The chapter has been divided into four sections: Responses to Sport Injury, Growth Following Adversity, Sport Injury and Growth, and Summary. The first section, Response to Sport Injury, will synthesize the research into athletes’ psychological responses to sport injury. The second section, Growth Following Adversity, will explore the literature related to benefits associated with undergoing a traumatic or stressful event across a variety of populations and types of stressful events. The third section, Sport Injury and Growth, will examine the research relating to the benefits derived from experiencing a sport-based injury. This review has been separated so as to introduce the reader first to the topic of Responses to Sport Injury, as this is considered the primary concept of this sport psychology-based thesis. However, this thesis is also concerned with the field of post-traumatic growth and therefore the following section, Growth Following Adversity, helps facilitate knowledge translation between other fields of research and sport psychology by contextualizing growth following sport injury and the large body of research exploring growth following adversity. Finally, to draw these two fields together, the third section, Sport Injury and Growth, provides a contextualized understanding of growth within the context of sport injury. The fourth and final section will provide a summary of the chapter and recommendations for future research. Responses to Sport Injury Although research into the psychology of sport injury dates back to the 1960’s, 14 the majority of it has been conducted over the last 20 years. Findings in this field have indicated that athletes who have sustained injury undergo cognitive, emotional, and behavioural changes, the majority of which have been considered unpleasant in nature (Evans, Mitchell, & Jones, 2006). Indeed, injury has been viewed as a largely negative experience characterized by heightened levels of depression, frustration, and helplessness (e.g., Evans & Hardy, 1995; Leddy, Lambert, & Ogles, 1994). Where positive effects of injury were reported they emerged serendipitously (e.g., Bianco, Malo, & Orlick, 1999; Ford & Gordon, 1999; Hurley, Moran, & Guerin, 2007; Podlog & Eklund, 2006; San Jose, 2003; Tracey, 2003). However, in recent years, researchers have begun to investigate positive consequences related to sport injury (e.g., Udry, Gould, Bridges, & Beck, 1997) encouraging a shift to a more inclusive view of the injury experience (Wadey, Evans, Evans, & Mitchell, 2011), wherein both negative and positive experiences are considered. Unfortunately, to date these studies have been somewhat solitary in nature, and not provided a focused, systematic approach to this important line of enquiry. A more inclusive view of the research to date, suggests that injured athletes report both negative (i.e., anxiety) and positive (i.e., increased resilience) responses, suggesting that injury may not be an inherently a negative experience as originally conceived. Indeed, contrary to the prevailing belief that injury is a largely negative experience, in recent years research has highlighted the ways in which athletes are able to benefit from their injury and even experience a degree of growth as a result of it (e.g., Galli & Vealey, 2008; Podlog & Eklund, 2006; Tracey, 2011; Udry et al., 1997; Wadey et al., 2011; Wadey, Evans, Hanton, & Neil, 2012). 15 Models and Theories of Sport Injury As the field of sport injury research has grown, researchers have endeavored to provide explanations of the injury experience and the underlying processes through the development and application of various models and theories. These models and theories include the integrated model of response to sport injury (Wiese-Bjornstal, Smith, Shaffer, & Morrey, 1998), biopsychosocial model of sport injury rehabilitation (Brewer, 2003), stage-based grief response models (Kubler-Ross, 2009), self-determination theory (Deci & Ryan, 2011), cognitive-motivational relational theory of emotion (Lazarus, 2000), selfefficacy theory (Bandura, 1994), reversal theory (Apter, 1989), personal investment theory (Maehr, & Braskamp, 1986), and protection motivation theory (Rogers, & Prentice-Dunn, 1997). The first three of these - the integrated model of response to sport injury, the biopsychosocial model of sport injury rehabilitation, and the stage-based grief response - will now be discussed, as these are typically the most adopted within the sport injury research. Indeed, the factors and processes identified by these models, and theory, have also been identified in research pertaining to post-traumatic growth; in this way, these models and theory show promise for making connections between the fields of sport injury and growth following adversity. Of particular importance to this programme of research, is the integrated model of response to sport injury (Wiese-Bjornstal et al., 1998), as this model has received the most empirical support to date (Wadey & evans, 2011), and has served as the foundation for this thesis. Although each model and theory has specific strengths, the model that has received the most attention in the literature is the integrated model of response to sport injury (Wiese-Bjornstal et al., 1998). According to this model (see Figure 1), a 16 Stress Response Sport Injury History of Stressors Coping Resources Intervention Personal Factors Situational Factors Cognitive Appraisal Goal adjustment Rate of perceived recovery Self-perceptions Beliefs and attributes Sense of loss or relief Cognitive coping Injury History Severity Type Perceived cause Recovery status Individual Differences Psychological Personality Self-perception Self-motivation Motivational orientation Pain tolerance Athletic identity Coping skills Psychological skills History of stressors Mood states Demographic Gender Age Ethnicity Socioeconomic status Prior sport experience Physical Ergogenic aids Physical health status Disordered eating Sport Type Level of competition Time in season Playing status Practice vs. game Scholarship status Social Teammate influences Coach influences Family dynamics Sports medicine team influences Social support provision Sport ethic/philosophy Environmental Rehabilitation environment Accessibility to rehabilitation Behavioural Response Adherence to rehabilitation Use of PST strategies Use/disuse of social support Risk taking behaviours Effort and intensity Malingering Behavioural coping Emotional Response Fear of unknown Tension, anger, depression Frustration, boredom Positive attitude/outlook Grief Emotional coping Recovery Outcomes -Psychosocial -Physical Figure 1. Wiese-Bjornstal Integrated Model of Response to Sport Injury 17 combination of pre-injury and post-injury variables influence an athlete’s responses to injury and their ensuing recovery outcome. Factors such as personality (e.g., perfectionism), history of stressors (e.g., previous injury/injuries), coping resources (e.g., psychological skills), and interventions (e.g., stress management) comprise the pre-injury variables. Post-injury variables include personal factors (e.g., severity of injury) and situational factors (e.g., time of competitive season). These factors influence an athlete’s cognitive appraisal of their injury and rehabilitation, and their emotional and behavioural responses, and recovery outcome. For example, a runner who has incurred his second knee injury three months before the start of the competitive season, experienced this injury previously (i.e., personal factor/history of stressors), but has sufficient time before the season begins (i.e., situational factors), might have a positive attitude about making a full recovery (i.e., cognitive and emotional response). This in turn could affect his adherence to his rehabilitation programme (i.e., behavioural response), resulting in a shorter, more successful recovery process and returning to competition at an equivalent, or even higher level of functioning than previously (i.e., recovery outcome). In this instance, an athlete may exhibit signs of growth resulting the injury. This model, although well-developed and widely used, however, does not provide a detailed explanation of the mechanisms through which athletes may experience the full range of possible recovery outcomes. More recently, Brewer (2003) developed the biopsychosocial model (see Figure 2), which integrates the frameworks of existing models of sport injury rehabilitation (e.g., Wiese-Bjornstal et al., 1998) with more general models of health outcomes (e.g., Cohen & Rodriguez, 1995). The biopsychosocial model is comprised of seven dimensions: 18 injury characteristics, sociodemographic factors, biological factors, social and contextual factors, intermediate biopsychological outcomes, and sport injury rehabilitation outcomes. In this model, injury characteristics refers to the nature of the injury (e.g., type, location, severity, history), which together with the individual’s sociodemographic factors (e.g., age, gender, race/ethnicity, and socioeconomic status) will influence the biological (e.g., immune functioning), psychological (e.g., personality), and social/contextual (e.g., life stress) factors. These three factors will subsequently affect the intermediate biopsychological outcomes, such as range of motion, strength, pain, and recovery rate. Finally, these intermediate outcomes will influence the rehabilitation outcomes, for example, functional performance, quality of life post-injury, treatment satisfaction, and desire and readiness to return to sport. Within this model, psychological factors play a unique, central role, having a direct bidirectional relationship with biological and socio-contextual factors, and the resulting intermediate and final recovery outcomes. While this model provides a holistic framework that helps to explain the process of sport injury rehabilitation, it does not offer an explanation of the relationships between the specific psychological variables. Prior to models that were specifically developed in a sport injury context, sport injury research often drew upon the stage-based grief model developed by Kubler-Ross (2009). This model (see Figure 3), which was derived to explain the emotional experiences of the terminally ill, postulates that grieving individuals will experience five stages: shock and denial, anger, bargaining, depression, and acceptance. Shock and denial, the first stage, is characterised by an individual’s failure to accept their current situation. This denial is reported to function as a buffer, affording the individual time to 19 Psychological Factors - Personality - Affect - Behaviour Injury Characteristics - Type - Location - Antecedents (history) - Cause - Severity Socio-demographic Characteristics - Age - Gender - Race/ethnicity - Socio-economic status Biological Factors - Endocrine - Respiration - Metabolism - Tissue repair - Sleep - Nutrition - Circulation - Immune functioning - Neurochemistry Social/contextual Factors - Social network - Life stress - Situational characteristics - Rehabilitation environment Biopsychological Intermediate Outcomes - Range of motion - Strength - Endurance - Joint elasticity - Rate of recovery - Pain Sport Injury Rehabilitation Outcomes - Functional performance - Quality of life - Satisfaction of treatment - Readiness to return to sport Figure 2. Biopsychosocial Model. 20 begin mobilising psychological defences. The second stage is characterised by anger, which is directed either externally (e.g., coach) or internally (i.e., self) and is fuelled by a sense of betrayal. Next, a stage of bargaining, is marked by the individual attempting to find a sense of resolution by offering pledges; this part of the process is typically kept secret or only shared with those the individual deems trustworthy. A period of depression follows, marked by symptoms such as social withdrawal, hopelessness, and unproductiveness. This depressive stage appears to be the longest period within the grief process and is considered to serve as a tool to facilitate acceptance of the impending loss. In the final stage of acceptance, they acknowledge their loss and its consequences. While reaching this stage does not denote a sense of happiness, it does signify the completion of the individual’s progression through the grieving process. Although developed for a different population, sport injury researchers have argued the applicability of grief to an athletic population, positing that athletes’ exhibit a comparable grief response upon sustaining injury (Evans & Hardy, 1995). This grief is postulated to be due to the significant personal loss that occurs as the result of the injury and the interruption it causes to an athlete’s investment in their training and sport participation (Brewer, 1999; Van Der Poel, J., & Nel, P., 2011). However, a number of researchers have questioned the relevance of this model to the sports injury process, not least because of the impermanent nature of most injuries (Rose & Jevne, 1993; Udry et al., 1998). The strengths of the integrated model of sport injury response and the biopsychosial model are that they were developed for sport injury and so are contextual to this field of research (e.g., Brewer et al., 2002; Wiese-Bjornstal et al., 1998). Likewise, the Kubler-Ross stage-based model of grief provides insight into the process that injured 21 Figure 3, Kubler-Ross Stages of Grief Model athletes may face, particularly when the potential for loss if great and their identity as an athlete is threatened. Although these models, alongside others not discussed within this literature review, have aided our knowledge and understanding of specific concepts in an injury context, they are limited in describing and explaining certain phenomena. These limitations include firstly, a failure to define, delimit, and describe specific recovery outcomes, which is essential for elucidating the recovery process and associated outcomes. Also, across these models and theories is a failure to explain the mechanisms for attaining certain recovery outcomes. For example, are there different processes for different recovery outcomes? It is important to ascertain these mechanisms to guide future research and theory development. Finally, the models described above were not Time Process Denial Anger Depression Bargaining Acceptance 22 designed to direct interventions. Indeed, models need to bridge the gap between theory and practice. For example, what interventions should practitioners use to help foster desirable, and prevent undesirable, recovery outcomes? Responses to Sport Injury Research Upon sustaining an injury, athletes are likely to experience a range of emotional, cognitive, and behavioural responses (Evan, Mitchell, & Jones, 2006). As discussed in the previous section, a number of models regarding the response to and rehabilitation from sport injury have been proposed in the sport injury literature. The model that has received the most attention in the response to sport injury research is the integrated model of response to sport injury developed by Wiese-Bjornstal et al. (1998). Researchers have focused on various aspects described in the model including: cognitive appraisal (e.g., Albinson & Petrie, 2003; Chung, 2012; Daly, Brewer, Van-Raalte, Petitpas, & Sklar, 1995; Ruddock-Hudson, O’Halloran, & Murphy, 2012; Weiss & Ebbeck, 1996), social support (e.g., Abgarov, Jeffrey-Tosoni, Baker, & Fraser-Thomas, 2012; Mitchell, 2011; Rees, Mitchell, Evans, & Hardy, 2010; Rees, Smith, & Sparkes, 2003), psychological skills (e.g., Hare, Evans, & Carlow, 2008; Nordin-Bates et al., 2011; Wesch et al., 2012), adherence to rehabilitation (e.g., Marshall, Donovan-Hall, & Ryall, 2012), interventions (e.g., Rock & Jones, 2010), recovery outcomes (e.g., Brewer, 2010), and a number of personal (e.g., athletic identity; Brewer, Cornelius, & Van Raalte, 2010) and situational factors (e.g., timing of injury; Gayman & Crossman, 2003). As it is beyond the scope of this review to examine the research pertaining to each of these variables, the following sections will provide a critical discussion of injured athletes’ emotional responses and coping attempts, as these concepts are germane to this thesis and are prominently featured 23 in both the literature regarding sport injury responses as well as the literature regarding post-traumatic growth. Emotional responses. The initial period following injury occurrence is typically characterized by negative feelings, such as frustration, anger, and depression (e.g., Clement, Arvinen-Barrow, & Fetty, 2015). For example, Mainwaring et al.’s (2004) reported a significant spike in depression, confusion, and total mood disturbance in athletes immediately after injury occurrence; emotions that subsided three weeks after injury, as the athletes began to cope with their situation. To better understand the reactions related to sport injury, Udry et al. (1998) interviewed 21 elite skiers about their responses after sustaining season-ending injuries. In total, 136 psychological reactions were identified and categorized into four dimensions: injury-relevant information processing-awareness (e.g., questioning), emotional upheaval/reactive behaviour (e.g., emotional agitation), positive outlook/coping attempts (e.g., good attitude/optimism) and other (e.g., ambivalence). These results further highlight the temporal nature of psychological reactions to injury, as athletes demonstrated a need to first process their injury-relevant information before responding emotionally. However, the aim of this study was not to determine the temporal sequence of psychological reactions, but to investigate the range of responses that occur. This concept supports, and extends, the findings of Quackenbush and Crossman (1994) who surveyed 25 injured athletes and identified 48 emotional reactions related to the injury experience. Of these 48 reported emotions, 36 were positive (e.g., hopeful) and 12 were negative (e.g., frustrated), and likewise displayed a temporal element, with negative emotions decreasing over time and positive emotions increasing. 24 Subsequent studies further suggest that athletes’ emotions are likely to shift and become more positive as they progress through their recovery (e.g., Madrigal & Gill, 2014). However, injury onset is generally found to be associated with the experience of numerous negative emotions such as fear, anger, or depression (Faris, 1985). Rehabilitation is typically characterized as a period that includes discouragement, frustration, and isolation, while return to sport is associated with emotions such as impatience, anxiety, anticipation, and increased confidence (e.g., Bianco, 2001; Granito, 2001; Johnston & Carroll, 1998). In Tracey’s (2003) exploration of college athletes’ recovery from moderate to severe injuries, results showed that emotions fluctuated in the time after injury, characterized by feelings of loss, lowered self-esteem, anger, and frustration. Over time, however, athletes’ view of their injury began to evolve and injury was instead perceived as a challenge and was approached with a positive attitude. Ultimately, these athletes acknowledged that their injury and rehabilitation was a process that facilitated greater self-understanding (e.g., inner strength) and appreciation (e.g., not taking health for granted). Ruddock-Hudson et al., (2014) investigated the emotional reactions of Australian League Football players and found that the severity of the injury appears to moderate athletes’ emotional reactions, with minor and severe and/or long-term injuries showing distinct emotional variations. Minor injuries seem to present little concern or limitations for athletes and so are responded to more positively and optimistically. Conversely, longterm injuries, such as knee reconstructions, invoke negative emotional responses and are viewed as more challenging. Social support is another factor that moderates emotional responses to sport injury, however, this effect diminishes with minor injuries. 25 Coping strategies. Sport injury is an experience associated with a high degree of strain, leading researchers to focus on the coping strategies used by injured athletes during injury onset, rehabilitation, and return to sport (e.g., Evans, Wadey, Hanton, & Mitchell, 2012). Coping is defined as the “constantly changing cognitive and behavioural efforts to manage specific external and/or internal demands that are appraised as taxing or exceeding the resources of the person” (Lazarus & Folkman, 1984, p. 141). Just as athletes experience a range of emotional responses as a result of a sport injury, they draw upon a variety of coping strategies, specifically, emotion- or problem- focused. Emotionfocused coping strategies aim to manage the negative emotions associated with the stressor (e.g., emotional disclosure). Problem-focused coping strategies concentrate on tackling the stressful situation (e.g., planning). More recently, researchers have explored the use of avoidant coping (e.g, Allen, Greenlees, & Jones, 2011; Carson & Polman, 2010), which refers to strategies used to avoid the situation through distraction (e.g., cognitive distancing) or social diversion (e.g., walking away). In this way, avoidance coping strategies may facilitate control over short-term emotional states and has been observed to be a strategy regularly used by athletes to deal with acute stress during sport participation (Nicholls, Holt, Polman, & Bloomfield, 2006). However, avoidant coping is generally associated with a number of psychological and physiological outcomes and is suggested to be maladaptive long term (e.g., Kim & Duda, 2003). Other research on coping skills related to sports injury reveal that athletes seek to gather information regarding their rehabilitation to gain a better understanding on the route to recovery (Carson & Polman, 2008), a form of problem-focused coping. Instances of emotionfocused coping strategies throughout the sport injury process (e.g., Udry et al., 1998; 26 Wadey et al., 2012b) include venting of emotions, seeking emotional social support, positive self-talk, and reframing negative thoughts and emotions. The possession and employment of coping skills appear to be shaped in part by instances of past adversity (Bejar & Butryn, 2016). Being exposed to stressful events previously may enable athlete to feel better prepared to face stressors, such as sport injury. Athletes exhibit high degrees of perseverance through their participation in sport and it is speculated that this determined approach helps athletes to cope with their injury. In Albinson and Petrie’s (2003) examination in cognitive appraisals, stress, and coping after sports injury, cognitive appraisals were found to be related to the coping strategies used by injured athletes. Specifically, athletes’ primary and secondary appraisals of their injury related to their coping strategies, with athletes who scored higher in mood disturbance during this period demonstrating higher occurrences of avoidance coping techniques. Findings from this study suggest that the first week post-injury may be a crucial time-point for athletes’ appraisals, as this appraisal will influence athletes’ coping strategies throughout the remainder of their recovery. For example, athletes that utilized avoidant coping techniques at the seven-day mark after injury onset also exhibited less cognitive active coping (i.e., attempts to manage appraisal of stressful event) during subsequent assessments. This suggests that helping injured athletes to manage their cognitive appraisals will also influence their engagement in behaviour aimed at dealing with their injury and its affects. Johnston and Caroll (2000) also found a temporal element, as their results showed that coping varied as a function of stage in rehabilitation. It was also revealed that the use of coping strategies declined over the course of rehabilitation, showing that rather than 27 shifting coping strategies, athletes’ use of coping declined overall as they progressed through recovery. Furthermore, coping appeared to be a stable characteristic of individuals, with no clear situational-specific coping strategy emerged from the data. However, results did demonstrate that participants preferred informational and emotional support in the middle and towards the end of their rehabilitation rather than at the beginning. This may be due to the athletes in their study being less receptive and regarding these types of support to be unnecessary during injury onset to deal with the intense emotions that characterize it. Growth Research Historically, both research and anecdotal evidence has postulated how personal gain can be derived from experiences of overcoming adversity (Joseph & Linley, 2004). However, it has not been until recently that growth following adversity has been studied with empirical and theoretical rigor (e.g., Calhoun & Tedeschi, 2006; Carver, 1998; Heffernon, Grealy, & Mutrie, 2009; Joseph & Linley, 2008; Weiss & Berger, 2010). Growth, defined as the perceived positive change that elevates a person to a higher level of functioning after enduring a stressful or distressing event (e.g., Kampman, Heffernon, Wilson, & Beale, 2015), can be personal (e.g., greater appreciation), psychological (e.g., increased confidence), social (e.g., strengthened relationships), and/or behavioural (e.g., improved coping skills) (e.g., Heffernon et al., 2009). Proposed mechanisms that support, or hinder, the development of growth include deliberate rumination, meaning-making, and social support (Tedeschi & Calhoun, 2004). Growth may also be explained through the prism of mindsets (Dweck, 2006; 2007; 2012). According to Dweck, individuals lie on a spectrum between either a fixed 28 mindset or a growth mindset. Those who lie closer to the end of fixed mindsets believe that each person has a finite amount of un-increasable intelli

Master of Education Master of Education by Larry W. Maguire August, 1969 UOllJU!l{llli M '11.mqlU9(f3 ~}1~no3 atVJS ao~!'l98M 194-0 A.J•.aqn APPROVED FOR THE GRADUATE FACULTY ________________________________ Everett A. Irish, COMMITTEE CHAIRMAN _________________________________ Stanley A. Sorenson _________________________________ Dohn Miller ACKNOWLEDGEMENT The writer wishes to extend his gratitude to Dr. Everett Irish for his advice and for serving as Chairman of the Graduate Committee. Appre ciation is also expressed to Dr. Dohn Miller and Mr. Stanley Sorenson for their aid and for serving on the Graduate Committee. I am most grateful to my family for their encouragement and patience. TABLE OF CONTENTS Chapter 1. 2. 3. THE PROBLEM AND DEFINITION OF TERMS • THE PROBLEM • Statement of the Problem Importance of the Study • Limitations of the Study • Overview of the Pa per DEFINITION OF TERMS REVIEW OF LITERATURE • DEFINITION, TREATMENT, AND REHABILITATION • DEFINITION Contusions • Minor Ligament Strains • Ligament Tear • Anterior Cruciate Integrity • The Retropatellar Fat-Pad Prepatellar Bursitis TREATMENT • REHABILITATION Page 1 2 2 3 3 4 5 7 16 16 18 18 19 20 21 21 23 26 4. SUMMARY AND RECOMMENDATIONS • 31 v Chapter BIBLIOGRAPHY APPENDIX • Page 34 37 Chapter 1 THE PROBLEM AND DEFINITION OF TERMS Knee injuries are probably the most common of all athletic injuries. They are almost as common in football as ankle injuries and are far more disabling. Coaches and teachers in the field of physical education and particularly athletics are indirectly responsible for the safety of their student participants in the program they are conducting. Therefore , it is imperative that educators be aware of the implications surrounding such injuries. Today, man enjoys football and other athletic events both as recreation and as competitive sports. Since the year 1933, when the first pamphlet on the prevention and care of athletic injuries was written, there has been a great many medical discoveries and advances which have increased the knowledge as to how to diagnose, treat, and rehabilitate an injury to the knee. Unfortunately, however, those educators working directly in the area of athletics, are not always aware of the implications and events leading to the possibility of injuries which occur to the athlete. In any case, the effects of the injuries are not always recognized as being factors to take into consideration when planning and implementing the athletic program. While the knee injury to the star athlete is widely 1 2 reported by the news media, and the "football knee" is so widely recog nized, no coach or instructor can be expected to be an expert in the surgical treatment of such injuries. There is, however, a need for the coach and instructor to be familiar with the problems surrounding the injury in order that precaution can be taken, and activities eliminated which pro vide for the safety of the student participant. THE PROBLEM Statement of the Problem Coaches entering the area of football need to be aware of the factors involved in knee injuries. Both experienced and inexperienced coaches can benefit from research which will enable him to adequately care for any injuries which may arise. Often coaches in athletics do not have available to them, ready information covering this problem. There fore, the purpose of this investigation was to provide relevant data per taining to all facets of the knee injury as it occurs in football; the diagnosis of the injury; prescribed treatment; qnd the actual rehabilitation of the knee. Attention will be given to these areas in hopes that the problems accom panying such an injury may be thoroughly examined and reached a better understanding. 3 Importance of the Study The value of competitive sports, especially the contact sports, is inevitably a part of our culture and is exhibited in everyday life. Injuries occur; therefore, the more knowledge that can be obtained, the better the care that can be given. In the contents that follow, this infor mation will be presented and evaluated in an effort to attain a more thorough understanding of one small phase within the scope of athletic injuries. An overall examination of the knee injury as it occurs in football and the treatment involved will be of significance to those coaches who realize the importance and the personal responsibility for being cognizant of these problems with their players. The writer developed this comprehensive overview of the knee injury problem with the intent of providing a framework of knowledge for himself as well as to other coaches and administrators who may benefit from such material for personal use. Such available data gleaned from the research of medical and educational authorities will be of value to the coach or administrator who does not have the time or facilities to pursue such an investigation. Limitations of the Study There was no attempt to compare or evaluate training or other coaching methodologies relating to the incidents of knee injuries. This research investigation was undertaken only to provide a comprehensive 4 compilation of data which could serve as a resource guide. It was not the purpose of this study to formulate conclusions based on statistical analysis of the significance or la sting effects of the knee injury. It was determined that a knowledge base regarding the care and prevention was a more worthwhile approach to the problem, rather than a mere review of cases of knee injuries taking place during the athletic sport of football. A further limitation to the study was the lack of literature provid ing a comprehensive overview of all facets of the knee injury problem. Literature on the subject was emersed in various fields of discipline as is shown in the Bibliography of this paper. Overview of the Paper Chapter 2 presents the opinions of authorities in the fields of medicine and education regarding the significance of the knee injury problem and how such injuries affect the physical and mental well-being of the injured person. The review of literature pertaining to athletic injuries was attempted in an effort to gain insight into this area of concern and also to provide rationale for the compilation of a comprehensive guide on foot ball knee injuries for use by the coach and athletic administrator. Chapter 3 is the presentation of the resource material which delineates various factors concerned in the specific knee injuries pertinent to the football player. This research data provides a basic guide for use by the coach and administrator. 5 Chapter 4 summarizes the research investigation and offers recommendations for further research. DEFINITION OF TERMS Cause of Injury Definite origin of why damage was inflicted to a part of the body. Contusions Type of bruising injury in which no tearing or breaking of the skin occurs. Rehabilitation To restore to the original state. Drawer Sign The presence of abnormal forward movement of the knee joint. Anterior Cruciate Integrity Proper functioning of knee joint through normal movements. Retropatellar Fat-Pad A pained area directly behind the knee cap due to hyperextension or a blow to this area. 6 Knee Injury Damage to the lower extremity of the leg caused by a blow, striking force, or other similar pressure. Prepatellar Bursitis Technical term for "water on the knee," which is an excess amount of fluid accumulated around an injured area. Chapter 2 REVIEW OF LITERATURE A major concern of most coaches and parents of players is the possible incidence of injury to the participant in the athletic event. Authorities in the area of physical education point to the need for coaches and other teaching personnel to cooperate with the family and community in preventing the occurrence of injury on the playing field, and providing for optimum programs in sports and athletics: ... new and imposing demands will be made on teachers and administrators. More effective coordination with medical personnel, the home, and public, semipublic, and private agencies will have to be developed • . . (2 :xi-xii) . Hirata (18:210) remarks upon the inability of the coach to assume the task of being an expert in the surgical treatment of knee injuries, or an expert in the reconstruction of permanently damaged knees. He also explains the necessity for educators to elicit the assistance of those in the medical profession and the need for schools to provide competent doctors "primarily responsible for the health of athletes in a controlled program." According to Daniels and Davies, teachers and coaches: . need to know a great deal about the structure and function of the human organism. They must understand not only normal structure and function, but also the effects of disease and injury, 7 8 and the kinds of experiences ... to remove the condition, or at least minimize its effect on total living (2:81). While the employment of a medical specialist is often beyond the financial realm of many school districts, it is conceivable to expect those educators involved in the athletic program to avail themselves of any resource person or research data which will guide them in the direction of prevention and safety. Dr. Donald B. Slocum points to the need for the coach to become aware of the manner in which injury may be incurred and the injuries most likely to occur in a given situation. He said that football presents "certain inescapable injury hazards, due to the very nature of this vigorous body contact sport" and that a knowledge of the mechanics of these injuries is vital if adequate medical history and effective diagnosis is to be made. He further states: Classifying the injuries incurred by football players has given valuable clues for prevention, diagnosis, and treatment .... Here probably the most lethal weapon in football is the oncoming knee, which exerts forces that must either be absorbed by the head or transmitted to the vertebral column (13:1640). Another member of the medical profession, Dr. Paul Trickett, Director of Athletic Medicine at Tulane University, remarks upon the psycho logical effects of the football injury. He states that while physically the injured player may recover, the trauma factor is always present and indeed increasing with the "intensity of participation" in the athletic event" (lS:iii). Therefore, it would seem that the coach and athletic trainer must 9 recognize the possible traumatic psychological effects of injuries as well as the physical implications. Trickett lists "The Bill of Rights for the College Athlete" and a review of his statements leads the reader to the realization that such a "Bill of Rights" is applicable to any coach or player from the elementary school level and higher: Participation in college athletics is a privilege involving both responsibilities and rights. The athlete has the responsibility to play fair, to give his best, to keep in training, to conduct himself with credit to his sport and his school. In turn he has the right to optimal protection against injury as this may be assured through good technical instruction, proper regulation and conditions of play, and adequate health supervision. GOOD COACHING: The importance of good coaching in protect ing the health and safety of athletes cannot be minimized. Technical instruction leading to skillful performance is a significant factor in lowering the incidence and decreasing the severity of injuries. Also, good coaching includes the discouragement of tactics, outside either the rules or the spirit of the rules, which may increase the hazard and thus the incidence of injuries. GOOD EQUIPMENT AND FACILITIES: There can be no question about the protection afforded by proper equipment and right facilities. Good equipment is now available and is being improved continually; the problem lies in the false economy of using cheap, worn-out, outmoded, or ill-fitting gear. Provision of proper areas for play and their careful maintenance are equally important. GOOD MEDICAL CARE . . . Including: FIRST •.. a thorough preseason history and physical examination. Many of the sports tragedies which occur each year are due to unrecognized health problems. Medical contraindications to partici pation in contact sports must be respected. SECOND ... a physician present at all contests and readily avail able during practice sessions. It is unfair to leave to a trainer or coach decisions as to whether an athlete should return to play or be removed from the game following injury. In serious injuries the availability of a physician may make the difference in preventing disability or even death ... (15:16). 10 As it has been pointed out, football because of the very nature of the game, accounts for a major proportion of athletic injuries. In a study made by the Carnegie Foundation for the Advancement of Teaching, twenty-two universities and colleges in different parts of the United States were investigated for incidents of athletic injuries. Among 44, 000 students, l , 3 2 0 serious accidents and injuries had occurred in one year. These included sprains, dislocations, concussions, fractures, collapses, and internal injuries. More than half of the l, 320 accidents were due to foot ball (lS:iii). Slocum and Larson reported a study of seventy-six patients per sonally examined and operated on whose injuries were located in the knee. An analysis of the results of the investigation showed that of the seventy six patients, sixty-five were athletic injuries. Forty of these occurred in football: twenty-five injuries resulted from lateral or posterolateral blows to the weight-bearing leg while running (clipping), nine occurred when the patient twisted a leg when suddenly changing direction while running, five injuries resulted from gang tackles, and one occurred when the patient received a lateral blow to the leg while standing (14:211-225). It appears significant to note the large number of football injuries with the variety of incidents resulting in injury. Larson and McMahan reported a study taking place with the school population of the area which includes the University of Oregon at Eugene. A study of l, 338 athletic injuries as viewed by a group of four orthopedists, 11 revealed 20 percent of such injuries to occur in the age group fourteen years old and younger and 40 percent in the group fifteen to eighteen years old. Sixty per cent of the students were in elementary and junior high schools, 15 percent in high schools, and 25 percent at the university. The high school students with 40 percent of the athletic injuries in the smallest numerical group appeared to be the most vulnerable to athletic injury. The authors concluded that the high incidence of joint injuries resulting from the high school students' participation in athletics was accounted for by many factors, including the nature of the athletic sport as well as the physical maturation of the player. The authors reflect upon the need for the coach to recognize these factors such as involving pre teenagers in a football game without limiting playing time, etc. They further pointed out that coaches consider the effects of possible injuries along with the benefits derived by youth participating in athletics (11 :607 612). The above studies point out the relevance of the game of football to the occurrence of athletic injuries, and the fact that principles for prevention and treatment of injuries should be acknowledged as a part of the educational philosophy of the coach and trainer. Trickett directs responsibility to the coach and asks him "What sort of man do you want [your child] to have as his coach?" He goes on to say: First of all, you want a man who knows his sport and can teach the skills required in that sport to those who come under his charge • • . . Certainly, you want a man who knows something 12 about the physiological and psychological make-up of the age group he is dealing with. What are their capabilities? What are their limitations? You want a man who can be inside the boy's head and see what makes him tick .•. (15:20). The author discusses the attitude of the coach and states that all too often youngsters are pushed too far too fast by coaches whose only philosophy~ seems to be to win at all cost, with apparent total disregard for the physical and emotional well-being of the youngsters: Although a great deal of the coach's responsibility for insuring the health and safety of the athlete is shared with his trainer and with the team physician, generally speaking it is the coach who must enforce the rules of conditioning, the rules of health, and the rules for safety that coach, trainer, and phy sician have set up (15:20-21). It is pertinent to reflect, at this point, upon the fact that while authorities are pointing out the need for coaches to assume knowledge and responsibility for the prevention of athletic injuries, there are many coaches whose attitudes about such occurrences of injuries are of a selfish nature. Trickett observes that there is no excuse for a coach not reporting an injury simply so the player can suit up and continue to be a member of the team. He says that time and again "I've heard of coaches saying, 'I'd rather have my star out there limping around than anybody I've got on my bench. 111 (15:23). Hirata is concerned with the lack of information available to the coach or injured player whenever such injuries happen to be reported. He '.stated the lack of professional knowledge by those in the medical field was also apparent when it came to the vast implications surrounding a 13 football knee injury, and similar athletic injuries: ..• For despite the many books and the voluminous literature by experts in the field, he will find, as I did, that the real problems, the difficulties that plague all doctors working directly in athletics, are either not to be found in the printed word, or are hidden in the middle of paragraphs dealing with more "major" clinical problems (8:3). Hirata further elaborated upon the lack of available medical data when he stated that "a frenzied scrutiny of the literature at the nearest medical library, or a quick look at one of the accepted classics will avail the doctor nothing" (8:3). This accusation by Dr. Hirata leads one to question why this is so. Why is there such a lack of accurate medical information on this level? Hirata gives an explanation: 11 serious11 The answer to these questions is simple. An overwhelming percentage of athletic disabilities are so minor as to warrant little or no attention from the devoted clinician, who deals only with conditions. A sore hamstring, asymptomatic except when a boy really "pours it on," is hardly worthy of notice; there is no real disability, the boy can continue to go to school, he is not in pain, so why worry about it? The serenes s will surely disappear if the part is adequately rested, will it not? Given sufficient time and rest, the complain cannot fail to disappear! (8:4) The long lasting results of knee injuries by some individuals attest to the fact that such lack of medical awareness and treatment is dis turbing. As Hirata emphasized, athletes and coaches fully and rightfully so, expect serious accidents and disabilities to be treated with efficiency, dispatch, and skill. But they also expect that any disability--no matter how minor--will be treated with the same efficiency, dispatch, and skill. 14 All disabilities are important and must be dealt with seriously and individually (8 :4-5). A comprehensive study of knee injury in sports has been recently reported by Klein and Allman. Their research is directed to the athletic team physician, athletic trainer, coach, and other physical education personnel. These authorities have clinics and treatment laboratories with which to develop methods to rapidly and completely restore the strength of muscles weakened by injury and disuse. Apparently, the importance of studying the knee injury problem is coming to the attention of professional educators (10). This was evidenced during the Second Annual Sports Medicine Seminar held in March at Seattle, Washington, when a major concern of medical and educational leaders present involved the problem of knee injuries. According to Bob Peterson, Head Trainer at the University of Washington, more coaches need to be aware of the definite causes of knee injuries. He said that many times the severity and longevity of the injury is brought about by the negligence or lack of knowledge by the person in charge--the coach. It was suggested that perhaps through a projected and mandatory program of interest, some of these problems could be eliminated by informing the coach as to how to diagnose and treat these injuries (12). In retrospect of the review of literature, it can be concluded that authorities in the fields of education and medicine acknowledge a lack of information on the part of both professions. While it was agreed that the 15 dangers and lasting implications of athletic injuries are apparent and of prime importance to the physical and mental well-being of the player, medicine and education need to join ranks and develop specific knowledge bases regarding the prevention and treatment of the problem. Chapter 3 DEFINITION I TREATMENT I AND REHABILITATION DEFINITION The knee injury is probably the most serious injury that occurs in football. Nowhere in athletic medicine are early examination and treatment more important. Certain results can be expected, but there is no miracle pertaining to knee injuries and their treatment. Let us examine some of the reasons or situations as to why an injury to the knee occurs. The knee is a very vulnerable joint and is not designed to accept undue stress or shear forces that might be placed upon it. The two biggest causes of injury are receiving a blow from the side such as delivered in a 11 side block 11 or being tackled and the undue stress that is present when cleats are firmly fixed in the turf. When these situa tions are presented and all factors involved, injury usually occurs. Some thing has to give and many times it is ligaments or cartilages found in the knee joint, especially those of high school boys whose joints and liga mentous structures are not entirely mature or fixed. The next phase to consider is how to evaluate the true extent of the knee injury. Complete and painstaking examinations must be undertaken 16 17 at the time of the injury and thereafter. Every advantage must be taken of X-ray and other diagnostic measures. Complete examination includes: First, an exacting history of the precise mechanism of injury, something that must be obtained immediately after the injury and before the athlete forgets exactly how it happened. Second, a thorough inspection of the entire knee joint for swelling or deformity must be made. Third, a sequential series of tests that must include a complete range of motion from hyperextension to full flexion, abduction and adduction in full extension as well as 15 degrees flexion, the "drawer" sign and rotation of the lower leg on the femur with the knee flexed to 20 degrees. No knee can be examined without each of these maneuvers nor can any injury be correctly evaluated by any single one without the others (8:214). Each maneuver has a specific meaning and the presence or absence of findings in each one of them is of lasting signifi cance. Fourth, all areas must be thoroughly palpated, checking for tenderness along the medial and lateral joint lines, the medial and lateral collateral ligaments, the medial femoral condyle, and finally, testing for true joint effusion as contrasted to prepatellar effusion while routinely pressuring the fat pad area for suggestive thickening or tenderness. Only after this complete examination can a working diagnosis be formulated and a program of future rehabilitation be established. 18 Contusions The next step shall be to consider the types of knee injuries encountered, the first of which will be contusions. There are many types of contusions which are the result of a specific incident of impact. These are almost always possible to determine within the first minutes of evalua tion. If the blow was neither sufficiently forceful nor remarkable to cause any counter-joint motion, the player will be able to state this with a positive knowledge that can be depended upon. The site must then be carefully located and inspected, keeping in mind possible confusion with contusions on the femoral condyle and associated neighborhood symptoms that might falsely suggest collateral ligament strain. Also, the "low char lie" with its penchant for supra patellar bursa! bleeding must be kept in mind. Also, bruises of the bony surfaces of the condyles or of the patella itself can occur with local characteristics typical of the bone bruise. Minor Ligament Strains The second type of injury to be discussed will be the minor ligament strains. Minor ligament strains are evidenced first by a history of counter joint force; and second, by distinctly localizeable tenderness along the length of the medial or lateral collateral ligaments. Occasionally this tenderness is limited to a narrow area, but this is diagnostic even in the absences of demonstrable instability either in full extension or at 15 degrees flexion. The most common type of ligament strain is characterized by some 19 degree of demonstrable laxity in the involved ligament with a distinct elas ticity on abduction or adduction at 15 degrees flexion; and in a few days is as tight and stable as ever. Two other types are the medial collateral strain and the lateral collateral strain which are not serious injuries as long as there is full range of motion and full hyperextension in the standing position. Ligament Tear The next injury type that will be discussed is the complete or near complete collateral ligament tear. All the symptoms present in ligament strains are present, but to a greater degree. Abduction or adduction is greatly evidenced without any sense of elasticity at all and full quadriceps stabilization in extension does not alter the degree of lateral instability. In cases of complete collateral tear, the only remaining stability is provided by the medial joint capsule itself. If this is partially torn, there may be so little support that the true limits of lateral angulation of tibia or femur can be downright frightening. If there is joint-line tenderness and limitation of extension or hyperextension by more than five degrees, a cartilage injury must be suspected which is the next injury type to be discussed. Every opportunity should be afforded the knee to spontaneously resolve under these circum stances since past experiences has shown that a large proportion of these subside spontaneously, full range of motion returns, joint-line tenderness 20 disappears, and the football player can return to full participation. Close observations should be maintained on the knee because re-injury or lack of proper attention and care will undoubtedly result in surgery to remove the damaged cartilage. Anterior Cruciate Integrity Now we come to the "drawer sign" and its true meaning, the presence or absence of anterior cruciate integrityo(8:214). This is directly dependent upon an immediate on-the-spot examination which may be the most revealing before any reflex spasms of the hamstrings can develop to completely obscure any possible positive sign. Of additional importance in all knee injuries, but particularly in cases of ligament strain, is the rapidity of quadriceps atrophy. This atrophy is sometimes evident within three or four days and is apparent in the lower-most portion of the bastus medialis, just above the patella. This atrophy is all the more evident because of the usually extraordinary development of this muscle group in the football player or any other com petitive athlete. Ironically, this is usually the last segment of the quadriceps to develop even after the most strenuous competition over many years and is the first to go after injury. It must be restored as soon as possible to stabilize the injured knee. 21 The Retropatellar Fat-Pad Another injury that occurs to the knee is the retropatellar fat-pad to use medical terminology, but is commonly called the "pinched fat-pad" in athletic terms. This injury is characterized by the complain of pain in the kneecap or patella area on hyperextension. A thorough examination may fail to reveal any ligamentous instability, joint-line tenderness, or evidence of internal damage; yet the football player will still complain of pain and increasing discomfort directly behind the patella. Examination of this area reveals an ill-defined soft tissue thickening on both sides of the patella, which is exceedingly tender and is most often termed as a bruise. Under normal circumstances this injury might not be too noticeable and would present only minor discomfort. However, under the stress of compe titive athletics such as in football, the incessant demand on repetitive knee action is certain to pinch the pad sooner or later. Once this pinching occurs, hemorrhaging results and the pinched or damaged tissues swell more and present a larger protruding mass that is painful and tender. During this time the symptoms and the discomfort increase unless activity is pro hibited until this "fat-pad" and the surrounding tissue have had the oppor tunity to return to normal or ordinary corrditfon. Prepatellar Bursitis Prepatellar bursitis is another knee injury that is of concern to football players. Commonly labeled as "water on the knee, " it is 22 characterized by excessive fluid present on the knee, usually caused by a blow or impact to the bursa. This condition is usually eliminated by aspir ation, ice, and compression or use of steroids. Also of great importance is the use of a greater amount of padding or a more absorbent type knee pad to insure adequate protection and prevent further aggrevation or damage to the irritated bursae. There are other injuries .or problems to the knees such as Osgood Schlatter' s Disease and Menisectomy, but since these are not usually an injury caused directly by football, they will not be discussed at this time. Many times they may create difficulties for the football players vJ1 ich are then labeled as injuries caused by football. Also there are the rare but easily recognized dislocation of the patella. This injury is usually lateral and is very painful and disabling. The deformity of a knee whose patella has been displaced laterally out of the condyle notch and is locked into a lateral position is impossible to miss. Immediate replacement by a qualified person such as a physician or team trainer should take place on the spot of the injury before spasms and swelling occur. Any delay in replacement of the patella causes increased pain and difficulty. Immediate attention should follow in the form of X-rays for possible bone chips or fractures and to determine if surgery is necessary for complete treatment and correction of the injury. 23 TREATMENT The next phase to be considered is the treatment and rehabilitation of the knee. First of all, when a knee injury occurs, any good coach, trainer, or doctor should practice a sound "on-the-field" routine. This means that the injured player should be supported or carried from the field either by his teammates or on a stretcher. This is no time for heroic efforts or "tough it out" attempts which will bring the oh's and ah's from the fans and possible increased injury to the player. The fans will clap and the cheerleaders will give him fifteen rahs regardless of how he leaves the field, so think of the injured knee and carry him off the field. The injured knee should be packed in ice immediately and elevated. Hopefully, a team physician or trainer will examine the knee before a great amount of swelling occurs. A compression pad of cotton batting or composition roll is placed over the knee and wrapped with an elastic bandage. Nowhere in athletic medicine are early examination and early treatment more important. It is difficult to examine an injured knee adequately three or four hours after the time of injury. Swelling and muscle spasms occur and make functional tests for stability and flexion unreliable and difficult to perform. Early diagnosis and treatment usually enhance the speed of recovery and most of the time insure more positive results. Knowing how the injury occurred is extremely important in evaluation of the nature and extent of the injury. One of the most important factors is that all knee injuries require immobilization until 24 the exact nature of the injury is determined. If the football player is allowed to walk on an injured knee, changes or increased damage might occur which might mean that the joint cannot be repaired properly even through surgery. In the case of minor knee injury such as partial or minor ligament tears and strains, the boy should be required to use crutches probably for a minimum of three or four days or longer depending on a doctor's prescribed treatment. This is to keep all weight off the knee to prevent aggravating the injury and to allow the swelling to decrease. Many times a cast is required to insure immobilization of the knee joint. The majority of the knee injuries will involve the medial meniscus which is the medical term for the cartilaginous surface of the joint (3:114). Injuries of this type require surgical repair, usually the sooner, the better the outcome of the injured knee. Although a boy may continue to play with cartilage damage, his knee will begin to lock, causing increasing pain, greater damage, and decreasing palying efficiency, which is why surgery is so necessary. In the cases of complete ligament tear, surgery is required to insure proper results in re-establishing the knee. Frequently both the collateral and cruciate ligaments are torn. It is possible for a person in normal life to function with torn cruciates, but not a football player who is subjecting his knee to abnormal stresses. 25 One of the biggest problems that complicate the diagnosis of the knee injury is the almost uselessness of the X-ray. Any broken bone, bone chips, dislocated patella, or similar injury will show up on the X-ray, but not a damaged cartilage or ligament. Therefore, it is imperative that a physician or trainer examine and diagnose the injury or refer the injured player to an orthopedic specialist. Also of equal importance is to be aware of any previous injury that might have been sustained by the knee. The biggest therapeutic improvement in the treating of soft tissue injuries is the use of medications known as enzymes, such as Papase Ananase or similar proteolytic type. These enzymes will reduce the injury and discoloration period by apparently speeding the re-absorption of blood and fluid in the injured area (11 :87). Also, they have a tremendous psychological effect on the injured player because they are fairly new and not too well known by the average person. Another phase in the treatment of the knee is to start whirlpool therapy approximately 48 hours after cessation of treatment with ice. This should be done gradually and is definitely not to be used for a minimum time -period of 48 to 72 hours after the time the injury was sustained. Heat therapy through the use of the whirlpool bath should begin at fairly low or moderate temperatures and gradually increased to a higher degree. However, it is necessary to consult with the physician who is treating the injury since only those of a minor nature will respond while those of a more serious nature will probably require surgery. 26 REHABILITATION Most of the time football players are great patients physiologi cally and psychologically. They are fine physical specimens and usually have been ingrained to accept and live with injury and pain. However, too many times these same players are subjected to unrealistic rehabilitation, probably because of their playing ability, with too little regard for their physical being and the nature of their injury. Hopefully, these situations may be avoided by leaving the boy under the care of the attending physician and thus making him responsible for instituting and supervising the rehabili tation processes. Before a boy is returned to the football field, his knee should be at least as strong as it was before the injury. The main problem that a boy is faced with is atrophy of the muscles supporting the knee, particularly the quadriceps group:. Because the strength and stability of the knee is dependent upon the quadriceps, it is important that this muscle group is at least at its original strength to provide these qualifications. Basically, there is not much reason why extensive atrophy should occur; but it often does, usually because of negligence and unawareness. Even on the day of the injury, work can begin with the quadriceps muscles. When the leg is fully extended, the boy can contract the muscles and hold it for approximately five seconds. No joint movement is involved and a boy should be able to do two or three sets of ten repetitions of this post 27 operative exercise. This is nothing more than a simple isometric exercise and will aid in good muscle tone which is easier to maintain than to rebuild after the muscles have been allowed to atrophy. As soon as the boy's condition permits, he should begin raising the leg in a fully extended position to strengthen the quadriceps. If his leg is in a cast, he can use isometric type exercises by having someone hold the cast whi_le he exerts force upward. The hamstring muscles group can be strengthened in the same manner by simply having the boy roll over on his stomach and force up on the leg against the cast or stay on his back or in a sitting position and exert downward pressure. As soon as possible, attempts to restore full flexion to the knee should be made. The type of injury will determine what treatment and what type of motion should be used. Probably the best exercise to begin with is to have the boy sit on the edge of a table with the lower portion of his leg hanging down over the side and flex the knee. The weight of the leg itself will be enough at the beginning. He should raise the leg until it is straight and then slowly lower it to the original starting position. A boy should start out with five to eight repetitions and gradually increase according to the individual 1 s tolerance and endurance. As soon as the boy has achieved a reasonable range of motion, he should begin to walk. Here is where the team trainer or physician should be consulted. Emphasize the point of not limping or favoring the knee. This will be difficult in the beginning, but it is important when striving to 28 rebuild strength and endurance. After a reasonable length of time, he should begin running to establish stability to the knee. As progress is made, the boy should do a few simple agility drills such as quick starts and stops, cuts, figure eights, and other similar maneuvers. This should be a gradual process determined by the type and nature of the injury and designed to restore the knee to full use. Many types and variations of exercises are used to rehabilitate the knee. Some of them are running and bicycle riding, preferably on a stationary or exercise type mode so that the injured player can be properly supervised. Another exercise to be utilized after flexion is to use weights such as the boot, sandbags, or the quadriceps bench, such as is designed in the Universal Gym Set or the Marcy Gym Set. There are many home-made apparatus such as inner tubes, springs, etc., that can be manufactured to fit the individual budget and facilities and provide adequate exercise. Over-exercising can be as dangerous as under-exercising, but is not so common. Therefore, supervision and guidance are essential so that any attempted exercise is not extended beyond tolerance and results in retarding rehabilitation. The boy must be encouraged to do enough exercise to insure his opportunity to return to the football field. Again, it should be emphasized that a knee strong enough to allow a boy to bowl, dance, and lead a normal everyday life may not be strong enough to withstand the stresses and strains that it will be subjected to in football. 29 Once the player returns to football practice, the injured knee is still of primary concern. How do you support the knee? Externally, the most elaborate devices of steel, plastic, rubber, canvas, and elastic have failed to provide adequate support under the daily demands of football. Granted there are some such as the Palmer knee brace that seem to do a better job than others, but~ are really satisfactory. Ta ping the knee every day seems to provide the best results, but this proves to be costly to some athletic budgets and is not always 100 percent effective. The. main concern should be for the stability of the knee in order to allow the player to participate without excess danger of re-injury. Any boy whose knee is so unstable that it cannot withstand the demands of football which occur when flexed should be prevented from participation regardless of his own desire, parental pressure, or his "importance" to the team. No boy should be subjected to possible permanent injury to win a game or cham pionship. These cases are usually the exceptions rather than the usual cases, but this should be kept in mind. The next item: to look at is the role of football cleats in knee injuries. In the past few years, there has been a great deal of concern, study, and experimenting in the correlation of the knee injury and the football cleats. Hirata reports that originating with Hanley at Bowdoin, who demonstrated a convincing relationship between cleats which were firmly fixed in the ground and subsequent knee injury, there has been many modifications and changes (8:229). The cleats have been shortened, 30 rounded, made into circular discs and flat bars, redesigned like soccer cleats, made from rubber, metal, and plastic, but still knee injuries occur. In some cases, the heel cleats have been replaced by an ordinary shoe heel in an attempt to prevent injury. Knee injuries can and do occur if the heel becomes firmly locked in the ground, thereby creating torsonial forces to the knee (8:235). This is compounded when impact is added, such as a block or tackle, especially from the side. This leaves a great deal of speculation and second guessing to all concerned parties and provides a great selling point to the manufacturers of football shoes. Chapter 4 SUMMARY AND RECOMMENDATIONS Throughout the paper, the writer has endeavored to objectively and thoroughly examine some of the various types of knee injuries that occur in football. A review of related literature showed that while medical and educational authorities were aware of the problem, a definite lack of literature in both areas often leads to haphazard treatment and attitudes by doctors and coaches alike • The main points that were emphasized in the paper were those factors relating to methods of treatment and rehabilitation of the knee. It appears that the most successful cases of knee injuries and their recovery are determined by intelligent and early diagnosis and treatment. It is the tendency of too many of us in coaching to be more concerned with the "toughness" of the player and his immediate return to action on the playing field. With football players, it is especially important to diagnose the injury immediately, treat it, and personally supervise the post-operative care and muscle development. It is not always possible for the average coach to be an outstanding authority on every injury, but it, is possible to apply common sense, concern for the injured player, and some basic knowledge of how to care for athletic injuries. 31 32 Our main concern must be a return to 100 per cent normal func tioning of the player's knee. How this goal is achieved depends upon the coach, his concern and interest, the cooperation and rapport established with a qualified physician, and how each individual case is handled. Bearing in mind the statement from Coach Duffy Daugherty of Michigan State University, "Dancing is a contact sport, football is a collision sport," each one of us is responsible to be aware of the symptoms of a knee injury and the steps to follow to achieve the best possible results. It is recommended that educators, and especially the athletic coach, take a sincere look at his school's policies and procedures regarding the prevention and treatment of injuries occurring on the football field. A baseline knowledge for guidance in the area of injury prevention is a necessary prerequisite to any educational endeavor when one is responsible for the safety of young people. This responsibility is of direct concern to the athletic coach whose influence on the mental and physical well-being of the athlete is powerful. Administrators should allow time for coaches to participate in professional training courses directed toward the safety and health of the student participants. Finally, it is recommended further investigations be made relating to the prevention and treatment of all injuries which might occur during school athletics. The provision of proper and immediate medical attention to the athlete which enables him to continue to participate in a sport he loves and which 33 will prevent him from being forced to live for the rest of his life with a disability that could have been prevented, should be the desire of every athletic coach. BIBLIOGRAPHY 34 BIBLIOGRAPHY 1. Cullen, Charles C. Orthopedic and Surgical Appliances, 8th and Olive Way, Seattle, Washington. 2. Daniels, Arthur S. and Evelyn A. Davies. Adapted Physical Education. New York: Harper & Row, Publishers, 19 65. 3. Dayton, William. Athletic Training and Conditioning. New York: Ronald Press Company, 1960. 4. De Palma, Anthony F. Clinical Orthopaedics. Philadelphia and Montreal: J. B. Lippincott Company, 19 6 2 • 5. • The Management of Fractures and Dislocations. Philadelphia and London: W. B. Saunders Company, 1964. 6. Grant, J. C. An Atlas of Anatomy. Baltimore: The Williams and Wilkins Company, 19 61. 7. Gray, Carolyn E. Textbook of Anatomy and Physiology. New York: The Macmillan Company, 19 63. 8. Hirata, Isao, Jr., M. D. The Doctor and the Athlete. Philadelphia: J. B. Lippincott Company, 19 68. 9. Kerr, Barry A. "Knee Extension Movement," Research Quarterly, Vol. 37, No. 2, May, 1966. 10. Klein, Karl K. The Knee in Sports. New York: The Pemberton Press, Jenkins Publishing Company, 19 69. 11. Larson, Robert L. , M. D. , and Robert 0. Mc Mahan, M. D. "The Epphyses and the Childhood Athlete," The Journal of the American Medical Association, 196:607-612, May 16, 1966. 12. Second Annual Sports Medical Seminar, Seattle, Washington, March, 1969. 13. Slocum, Donald B. , M. D. "The Mechanics of Common Football Injuries," The Journal of the American Medical Association, 170:1640-1646, August 1, 1959. 36 14. Slocum, Donald B., M. D., and Robert L. Larson, M.D. "Rotatary Instability of the Knee," The Journal of Bone and Joint Surgery, 50-1 :211-225, March, 19 68. 15. Spalteholz, Werner, M. D. Hand Atlas of Anatomy. Philadelphia: J.B. Lippincott Company, 1959. 16 • Thorndike, Augustus. Athletic Injuries, Prevention, Diagnosis, and Treatment. Philadelphia: Lea & Febiger, 1948. 17. Trickett, Paule., M. D. Athletic Injuries. NewYork: Appleton Century-Crofts, 19 65. 18. Wakefield, Charles T. , M. D. , Port Orchard Medical Clinic, Port Orchard, Washington. APPENDIX T. •UCKNEA, M.D. (1959) E. MCCONVILLE, M.D. I. CALLAHAN, M.D. J. ELLll:NGE•, M .D. Please note: Signature has been removed due to security concerns EA•T 9-D~DD ORS. MCCONVILLE, CALLAHAN & ELLINGER 701 SIXTEENTH AVENUE SEATTLE, WA19HINlllTCN 99122 Mey 19, 1969 Mr. IBrry Maguire Footbal 1 Coach South Kitsap High School Port Orchard, Washington, 98366 Dear Mr. Maguire : l(y" most sincere apology for the delay in answering your letter. In going over your letter I would suggest that you get hold af a copy ar ''Treatment af Injuries to .Athletes" by Dr. Don O'Donoghue. This book wes first published in 1962 by the W. B. Saunders & Canpeny af Philadelphia end actually is ''The Bible" for doctors who treat injured athletes. I em sure that any doctor friend af yours in the canmunity would have this or make it available to you through e county medical library. At the .Athletic Injury Conference in Oklahane City this year one of the better days was spent on a break dawn on the knee in its relationship to athletic injuries. This included the extensor mechanism, the knee ligaments which wes subdivided into the medial canpirtment, lateral canpartment, end posterior canpartment, es wEi 1 es the cruciete ligaments. A separate day was likewise spent on cartilage injuries. I would think that if you could break down your thesis along these lines you might have a very workable plan • .Another end sanewbat newer book ''The Doctor end the Athlete" by Isao H:lreta, Jr. has recently been published by the J. B. Lippincott Canpaey. This takes up injuries more or less in en enatanicel division. rather than by sports. There h • great deal ar good inf o:rmation in this book end it is readily available to anyone through any reliable book store. If I can be of any fl.Il"ther help to you, kindly call. With kind personal regards,

Master of Education Master of Education by Larry W. Maguire August, 1969 UOllJU!l{llli M '11.mqlU9(f3 ~}1~no3 atVJS ao~!'l98M 194-0 A.J•.aqn APPROVED FOR THE GRADUATE FACULTY ________________________________ Everett A. Irish, COMMITTEE CHAIRMAN _________________________________ Stanley A. Sorenson _________________________________ Dohn Miller ACKNOWLEDGEMENT The writer wishes to extend his gratitude to Dr. Everett Irish for his advice and for serving as Chairman of the Graduate Committee. Appre ciation is also expressed to Dr. Dohn Miller and Mr. Stanley Sorenson for their aid and for serving on the Graduate Committee. I am most grateful to my family for their encouragement and patience. TABLE OF CONTENTS Chapter 1. 2. 3. THE PROBLEM AND DEFINITION OF TERMS • THE PROBLEM • Statement of the Problem Importance of the Study • Limitations of the Study • Overview of the Pa per DEFINITION OF TERMS REVIEW OF LITERATURE • DEFINITION, TREATMENT, AND REHABILITATION • DEFINITION Contusions • Minor Ligament Strains • Ligament Tear • Anterior Cruciate Integrity • The Retropatellar Fat-Pad Prepatellar Bursitis TREATMENT • REHABILITATION Page 1 2 2 3 3 4 5 7 16 16 18 18 19 20 21 21 23 26 4. SUMMARY AND RECOMMENDATIONS • 31 v Chapter BIBLIOGRAPHY APPENDIX • Page 34 37 Chapter 1 THE PROBLEM AND DEFINITION OF TERMS Knee injuries are probably the most common of all athletic injuries. They are almost as common in football as ankle injuries and are far more disabling. Coaches and teachers in the field of physical education and particularly athletics are indirectly responsible for the safety of their student participants in the program they are conducting. Therefore , it is imperative that educators be aware of the implications surrounding such injuries. Today, man enjoys football and other athletic events both as recreation and as competitive sports. Since the year 1933, when the first pamphlet on the prevention and care of athletic injuries was written, there has been a great many medical discoveries and advances which have increased the knowledge as to how to diagnose, treat, and rehabilitate an injury to the knee. Unfortunately, however, those educators working directly in the area of athletics, are not always aware of the implications and events leading to the possibility of injuries which occur to the athlete. In any case, the effects of the injuries are not always recognized as being factors to take into consideration when planning and implementing the athletic program. While the knee injury to the star athlete is widely 1 2 reported by the news media, and the "football knee" is so widely recog nized, no coach or instructor can be expected to be an expert in the surgical treatment of such injuries. There is, however, a need for the coach and instructor to be familiar with the problems surrounding the injury in order that precaution can be taken, and activities eliminated which pro vide for the safety of the student participant. THE PROBLEM Statement of the Problem Coaches entering the area of football need to be aware of the factors involved in knee injuries. Both experienced and inexperienced coaches can benefit from research which will enable him to adequately care for any injuries which may arise. Often coaches in athletics do not have available to them, ready information covering this problem. There fore, the purpose of this investigation was to provide relevant data per taining to all facets of the knee injury as it occurs in football; the diagnosis of the injury; prescribed treatment; qnd the actual rehabilitation of the knee. Attention will be given to these areas in hopes that the problems accom panying such an injury may be thoroughly examined and reached a better understanding. 3 Importance of the Study The value of competitive sports, especially the contact sports, is inevitably a part of our culture and is exhibited in everyday life. Injuries occur; therefore, the more knowledge that can be obtained, the better the care that can be given. In the contents that follow, this infor mation will be presented and evaluated in an effort to attain a more thorough understanding of one small phase within the scope of athletic injuries. An overall examination of the knee injury as it occurs in football and the treatment involved will be of significance to those coaches who realize the importance and the personal responsibility for being cognizant of these problems with their players. The writer developed this comprehensive overview of the knee injury problem with the intent of providing a framework of knowledge for himself as well as to other coaches and administrators who may benefit from such material for personal use. Such available data gleaned from the research of medical and educational authorities will be of value to the coach or administrator who does not have the time or facilities to pursue such an investigation. Limitations of the Study There was no attempt to compare or evaluate training or other coaching methodologies relating to the incidents of knee injuries. This research investigation was undertaken only to provide a comprehensive 4 compilation of data which could serve as a resource guide. It was not the purpose of this study to formulate conclusions based on statistical analysis of the significance or la sting effects of the knee injury. It was determined that a knowledge base regarding the care and prevention was a more worthwhile approach to the problem, rather than a mere review of cases of knee injuries taking place during the athletic sport of football. A further limitation to the study was the lack of literature provid ing a comprehensive overview of all facets of the knee injury problem. Literature on the subject was emersed in various fields of discipline as is shown in the Bibliography of this paper. Overview of the Paper Chapter 2 presents the opinions of authorities in the fields of medicine and education regarding the significance of the knee injury problem and how such injuries affect the physical and mental well-being of the injured person. The review of literature pertaining to athletic injuries was attempted in an effort to gain insight into this area of concern and also to provide rationale for the compilation of a comprehensive guide on foot ball knee injuries for use by the coach and athletic administrator. Chapter 3 is the presentation of the resource material which delineates various factors concerned in the specific knee injuries pertinent to the football player. This research data provides a basic guide for use by the coach and administrator. 5 Chapter 4 summarizes the research investigation and offers recommendations for further research. DEFINITION OF TERMS Cause of Injury Definite origin of why damage was inflicted to a part of the body. Contusions Type of bruising injury in which no tearing or breaking of the skin occurs. Rehabilitation To restore to the original state. Drawer Sign The presence of abnormal forward movement of the knee joint. Anterior Cruciate Integrity Proper functioning of knee joint through normal movements. Retropatellar Fat-Pad A pained area directly behind the knee cap due to hyperextension or a blow to this area. 6 Knee Injury Damage to the lower extremity of the leg caused by a blow, striking force, or other similar pressure. Prepatellar Bursitis Technical term for "water on the knee," which is an excess amount of fluid accumulated around an injured area. Chapter 2 REVIEW OF LITERATURE A major concern of most coaches and parents of players is the possible incidence of injury to the participant in the athletic event. Authorities in the area of physical education point to the need for coaches and other teaching personnel to cooperate with the family and community in preventing the occurrence of injury on the playing field, and providing for optimum programs in sports and athletics: ... new and imposing demands will be made on teachers and administrators. More effective coordination with medical personnel, the home, and public, semipublic, and private agencies will have to be developed • . . (2 :xi-xii) . Hirata (18:210) remarks upon the inability of the coach to assume the task of being an expert in the surgical treatment of knee injuries, or an expert in the reconstruction of permanently damaged knees. He also explains the necessity for educators to elicit the assistance of those in the medical profession and the need for schools to provide competent doctors "primarily responsible for the health of athletes in a controlled program." According to Daniels and Davies, teachers and coaches: . need to know a great deal about the structure and function of the human organism. They must understand not only normal structure and function, but also the effects of disease and injury, 7 8 and the kinds of experiences ... to remove the condition, or at least minimize its effect on total living (2:81). While the employment of a medical specialist is often beyond the financial realm of many school districts, it is conceivable to expect those educators involved in the athletic program to avail themselves of any resource person or research data which will guide them in the direction of prevention and safety. Dr. Donald B. Slocum points to the need for the coach to become aware of the manner in which injury may be incurred and the injuries most likely to occur in a given situation. He said that football presents "certain inescapable injury hazards, due to the very nature of this vigorous body contact sport" and that a knowledge of the mechanics of these injuries is vital if adequate medical history and effective diagnosis is to be made. He further states: Classifying the injuries incurred by football players has given valuable clues for prevention, diagnosis, and treatment .... Here probably the most lethal weapon in football is the oncoming knee, which exerts forces that must either be absorbed by the head or transmitted to the vertebral column (13:1640). Another member of the medical profession, Dr. Paul Trickett, Director of Athletic Medicine at Tulane University, remarks upon the psycho logical effects of the football injury. He states that while physically the injured player may recover, the trauma factor is always present and indeed increasing with the "intensity of participation" in the athletic event" (lS:iii). Therefore, it would seem that the coach and athletic trainer must 9 recognize the possible traumatic psychological effects of injuries as well as the physical implications. Trickett lists "The Bill of Rights for the College Athlete" and a review of his statements leads the reader to the realization that such a "Bill of Rights" is applicable to any coach or player from the elementary school level and higher: Participation in college athletics is a privilege involving both responsibilities and rights. The athlete has the responsibility to play fair, to give his best, to keep in training, to conduct himself with credit to his sport and his school. In turn he has the right to optimal protection against injury as this may be assured through good technical instruction, proper regulation and conditions of play, and adequate health supervision. GOOD COACHING: The importance of good coaching in protect ing the health and safety of athletes cannot be minimized. Technical instruction leading to skillful performance is a significant factor in lowering the incidence and decreasing the severity of injuries. Also, good coaching includes the discouragement of tactics, outside either the rules or the spirit of the rules, which may increase the hazard and thus the incidence of injuries. GOOD EQUIPMENT AND FACILITIES: There can be no question about the protection afforded by proper equipment and right facilities. Good equipment is now available and is being improved continually; the problem lies in the false economy of using cheap, worn-out, outmoded, or ill-fitting gear. Provision of proper areas for play and their careful maintenance are equally important. GOOD MEDICAL CARE . . . Including: FIRST •.. a thorough preseason history and physical examination. Many of the sports tragedies which occur each year are due to unrecognized health problems. Medical contraindications to partici pation in contact sports must be respected. SECOND ... a physician present at all contests and readily avail able during practice sessions. It is unfair to leave to a trainer or coach decisions as to whether an athlete should return to play or be removed from the game following injury. In serious injuries the availability of a physician may make the difference in preventing disability or even death ... (15:16). 10 As it has been pointed out, football because of the very nature of the game, accounts for a major proportion of athletic injuries. In a study made by the Carnegie Foundation for the Advancement of Teaching, twenty-two universities and colleges in different parts of the United States were investigated for incidents of athletic injuries. Among 44, 000 students, l , 3 2 0 serious accidents and injuries had occurred in one year. These included sprains, dislocations, concussions, fractures, collapses, and internal injuries. More than half of the l, 320 accidents were due to foot ball (lS:iii). Slocum and Larson reported a study of seventy-six patients per sonally examined and operated on whose injuries were located in the knee. An analysis of the results of the investigation showed that of the seventy six patients, sixty-five were athletic injuries. Forty of these occurred in football: twenty-five injuries resulted from lateral or posterolateral blows to the weight-bearing leg while running (clipping), nine occurred when the patient twisted a leg when suddenly changing direction while running, five injuries resulted from gang tackles, and one occurred when the patient received a lateral blow to the leg while standing (14:211-225). It appears significant to note the large number of football injuries with the variety of incidents resulting in injury. Larson and McMahan reported a study taking place with the school population of the area which includes the University of Oregon at Eugene. A study of l, 338 athletic injuries as viewed by a group of four orthopedists, 11 revealed 20 percent of such injuries to occur in the age group fourteen years old and younger and 40 percent in the group fifteen to eighteen years old. Sixty per cent of the students were in elementary and junior high schools, 15 percent in high schools, and 25 percent at the university. The high school students with 40 percent of the athletic injuries in the smallest numerical group appeared to be the most vulnerable to athletic injury. The authors concluded that the high incidence of joint injuries resulting from the high school students' participation in athletics was accounted for by many factors, including the nature of the athletic sport as well as the physical maturation of the player. The authors reflect upon the need for the coach to recognize these factors such as involving pre teenagers in a football game without limiting playing time, etc. They further pointed out that coaches consider the effects of possible injuries along with the benefits derived by youth participating in athletics (11 :607 612). The above studies point out the relevance of the game of football to the occurrence of athletic injuries, and the fact that principles for prevention and treatment of injuries should be acknowledged as a part of the educational philosophy of the coach and trainer. Trickett directs responsibility to the coach and asks him "What sort of man do you want [your child] to have as his coach?" He goes on to say: First of all, you want a man who knows his sport and can teach the skills required in that sport to those who come under his charge • • . . Certainly, you want a man who knows something 12 about the physiological and psychological make-up of the age group he is dealing with. What are their capabilities? What are their limitations? You want a man who can be inside the boy's head and see what makes him tick .•. (15:20). The author discusses the attitude of the coach and states that all too often youngsters are pushed too far too fast by coaches whose only philosophy~ seems to be to win at all cost, with apparent total disregard for the physical and emotional well-being of the youngsters: Although a great deal of the coach's responsibility for insuring the health and safety of the athlete is shared with his trainer and with the team physician, generally speaking it is the coach who must enforce the rules of conditioning, the rules of health, and the rules for safety that coach, trainer, and phy sician have set up (15:20-21). It is pertinent to reflect, at this point, upon the fact that while authorities are pointing out the need for coaches to assume knowledge and responsibility for the prevention of athletic injuries, there are many coaches whose attitudes about such occurrences of injuries are of a selfish nature. Trickett observes that there is no excuse for a coach not reporting an injury simply so the player can suit up and continue to be a member of the team. He says that time and again "I've heard of coaches saying, 'I'd rather have my star out there limping around than anybody I've got on my bench. 111 (15:23). Hirata is concerned with the lack of information available to the coach or injured player whenever such injuries happen to be reported. He '.stated the lack of professional knowledge by those in the medical field was also apparent when it came to the vast implications surrounding a 13 football knee injury, and similar athletic injuries: ..• For despite the many books and the voluminous literature by experts in the field, he will find, as I did, that the real problems, the difficulties that plague all doctors working directly in athletics, are either not to be found in the printed word, or are hidden in the middle of paragraphs dealing with more "major" clinical problems (8:3). Hirata further elaborated upon the lack of available medical data when he stated that "a frenzied scrutiny of the literature at the nearest medical library, or a quick look at one of the accepted classics will avail the doctor nothing" (8:3). This accusation by Dr. Hirata leads one to question why this is so. Why is there such a lack of accurate medical information on this level? Hirata gives an explanation: 11 serious11 The answer to these questions is simple. An overwhelming percentage of athletic disabilities are so minor as to warrant little or no attention from the devoted clinician, who deals only with conditions. A sore hamstring, asymptomatic except when a boy really "pours it on," is hardly worthy of notice; there is no real disability, the boy can continue to go to school, he is not in pain, so why worry about it? The serenes s will surely disappear if the part is adequately rested, will it not? Given sufficient time and rest, the complain cannot fail to disappear! (8:4) The long lasting results of knee injuries by some individuals attest to the fact that such lack of medical awareness and treatment is dis turbing. As Hirata emphasized, athletes and coaches fully and rightfully so, expect serious accidents and disabilities to be treated with efficiency, dispatch, and skill. But they also expect that any disability--no matter how minor--will be treated with the same efficiency, dispatch, and skill. 14 All disabilities are important and must be dealt with seriously and individually (8 :4-5). A comprehensive study of knee injury in sports has been recently reported by Klein and Allman. Their research is directed to the athletic team physician, athletic trainer, coach, and other physical education personnel. These authorities have clinics and treatment laboratories with which to develop methods to rapidly and completely restore the strength of muscles weakened by injury and disuse. Apparently, the importance of studying the knee injury problem is coming to the attention of professional educators (10). This was evidenced during the Second Annual Sports Medicine Seminar held in March at Seattle, Washington, when a major concern of medical and educational leaders present involved the problem of knee injuries. According to Bob Peterson, Head Trainer at the University of Washington, more coaches need to be aware of the definite causes of knee injuries. He said that many times the severity and longevity of the injury is brought about by the negligence or lack of knowledge by the person in charge--the coach. It was suggested that perhaps through a projected and mandatory program of interest, some of these problems could be eliminated by informing the coach as to how to diagnose and treat these injuries (12). In retrospect of the review of literature, it can be concluded that authorities in the fields of education and medicine acknowledge a lack of information on the part of both professions. While it was agreed that the 15 dangers and lasting implications of athletic injuries are apparent and of prime importance to the physical and mental well-being of the player, medicine and education need to join ranks and develop specific knowledge bases regarding the prevention and treatment of the problem. Chapter 3 DEFINITION I TREATMENT I AND REHABILITATION DEFINITION The knee injury is probably the most serious injury that occurs in football. Nowhere in athletic medicine are early examination and treatment more important. Certain results can be expected, but there is no miracle pertaining to knee injuries and their treatment. Let us examine some of the reasons or situations as to why an injury to the knee occurs. The knee is a very vulnerable joint and is not designed to accept undue stress or shear forces that might be placed upon it. The two biggest causes of injury are receiving a blow from the side such as delivered in a 11 side block 11 or being tackled and the undue stress that is present when cleats are firmly fixed in the turf. When these situa tions are presented and all factors involved, injury usually occurs. Some thing has to give and many times it is ligaments or cartilages found in the knee joint, especially those of high school boys whose joints and liga mentous structures are not entirely mature or fixed. The next phase to consider is how to evaluate the true extent of the knee injury. Complete and painstaking examinations must be undertaken 16 17 at the time of the injury and thereafter. Every advantage must be taken of X-ray and other diagnostic measures. Complete examination includes: First, an exacting history of the precise mechanism of injury, something that must be obtained immediately after the injury and before the athlete forgets exactly how it happened. Second, a thorough inspection of the entire knee joint for swelling or deformity must be made. Third, a sequential series of tests that must include a complete range of motion from hyperextension to full flexion, abduction and adduction in full extension as well as 15 degrees flexion, the "drawer" sign and rotation of the lower leg on the femur with the knee flexed to 20 degrees. No knee can be examined without each of these maneuvers nor can any injury be correctly evaluated by any single one without the others (8:214). Each maneuver has a specific meaning and the presence or absence of findings in each one of them is of lasting signifi cance. Fourth, all areas must be thoroughly palpated, checking for tenderness along the medial and lateral joint lines, the medial and lateral collateral ligaments, the medial femoral condyle, and finally, testing for true joint effusion as contrasted to prepatellar effusion while routinely pressuring the fat pad area for suggestive thickening or tenderness. Only after this complete examination can a working diagnosis be formulated and a program of future rehabilitation be established. 18 Contusions The next step shall be to consider the types of knee injuries encountered, the first of which will be contusions. There are many types of contusions which are the result of a specific incident of impact. These are almost always possible to determine within the first minutes of evalua tion. If the blow was neither sufficiently forceful nor remarkable to cause any counter-joint motion, the player will be able to state this with a positive knowledge that can be depended upon. The site must then be carefully located and inspected, keeping in mind possible confusion with contusions on the femoral condyle and associated neighborhood symptoms that might falsely suggest collateral ligament strain. Also, the "low char lie" with its penchant for supra patellar bursa! bleeding must be kept in mind. Also, bruises of the bony surfaces of the condyles or of the patella itself can occur with local characteristics typical of the bone bruise. Minor Ligament Strains The second type of injury to be discussed will be the minor ligament strains. Minor ligament strains are evidenced first by a history of counter joint force; and second, by distinctly localizeable tenderness along the length of the medial or lateral collateral ligaments. Occasionally this tenderness is limited to a narrow area, but this is diagnostic even in the absences of demonstrable instability either in full extension or at 15 degrees flexion. The most common type of ligament strain is characterized by some 19 degree of demonstrable laxity in the involved ligament with a distinct elas ticity on abduction or adduction at 15 degrees flexion; and in a few days is as tight and stable as ever. Two other types are the medial collateral strain and the lateral collateral strain which are not serious injuries as long as there is full range of motion and full hyperextension in the standing position. Ligament Tear The next injury type that will be discussed is the complete or near complete collateral ligament tear. All the symptoms present in ligament strains are present, but to a greater degree. Abduction or adduction is greatly evidenced without any sense of elasticity at all and full quadriceps stabilization in extension does not alter the degree of lateral instability. In cases of complete collateral tear, the only remaining stability is provided by the medial joint capsule itself. If this is partially torn, there may be so little support that the true limits of lateral angulation of tibia or femur can be downright frightening. If there is joint-line tenderness and limitation of extension or hyperextension by more than five degrees, a cartilage injury must be suspected which is the next injury type to be discussed. Every opportunity should be afforded the knee to spontaneously resolve under these circum stances since past experiences has shown that a large proportion of these subside spontaneously, full range of motion returns, joint-line tenderness 20 disappears, and the football player can return to full participation. Close observations should be maintained on the knee because re-injury or lack of proper attention and care will undoubtedly result in surgery to remove the damaged cartilage. Anterior Cruciate Integrity Now we come to the "drawer sign" and its true meaning, the presence or absence of anterior cruciate integrityo(8:214). This is directly dependent upon an immediate on-the-spot examination which may be the most revealing before any reflex spasms of the hamstrings can develop to completely obscure any possible positive sign. Of additional importance in all knee injuries, but particularly in cases of ligament strain, is the rapidity of quadriceps atrophy. This atrophy is sometimes evident within three or four days and is apparent in the lower-most portion of the bastus medialis, just above the patella. This atrophy is all the more evident because of the usually extraordinary development of this muscle group in the football player or any other com petitive athlete. Ironically, this is usually the last segment of the quadriceps to develop even after the most strenuous competition over many years and is the first to go after injury. It must be restored as soon as possible to stabilize the injured knee. 21 The Retropatellar Fat-Pad Another injury that occurs to the knee is the retropatellar fat-pad to use medical terminology, but is commonly called the "pinched fat-pad" in athletic terms. This injury is characterized by the complain of pain in the kneecap or patella area on hyperextension. A thorough examination may fail to reveal any ligamentous instability, joint-line tenderness, or evidence of internal damage; yet the football player will still complain of pain and increasing discomfort directly behind the patella. Examination of this area reveals an ill-defined soft tissue thickening on both sides of the patella, which is exceedingly tender and is most often termed as a bruise. Under normal circumstances this injury might not be too noticeable and would present only minor discomfort. However, under the stress of compe titive athletics such as in football, the incessant demand on repetitive knee action is certain to pinch the pad sooner or later. Once this pinching occurs, hemorrhaging results and the pinched or damaged tissues swell more and present a larger protruding mass that is painful and tender. During this time the symptoms and the discomfort increase unless activity is pro hibited until this "fat-pad" and the surrounding tissue have had the oppor tunity to return to normal or ordinary corrditfon. Prepatellar Bursitis Prepatellar bursitis is another knee injury that is of concern to football players. Commonly labeled as "water on the knee, " it is 22 characterized by excessive fluid present on the knee, usually caused by a blow or impact to the bursa. This condition is usually eliminated by aspir ation, ice, and compression or use of steroids. Also of great importance is the use of a greater amount of padding or a more absorbent type knee pad to insure adequate protection and prevent further aggrevation or damage to the irritated bursae. There are other injuries .or problems to the knees such as Osgood Schlatter' s Disease and Menisectomy, but since these are not usually an injury caused directly by football, they will not be discussed at this time. Many times they may create difficulties for the football players vJ1 ich are then labeled as injuries caused by football. Also there are the rare but easily recognized dislocation of the patella. This injury is usually lateral and is very painful and disabling. The deformity of a knee whose patella has been displaced laterally out of the condyle notch and is locked into a lateral position is impossible to miss. Immediate replacement by a qualified person such as a physician or team trainer should take place on the spot of the injury before spasms and swelling occur. Any delay in replacement of the patella causes increased pain and difficulty. Immediate attention should follow in the form of X-rays for possible bone chips or fractures and to determine if surgery is necessary for complete treatment and correction of the injury. 23 TREATMENT The next phase to be considered is the treatment and rehabilitation of the knee. First of all, when a knee injury occurs, any good coach, trainer, or doctor should practice a sound "on-the-field" routine. This means that the injured player should be supported or carried from the field either by his teammates or on a stretcher. This is no time for heroic efforts or "tough it out" attempts which will bring the oh's and ah's from the fans and possible increased injury to the player. The fans will clap and the cheerleaders will give him fifteen rahs regardless of how he leaves the field, so think of the injured knee and carry him off the field. The injured knee should be packed in ice immediately and elevated. Hopefully, a team physician or trainer will examine the knee before a great amount of swelling occurs. A compression pad of cotton batting or composition roll is placed over the knee and wrapped with an elastic bandage. Nowhere in athletic medicine are early examination and early treatment more important. It is difficult to examine an injured knee adequately three or four hours after the time of injury. Swelling and muscle spasms occur and make functional tests for stability and flexion unreliable and difficult to perform. Early diagnosis and treatment usually enhance the speed of recovery and most of the time insure more positive results. Knowing how the injury occurred is extremely important in evaluation of the nature and extent of the injury. One of the most important factors is that all knee injuries require immobilization until 24 the exact nature of the injury is determined. If the football player is allowed to walk on an injured knee, changes or increased damage might occur which might mean that the joint cannot be repaired properly even through surgery. In the case of minor knee injury such as partial or minor ligament tears and strains, the boy should be required to use crutches probably for a minimum of three or four days or longer depending on a doctor's prescribed treatment. This is to keep all weight off the knee to prevent aggravating the injury and to allow the swelling to decrease. Many times a cast is required to insure immobilization of the knee joint. The majority of the knee injuries will involve the medial meniscus which is the medical term for the cartilaginous surface of the joint (3:114). Injuries of this type require surgical repair, usually the sooner, the better the outcome of the injured knee. Although a boy may continue to play with cartilage damage, his knee will begin to lock, causing increasing pain, greater damage, and decreasing palying efficiency, which is why surgery is so necessary. In the cases of complete ligament tear, surgery is required to insure proper results in re-establishing the knee. Frequently both the collateral and cruciate ligaments are torn. It is possible for a person in normal life to function with torn cruciates, but not a football player who is subjecting his knee to abnormal stresses. 25 One of the biggest problems that complicate the diagnosis of the knee injury is the almost uselessness of the X-ray. Any broken bone, bone chips, dislocated patella, or similar injury will show up on the X-ray, but not a damaged cartilage or ligament. Therefore, it is imperative that a physician or trainer examine and diagnose the injury or refer the injured player to an orthopedic specialist. Also of equal importance is to be aware of any previous injury that might have been sustained by the knee. The biggest therapeutic improvement in the treating of soft tissue injuries is the use of medications known as enzymes, such as Papase Ananase or similar proteolytic type. These enzymes will reduce the injury and discoloration period by apparently speeding the re-absorption of blood and fluid in the injured area (11 :87). Also, they have a tremendous psychological effect on the injured player because they are fairly new and not too well known by the average person. Another phase in the treatment of the knee is to start whirlpool therapy approximately 48 hours after cessation of treatment with ice. This should be done gradually and is definitely not to be used for a minimum time -period of 48 to 72 hours after the time the injury was sustained. Heat therapy through the use of the whirlpool bath should begin at fairly low or moderate temperatures and gradually increased to a higher degree. However, it is necessary to consult with the physician who is treating the injury since only those of a minor nature will respond while those of a more serious nature will probably require surgery. 26 REHABILITATION Most of the time football players are great patients physiologi cally and psychologically. They are fine physical specimens and usually have been ingrained to accept and live with injury and pain. However, too many times these same players are subjected to unrealistic rehabilitation, probably because of their playing ability, with too little regard for their physical being and the nature of their injury. Hopefully, these situations may be avoided by leaving the boy under the care of the attending physician and thus making him responsible for instituting and supervising the rehabili tation processes. Before a boy is returned to the football field, his knee should be at least as strong as it was before the injury. The main problem that a boy is faced with is atrophy of the muscles supporting the knee, particularly the quadriceps group:. Because the strength and stability of the knee is dependent upon the quadriceps, it is important that this muscle group is at least at its original strength to provide these qualifications. Basically, there is not much reason why extensive atrophy should occur; but it often does, usually because of negligence and unawareness. Even on the day of the injury, work can begin with the quadriceps muscles. When the leg is fully extended, the boy can contract the muscles and hold it for approximately five seconds. No joint movement is involved and a boy should be able to do two or three sets of ten repetitions of this post 27 operative exercise. This is nothing more than a simple isometric exercise and will aid in good muscle tone which is easier to maintain than to rebuild after the muscles have been allowed to atrophy. As soon as the boy's condition permits, he should begin raising the leg in a fully extended position to strengthen the quadriceps. If his leg is in a cast, he can use isometric type exercises by having someone hold the cast whi_le he exerts force upward. The hamstring muscles group can be strengthened in the same manner by simply having the boy roll over on his stomach and force up on the leg against the cast or stay on his back or in a sitting position and exert downward pressure. As soon as possible, attempts to restore full flexion to the knee should be made. The type of injury will determine what treatment and what type of motion should be used. Probably the best exercise to begin with is to have the boy sit on the edge of a table with the lower portion of his leg hanging down over the side and flex the knee. The weight of the leg itself will be enough at the beginning. He should raise the leg until it is straight and then slowly lower it to the original starting position. A boy should start out with five to eight repetitions and gradually increase according to the individual 1 s tolerance and endurance. As soon as the boy has achieved a reasonable range of motion, he should begin to walk. Here is where the team trainer or physician should be consulted. Emphasize the point of not limping or favoring the knee. This will be difficult in the beginning, but it is important when striving to 28 rebuild strength and endurance. After a reasonable length of time, he should begin running to establish stability to the knee. As progress is made, the boy should do a few simple agility drills such as quick starts and stops, cuts, figure eights, and other similar maneuvers. This should be a gradual process determined by the type and nature of the injury and designed to restore the knee to full use. Many types and variations of exercises are used to rehabilitate the knee. Some of them are running and bicycle riding, preferably on a stationary or exercise type mode so that the injured player can be properly supervised. Another exercise to be utilized after flexion is to use weights such as the boot, sandbags, or the quadriceps bench, such as is designed in the Universal Gym Set or the Marcy Gym Set. There are many home-made apparatus such as inner tubes, springs, etc., that can be manufactured to fit the individual budget and facilities and provide adequate exercise. Over-exercising can be as dangerous as under-exercising, but is not so common. Therefore, supervision and guidance are essential so that any attempted exercise is not extended beyond tolerance and results in retarding rehabilitation. The boy must be encouraged to do enough exercise to insure his opportunity to return to the football field. Again, it should be emphasized that a knee strong enough to allow a boy to bowl, dance, and lead a normal everyday life may not be strong enough to withstand the stresses and strains that it will be subjected to in football. 29 Once the player returns to football practice, the injured knee is still of primary concern. How do you support the knee? Externally, the most elaborate devices of steel, plastic, rubber, canvas, and elastic have failed to provide adequate support under the daily demands of football. Granted there are some such as the Palmer knee brace that seem to do a better job than others, but~ are really satisfactory. Ta ping the knee every day seems to provide the best results, but this proves to be costly to some athletic budgets and is not always 100 percent effective. The. main concern should be for the stability of the knee in order to allow the player to participate without excess danger of re-injury. Any boy whose knee is so unstable that it cannot withstand the demands of football which occur when flexed should be prevented from participation regardless of his own desire, parental pressure, or his "importance" to the team. No boy should be subjected to possible permanent injury to win a game or cham pionship. These cases are usually the exceptions rather than the usual cases, but this should be kept in mind. The next item: to look at is the role of football cleats in knee injuries. In the past few years, there has been a great deal of concern, study, and experimenting in the correlation of the knee injury and the football cleats. Hirata reports that originating with Hanley at Bowdoin, who demonstrated a convincing relationship between cleats which were firmly fixed in the ground and subsequent knee injury, there has been many modifications and changes (8:229). The cleats have been shortened, 30 rounded, made into circular discs and flat bars, redesigned like soccer cleats, made from rubber, metal, and plastic, but still knee injuries occur. In some cases, the heel cleats have been replaced by an ordinary shoe heel in an attempt to prevent injury. Knee injuries can and do occur if the heel becomes firmly locked in the ground, thereby creating torsonial forces to the knee (8:235). This is compounded when impact is added, such as a block or tackle, especially from the side. This leaves a great deal of speculation and second guessing to all concerned parties and provides a great selling point to the manufacturers of football shoes. Chapter 4 SUMMARY AND RECOMMENDATIONS Throughout the paper, the writer has endeavored to objectively and thoroughly examine some of the various types of knee injuries that occur in football. A review of related literature showed that while medical and educational authorities were aware of the problem, a definite lack of literature in both areas often leads to haphazard treatment and attitudes by doctors and coaches alike • The main points that were emphasized in the paper were those factors relating to methods of treatment and rehabilitation of the knee. It appears that the most successful cases of knee injuries and their recovery are determined by intelligent and early diagnosis and treatment. It is the tendency of too many of us in coaching to be more concerned with the "toughness" of the player and his immediate return to action on the playing field. With football players, it is especially important to diagnose the injury immediately, treat it, and personally supervise the post-operative care and muscle development. It is not always possible for the average coach to be an outstanding authority on every injury, but it, is possible to apply common sense, concern for the injured player, and some basic knowledge of how to care for athletic injuries. 31 32 Our main concern must be a return to 100 per cent normal func tioning of the player's knee. How this goal is achieved depends upon the coach, his concern and interest, the cooperation and rapport established with a qualified physician, and how each individual case is handled. Bearing in mind the statement from Coach Duffy Daugherty of Michigan State University, "Dancing is a contact sport, football is a collision sport," each one of us is responsible to be aware of the symptoms of a knee injury and the steps to follow to achieve the best possible results. It is recommended that educators, and especially the athletic coach, take a sincere look at his school's policies and procedures regarding the prevention and treatment of injuries occurring on the football field. A baseline knowledge for guidance in the area of injury prevention is a necessary prerequisite to any educational endeavor when one is responsible for the safety of young people. This responsibility is of direct concern to the athletic coach whose influence on the mental and physical well-being of the athlete is powerful. Administrators should allow time for coaches to participate in professional training courses directed toward the safety and health of the student participants. Finally, it is recommended further investigations be made relating to the prevention and treatment of all injuries which might occur during school athletics. The provision of proper and immediate medical attention to the athlete which enables him to continue to participate in a sport he loves and which 33 will prevent him from being forced to live for the rest of his life with a disability that could have been prevented, should be the desire of every athletic coach. BIBLIOGRAPHY 34 BIBLIOGRAPHY 1. Cullen, Charles C. Orthopedic and Surgical Appliances, 8th and Olive Way, Seattle, Washington. 2. Daniels, Arthur S. and Evelyn A. Davies. Adapted Physical Education. New York: Harper & Row, Publishers, 19 65. 3. Dayton, William. Athletic Training and Conditioning. New York: Ronald Press Company, 1960. 4. De Palma, Anthony F. Clinical Orthopaedics. Philadelphia and Montreal: J. B. Lippincott Company, 19 6 2 • 5. • The Management of Fractures and Dislocations. Philadelphia and London: W. B. Saunders Company, 1964. 6. Grant, J. C. An Atlas of Anatomy. Baltimore: The Williams and Wilkins Company, 19 61. 7. Gray, Carolyn E. Textbook of Anatomy and Physiology. New York: The Macmillan Company, 19 63. 8. Hirata, Isao, Jr., M. D. The Doctor and the Athlete. Philadelphia: J. B. Lippincott Company, 19 68. 9. Kerr, Barry A. "Knee Extension Movement," Research Quarterly, Vol. 37, No. 2, May, 1966. 10. Klein, Karl K. The Knee in Sports. New York: The Pemberton Press, Jenkins Publishing Company, 19 69. 11. Larson, Robert L. , M. D. , and Robert 0. Mc Mahan, M. D. "The Epphyses and the Childhood Athlete," The Journal of the American Medical Association, 196:607-612, May 16, 1966. 12. Second Annual Sports Medical Seminar, Seattle, Washington, March, 1969. 13. Slocum, Donald B. , M. D. "The Mechanics of Common Football Injuries," The Journal of the American Medical Association, 170:1640-1646, August 1, 1959. 36 14. Slocum, Donald B., M. D., and Robert L. Larson, M.D. "Rotatary Instability of the Knee," The Journal of Bone and Joint Surgery, 50-1 :211-225, March, 19 68. 15. Spalteholz, Werner, M. D. Hand Atlas of Anatomy. Philadelphia: J.B. Lippincott Company, 1959. 16 • Thorndike, Augustus. Athletic Injuries, Prevention, Diagnosis, and Treatment. Philadelphia: Lea & Febiger, 1948. 17. Trickett, Paule., M. D. Athletic Injuries. NewYork: Appleton Century-Crofts, 19 65. 18. Wakefield, Charles T. , M. D. , Port Orchard Medical Clinic, Port Orchard, Washington. APPENDIX T. •UCKNEA, M.D. (1959) E. MCCONVILLE, M.D. I. CALLAHAN, M.D. J. ELLll:NGE•, M .D. Please note: Signature has been removed due to security concerns EA•T 9-D~DD ORS. MCCONVILLE, CALLAHAN & ELLINGER 701 SIXTEENTH AVENUE SEATTLE, WA19HINlllTCN 99122 Mey 19, 1969 Mr. IBrry Maguire Footbal 1 Coach South Kitsap High School Port Orchard, Washington, 98366 Dear Mr. Maguire : l(y" most sincere apology for the delay in answering your letter. In going over your letter I would suggest that you get hold af a copy ar ''Treatment af Injuries to .Athletes" by Dr. Don O'Donoghue. This book wes first published in 1962 by the W. B. Saunders & Canpeny af Philadelphia end actually is ''The Bible" for doctors who treat injured athletes. I em sure that any doctor friend af yours in the canmunity would have this or make it available to you through e county medical library. At the .Athletic Injury Conference in Oklahane City this year one of the better days was spent on a break dawn on the knee in its relationship to athletic injuries. This included the extensor mechanism, the knee ligaments which wes subdivided into the medial canpirtment, lateral canpartment, end posterior canpartment, es wEi 1 es the cruciete ligaments. A separate day was likewise spent on cartilage injuries. I would think that if you could break down your thesis along these lines you might have a very workable plan • .Another end sanewbat newer book ''The Doctor end the Athlete" by Isao H:lreta, Jr. has recently been published by the J. B. Lippincott Canpaey. This takes up injuries more or less in en enatanicel division. rather than by sports. There h • great deal ar good inf o:rmation in this book end it is readily available to anyone through any reliable book store. If I can be of any fl.Il"ther help to you, kindly call. With kind personal regards,

Knee injuries and their consequencesKnee injuries and their consequences – the impact of impact Swärd, Per 2014 Link to publication Orthopaedics (Lund)]. Department of Orthopaedics, Lund University. Total number of authors: 1 Citation for published version (APA): Swärd, P. (2014). Knee injuries and their consequences – the impact of impact. 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LUND UNIVERSITY PO Box 117 221 00 Lund +46 46-222 00 00 Knee injuries and their consequences – the impact of impact Per Swärd DOCTORAL DISSERTATION by due permission of the Faculty of Medicine, Lund University, Sweden To be defended at Segerfalksalen, BMC, Sölvegatan 17, Lund, on 23 May 2014 at 1 pm Faculty opponent Professor Lars Engebretsen 1 Knee injuries and their consequences – the impact of impact Per Swärd 3 Cover illustration: Mouse knee joint. Bone, hyaline cartilage and meniscus visualised by toluidine blue staining (40 x magnification). Published with the kind permission of Dr. André Struglics. © Per Swärd Lund University, Faculty of Medicine Doctoral Dissertation Series 2014:60 ISBN 978-91-87651-86-1 ISSN 1652-8220 Printed in Sweden by Media-Tryck, Lund University Lund 2014 En del av Förpacknings- och Tidningsinsamlingen (FTI) 4 5 To Catrin 6 7 Contents Abstract 9 Populärvetenskaplig sammanfattning 11 Introduction 13 Preface 13 List of studies 14 Abbreviations 15 Background 17 The knee joint 17 The anterior cruciate ligament 17 Anterior cruciate ligament tears 19 Anterior cruciate ligament injury mechanism 20 Knee injury panorama 22 Osteoarthritis 25 Knee osteoarthritis 25 Post-traumatic knee osteoarthritis 26 Cartilage 27 Synovium 31 The meniscus 32 Bone 32 Inflammation 34 Objectives 39 Specific objectives 39 Subjects 41 Methods 47 Radiography of the knee (Studies I & II) 47 MRI of the knee (Studies I & IV) Alcian blue precipitation (Study III) Electrochemiluminescence (Study III) ELISA (Study IV) Western blot (Study V) Statistical methods Methodological considerations 49 49 50 50 50 51 53 Subjects 53 Imaging 54 Results 55 Radiological characteristics of post- and non-traumatic knee osteoarthritis (Study 1) Alignment and the risk of post-traumatic osteoarthritis (Study II) Cartilage and bone markers and inflammatory cytokines in the acute phase of knee injury (Studies III & IV) Osteochondral fractures and joint inflammation (Study IV) Protease activity in bovine cartilage explants co-incubated with joint capsule and/or mechanically injured (Study V) 55 56 57 58 60 Conclusions 63 Discussion and future perspectives 65 Post-traumatic and non-traumatic knee osteoarthritis The knee injury and the impact Mechanical impact and its role in osteoarthritis initiation after ACL injury Immunity vs biomechanics in driving the OA process after anterior cruciate ligament rupture Concluding remarks 65 66 67 68 73 Tack 75 References 77 8 Abstract Anterior cruciate ligament (ACL) injuries are common, severe knee injuries that result in a high risk of developing knee osteoarthritis (OA) in the affected individuals. As proof of high impact forces applied to cartilage and bone at the time of injury, traumatic bone marrow lesions and osteochondral fractures, located predominantly in the lateral tibiofemoral compartment, are commonly associated with an ACL injury. The subsequent risk of OA may be closely associated with the knee injury mechanism and the panorama of injuries in the knee sustained at the onset of injury. The purpose of this work was to acquire a better understanding of how the initial impact, related to the trauma mechanism of acute knee injuries, may influence acute and chronic knee pathology. In this work it was found that subjects with post-traumatic OA secondary to an ACL injury have more joint space narrowing and more osteophytes in the lateral compartment than in the medial compartment, compared with subjects with non traumatic OA. Furthermore, it was found that an acute knee injury is associated with instant and sustained synovial fluid biochemical alterations within the first month of knee injury, suggestive of increased cartilage turnover and severe joint inflammation. Those subjects who sustained an osteochondral fracture with disrupted cortical bone in association with the soft tissue knee injury had increased joint inflammation. In an in vitro bovine cartilage study, mechanical injury to cartilage increased the matrix metalloproteinase-induced cleavage of cartilage aggrecan. Moreover, findings from this model suggest that the aggrecan degradation may differ between cytokine-stimulated cartilage explants compared with cartilage explants mechanically injured and (or) co-incubated with joint capsule. Conclusively, the findings in this work underline the fact that the initial impact associated with an ACL appears to be important in terms of the risk of developing post-traumatic OA. In addition, this work emphasizes how the acute biological response to injury could be involved in cartilage degradation. A greater understanding of these processes could lead to the improved management of knee injured patients and possibly delay, or even prevent, OA development. 9 10 Populärvetenskaplig sammanfattning Främre korsbandsskador är vanliga, allvarliga och traumatiska knäskador. I kombination med associerade meniskskador och ändrad ledbelastning leder skadan på sikt till att en stor andel individer utvecklar artros i ung ålder. Detta benämns post-traumatisk artros. På kort sikt kan skadan leda till oförmåga att fortsätta sin aktivetet på samma nivå som tidigare. De kraftiga kompressionskrafter över brosk och ben då skenben och lårben kolliderar i skadeögonblicket leder till skador och celldöd i vävnaderna Detta bidrar sannolikt till risken för att utveckla post traumatisk artros. Hos fler än hälften av de skadade individerna kan man med MR visualisera en fraktur i kortikalt ben på skenben och/eller lårben. Skadorna som uppstår i samband med traumat är framförallt lokaliserade lateralt i knäleden och kan tillsammans med blödning i knäleden initiera ett inflammationssvar. Dessutom initieras en läkningsprocess som åtföljs av en ökad omsättning (nysyntes och nedbrytning) av olika broskproteiner. Det broskprotein som framförallt har undersökts under utförandet av detta avhandlingsarbete är aggrekan. Molekylen aggrekan består av ett protein på vilket det sitter ett stort antal sockerkedjor. Dessa är kraftigt negativt laddade och bidrar till broskets funktion genom att attrahera positiva motjoner, vilka genom diffusion drar till sig vatten. Detta leder till ett svullnadstryck och medför att brosket kan motstå de krafter som uppstår när man belastar knäleden. Under artrosprocessen bryts aggrekanet ned av olika enzym som finns i broskmiljön. Framförallt antas så kallade aggrekanaser och matrix metalloproteaser (MMP) ha stor betydelse. Dessa enzym klyver aggrekanmolekylen på olika ställen och genererar olika långa aggrekanfragment som kan mätas i ledväska och i broskmedium. Ett fragment som bildas efter klyvning av aggrekanaser och som analyseras i både arbete III och V är ARGS aggrekan. Ett fragment som bildas efter klyvning av MMP är FFGV-aggrecan (arbete V). Avhandlingen utgår från frågeställningen av vad ett vridvåld i knäleden (knäledsdistorsion) innebär i det akuta skedet och på längre sikt. I första delarbetet gjordes en jämförelse av lokalisationen av artrosförändringar mellan knäleder som har ett definierat trauma (främre korsbandsskada) mot de som inte har detta. Vi fann mer lateralt lokaliserad ledspringesänkning och osteofyter i knäleder där det funnits ett definierat trauma vilket indikerar att det initiala traumat har en viktig roll i den post-traumatiska artrosprocessen. Dessutom kan det vara en viktig 11 klinisk implikation, då det verkar som att efter en främre korsbandsskada utvecklas artros både medialt och lateralt i knäleden. Artros hos individer utan tidigare trauma är oftast lokaliserad medialt i knäleden. I andra delarbetet belyses vilken inverkan knäledens ställning har i samband med artrosutveckling efter en korsbandsskada. Vi fann att individer med varusställning (hjulbenthet) hade mer artros i sitt skadade knä jämfört med de med normal eller valgusställning (kobenthet). Även om skillnaderna mellan grupperna var stora, var de inte statistiskt säkerställda. Mer forskning på området för att utreda om varusställning ökar risken att utveckla artros efter en främre korsbandsskada är indicerad. Arbete III och IV utgår från mätning av ledvätskekoncentrationen av olika brosk-, ben- och inflammationsmarkörer. Vid jämförelse mellan individer med akut knäskada och knäfriska kontroller, visade sig ledvätskekoncentrationer i knäleden av total aggrekan och ARGS-aggrekan vara förhöjda från 1-3 dagar efter skadan upp till 23 dagar efter skadan. Ett annat broskprotein, COMP var förhöjt från 2-3 dagar efter skadan upp till 23 dagar efter skadan. Den nya kunskap som dessa fynd indikerar är att omsättningen av både aggrekan och COMP ökar nästan omedelbart efter skadan. Även flera pro-inflammatoriska proteiner och benassocierade proteiner återfanns i högre koncentrationer i knäleden hos de knäskadade individerna från 0-23 dagar efter knäskadan. I arbete IV undersöktes hur ovan nämnda biomarkörer relaterade till förekomst av MR-visualiserade osteokondrala frakturer där skenben och lårben kolliderade i samband med den främre korsbandsskadan. De inflammatoriska cytokinerna interleukin-8 och tumour necrosis factor-α var förhöjda i ledvätskan hos de individer som ådragit sig en osteokondral fraktur med åtföljande avbrott i det kortikala benet. Sådana frakturer skulle således kunna vara viktiga för det initiala inflammationssvaret på skadan, men även för risken att utveckla artros på lång sikt. Om så är fallet får utvärderas i framtida studier. I arbete V studerades effekterna på aggrekannedbrytning av ett trubbigt våld mot ungt kalvbrosk i laboratoriemiljö samt effekterna av att odla ungt kalvbrosk tillsammans med ledkapsel. Mekanisk skada av brosket ledde till ökad MMP aktivitet, medan en antydan till ökad aggrekanasaktivitet sågs i mekaniskt skadat brosk som odlades tillsammans med ledkapsel. I mekaniskt skadat brosk som behandlades med cytokin sågs mycket kraftig aggrekanasaktivitet, men ingen MMP-aktivitet. Denna avhandling belyser en del processer som skulle kunna ha betydelse för utvecklingen av artros efter en allvarlig knäskada och speciellt efter en främre korsbandsskada. Sammantaget stärker den antagandet att traumat över ben och brosk som sker i samband med att en främre korsbandsskada uppkommer kan ha stor betydelse för risken att utveckla post-traumatisk artros. 12 Introduction Preface Like many diseases, the manifest disease and pathogenesis of osteoarthritis (OA) are multidimensional. The dimensions of OA range from clinical symptoms and macroscopic features of disease through biomechanics to microscopic events at cell, extracellular matrix and molecular level. An increasing amount of knowledge is starting to bridge these dimensions, but there are still many large holes to fill, in order better to understand the disease. The main advantage of post-traumatic OA from the scientist’s perspective is that the time of disease onset is known and the progression of the disease is relatively rapid compared with non-traumatic OA. One of the major drawbacks from the patients’ perspective is that they are affected by the disease at a young age. During my time as a PhD student, I have tried better to understand why and through which processes a severe knee injury can lead to post-traumatic OA. This knowledge is crucial in order to understand the disease and to be able to construct viable treatment options and advice for subjects with severe knee injuries. The main hypothesis underlying the present thesis was that the impact on cartilage, bone and soft tissues of the knee, inflicted at the time of injury, plays an essential role when it comes to the future risk of developing post-traumatic OA. The strength of the present thesis is that, via the papers in the study, it links different clinical parameters and molecular mechanisms that may be important for post traumatic OA development. 13 List of studies I. II. III. IV. V. Swärd P, Kostogiannis I, Neuman P, Von Porat A, Boegard T, Roos H. Differences in the radiological characteristics between post-traumatic and non-traumatic knee osteoarthritis. Scand J Med Sci Sports. 2010;20(5):731-739. Swärd P, Fridén T, Boegard T, Kostogiannis I, Neuman P, Roos H. Association between varus alignment and post-traumatic osteoarthritis after anterior cruciate ligament injury. Knee Surg Sports Traumatol Arthrosc. 2013;21(9):2040-2047. Swärd P, Frobell R, Englund M, Roos H, Struglics A. Cartilage and bone markers and inflammatory cytokines are increased in synovial fluid in the acute phase of knee injury (hemarthrosis)--a cross-sectional analysis. Osteoarthritis Cartilage. 2012;20(11):1302-1308. Swärd P, Struglics A, Englund M, Roos H, Frobell R. Soft tissue knee injury with concomitant osteochondral fracture is associated with higher degree of acute joint inflammation. Am J Sports Med. Published online March 24, 2014. DOI: 10.1177/0363546514524924. Swärd P, Hansson M, Lohmander SL, Wang Y, Grodzinsky A, Struglics A. Evidence of increased protease activity in mechanically injured cartilage co-cultured with joint capsule. Manuscript. 14 Abbreviations ACL Anterior cruciate ligament ADAMTS A disintegrin and metalloproteinase with thrombospondin motifs BMI Body mass index BSP Bone sialoprotein C2C Newly formed epitope after cleavage of collagen at the type II collagen primary cleavage site COMP CRP Cartilage oligomeric matrix protein C-reactive protein CS Chondrotin sulphate DAMP Damage-associated molecular patterns ECM Extracellular matrix HA Hyaluronan KS Keratan sulphate MMP Matrix metalloproteinase MRI Magnetic resonance imaging OA Osteoarthritis OCL Osteocalcin OPN Osteopontin PF Patellofemoral sGAG Sulphated glycosaminoglycan SPARC TGF-β TIMP TNF-α secreted protein acidic and rich in cysteine Tumour growth factor-β Tissue inhibitor of matrix metalloprotease Tumour necrosis factor-α TF Tibiofemoral 15 16 Background The knee joint The knee joint is located between the two other joints of the lower limb; the hip and the ankle. The proximal end of the tibia and the distal end of the femur form the medial and lateral tibiofemoral compartments. The patella and the anterior part of the distal femur form the patellofemoral joint. Together, these joints form the knee joint. High demands are imposed on the knee joint and it has several functions which are essential for human beings to walk, run and jump. Primarily, it enables flexion-extension of the lower limb in the sagittal plane. In extension, full or close to full, the knee must be able to withstand the strong forces imposed on the knee by gravity. In flexion, rotation at the knee enables the leg to position the foot before placement. Small movements in the varus/valgus direction are also possible at the knee joint but only when the knee is flexed. Joint stability during movement is attained by the shape of the articular surfaces, the collateral and cruciate ligaments, the menisci and tendons and muscles crossing the knee joint (Figure 1) [1]. The anterior cruciate ligament The anterior cruciate ligament (ACL) has two functional bundles which connect the femur and the tibia; the anteromedial and the posterolateral bundles, named after their insertion sites on the tibia (Figure 2). These bundles bridge the posteromedial aspect of the lateral condyle and the medial tibial plateau where they insert next to and anterior to the tibial spines. The ACL has an intra-articular location, but it is separated from the synovial fluid by a synovial lining. The main blood supply originates from the femur and specifically from the central geniculate artery [2, 3]. Pacinian corpuscles, Golgi tendon organs and Ruffini endings are mechanoreceptors present in the ACL which contribute to the proprioceptive sense [4]. The extracellular matrix (ECM) of the ACL contains collagen types I, II, III and V, elastin and proteoglycans. The tensile properties of the ACL are mainly related to bundles of collagen type I and cross-linking of these [5, 6]. In the normal 17 ACL, fibroblasts reside along collagen bundles and are important for normal ligament turnover. Moreover, cells with progenitor potential are present [6]. The function of the ACL is to provide tibiofemoral joint stability in anterior-posterior translation and in internal-external rotation [7]. The ACL also restrains movements in the varus-valgus direction. The anteromedial and posterolateral bundles of the ACL act in synergy to stabilise the knee joint through its entire range of motion. In flexion, the anteriomedial bundle is tauter; in extension, the posterolateral bundle is tauter [3]. The combination of valgus and internal rotation of the tibia has been shown to increase ACL strain more than either motion alone [8]. Figure 1. Posterior view of the left knee showing the anterior and posterior cruciate ligaments and the menisci. The image which is from the 20th US edition of Gray's Anatomy of the Human Body was originally published in 1918 and has been transferred into the public domain. 18 Figure 2. Schematic drawing of the double-bundle ACL anatomy. AM, anteromedial bundle; PL, posterolateral bundle. Published with kind permission. © C. Kartus. Anterior cruciate ligament tears In Sweden, football (soccer) is the most common activity associated with ACL injury for both men and women. The second most common activity associated with ACL injury is downhill skiing for women and floorball for men (www.aclregister.nu). The incidence of ACL tears was shown to be 81 per 100,000 subjects aged between 10 and 64 years [9]. Based on these numbers, some 6,000 ACL injuries occur in the Swedish population every year, of which ~3,000 ACLs are surgically reconstructed. The indications for ACL reconstruction in Sweden are symptoms of instability and the failure of conservative treatment (www.aclregister.nu). In the USA, approximately 200,000 ACL reconstructions 19 are performed every year [10]. Women are known to be more susceptible to ACL rupture compared with men, and are injured at a younger age [11, 12]. Anatomic, neuromuscular and hormonal variations between men and women have been proposed to explain this observed difference [13-16]. From the individual’s perspective, the injury may, in the short term, lead to knee dysfunction and an inability to continue sports participation at the same level as pre-injury. In a recent review, it was summarised that, although normal to nearly normal knee function was regained in most ACL-reconstructed individuals, a relatively small number of individuals returned to their pre-injury activity level and competitive sports [17]. Psychological factors, including fear, lifestyle changes and personality, have an impact on why subjects do not return to their pre-injury sports activity after ACL reconstruction [18]. In professional sports, the return to play after ACL injury is much greater and Waldén et al. [12] reported that 94% of elite level football players returned to training within 10 months and that 89% participated in a match within 12 months after ACL reconstruction. An ACL tear also leads to a high risk of developing OA of the injured knee at a young age [19-22]. ACL re-injury/graft rupture and the high risk of contralateral ACL injury are other important issues that require consideration when advising an individual to return to sport [23]. In a reasonably sized study, in terms of the queries tested, it was reported that 4.5% sustained a graft rupture and 7.5% sustained a contralateral ACL injury during the five-year follow-up after ACL reconstruction. Importantly, 29% of individuals younger than 20 at the time of the first ACL injury sustained an ACL injury to either knee during follow-up [24]. Taken as a whole, the high risk of ACL injury, specifically in young women, and future complications related to the injury are regarded as one of the major problems in sports medicine [25]. Anterior cruciate ligament injury mechanism In the literature, the ACL injury mechanism is most often described as contact or non-contact. This definition may be misleading, as most ACL injuries that occur in contact sports are associated with a “non-contact” mechanism [26, 27]. A contact ACL injury mechanism typically occurs in American football, when the subject plants his foot and, at the same time, is tackled at the knee from the lateral side, resulting in a valgus collapse of the knee joint. The injury panorama of this injury mechanism often results in lesions of the ACL, medial collateral ligament and medial meniscus, referred to as the O’Donoghue triad [28]. Several mechanisms that may result in a non-contact ACL injury have been proposed. Most typically, the injury occurs as the athlete plants the foot with the knee in slight flexion and 20 during landing, side-cutting or deceleration. In this position, knee valgus motion, internal rotation of the tibia towards the femur or external rotation of the femur towards the tibia, combined with anterior translation of the tibia, ensue. This leads to high strain in and the rupture of the ACL [26, 29, 30]. This ACL injury mechanism, also known as the pivot shift injury, induces simultaneous lateral tibiofemoral compartment subluxation and combined compressive force, explaining the typical location of bone marrow lesions, on the posterolateral tibial plateau and the midportion of the lateral femoral condyle [2]. The impact site on the lateral femur is related to the degree of knee flexion at the time of injury. With the knee in a high degree of flexion or extension at the time of injury, the lateral tibia impacts the posterior or the anterior part of the lateral femur respectively [2]. Differences in the ACL injury mechanism between the sexes have been described. Investigating basketball players, Krosshaug et al. [31] reported that a valgus collapse in association with the injury was five times more common in women. A lower incidence of meniscal tears associated with the ACL injury has been indicated in women [32], which could be related to differences in injury mechanism between men and women. Furthermore, besides from showing that young age was associated with more traumatic bone marrow lesions on the lateral femoral condyle, it was in a study by Bisson et al. [33] demonstrated that male gender associated with mild traumatic bone marrow lesions on the lateral femoral condyle and tibial plateau. Male gender also associated with moderate and severe traumatic bone marrow lesions on the lateral femoral condyle. These findings may further highlight gender-specific differences in ACL injury mechanism and as a result, factors other than valgus collapse may be of greater importance for compressive injuries to soft tissues and bone associated with ACL injury. Even if they were not investigating bone-bruise patterns, Fridén et al. [27] proposed that the degree of compression between the tibia and femur was related to weight bearing or non-weight-bearing at the time of injury. A non-weight-bearing ACL injury mechanism, which typically occurs when skiing, was associated with larger numbers of intact menisci, indicating a lower degree of joint compression in this type of injury [27]. In a large-scale investigation of 525 subjects, younger age and not jumping at the time of ACL injury were associated with a bone bruise [34]. Jumping at the time of injury may indicate a non-weight-bearing ACL injury and these findings are thus in line with the hypothesis put forward by Fridén et al. [27]. 21 Knee injury panorama An acute knee injury with joint effusion and intra-articular bleeding (hemarthrosis) suggests significant intra-articular pathology. Anterior cruciate ligament tears, meniscal lesions and lesions of the medial collateral ligament are common after rotational knee injury [9]. In subjects (n=1,145) with an acute knee injury in whom MRI (magnetic resonance imaging) was performed a median of eight days after the trauma, 52% had sustained an ACL injury, 17% had transient patellar dislocation and 28% a medial collateral ligament tear. Among the ACL-injured subjects, 55% also sustained an associated meniscal tear [35]. These findings are in line with previous investigations of smaller study samples, regarding both the panorama of knee injuries [9] and the high prevalence of meniscal tears concomitant to the ACL tear [36, 37]. The majority of studies and the historical view indicate that lateral meniscal tears are more common than medial tears after ACL injury [36, 38-40]. However, recent studies have described a similar prevalence or even more medial than lateral meniscal tears in association with ACL injury [9, 37]. In a recent MRI-based study, the most common meniscal tear associated with the ACL injury was a longitudinal tear of the posterior horn of the medial meniscus [9]. The authors speculate that these tears may be difficult to detect during routine arthroscopy and could progress and produce symptoms in an unstable knee [9]. Isolated or multiple articular cartilage lesions are also a frequent finding after ACL injury [32, 41]. Posterolateral knee injury, which is relatively uncommon, is an important diagnosis which, if left untreated, can lead to severe knee disability [42, 43]. In almost all individuals, an acute knee injury also leads to a collision between the tibial plateau and the femoral condyle, as visualised using MRI by traumatic bone marrow lesions at the site of impact. These have been described as “fingerprints of injury mechanism”, or “kissing lesions” and have been detected in almost all subjects who have suffered an ACL tear [2, 44, 45]. Typically, the collision occurs in the lateral tibiofemoral compartment between the non-articular posterolateral tibial plateau and the articular midportion of the lateral femoral condyle [44, 46, 47]. Depending on the injury mechanism, other locations of traumatic bone marrow lesions may be present (see above). Traumatic bone marrow lesions in the medial tibiofemoral compartment have been ascribed to the contre-coup mechanism, but they are less common and are mostly associated with bone marrow lesions of the lateral compartment [48]. It should be noted that medial bone marrow lesions are commonly found in subjects with a combined ACL and posterolateral knee injury [42]. At the site of impact between tibia and femur, more than half of ACL-injured subjects also sustain a traumatic osteochondral fracture [39, 44]. These fractures 22 are prevalent in the lateral tibiofemoral compartment overlying the traumatic bone marrow lesions and present with or without the disruption of cortical bone (Figure 3). They indicate strong impact forces between the tibia and femur at the time of injury and correlate with the size of bone marrow lesions [39, 44] and the likelihood of associated meniscal tears [39]. The traumatic bone marrow lesions represent trabecular fractures, bleeding or oedema. In one study, human biopsy samples of cartilage and subchondral bone overlying MRI-detected bone bruises were obtained at a median of 4.5 weeks after ACL injury. Glycosaminoglycan loss and chondrocyte necrosis were observed in the overlying cartilage. In the subchondral bone, osteocyte necrosis was indicated by empty lacunae [49]. Figure 3. Magnetic resonance images of knees used in Study IV. Upper row: proton density T2 weighted sequence and bottom row: short-tau inversion recovery (STIR) sequence of knees with osteochondral fractures with disrupted cortical bone in the femur (yellow arrow) and without disrupted cortical bone in the femur (blue arrow). The STIR sequence images (bottom row) clearly show the surrounding post-traumatic bone marrow lesion of the osteochondral fracture above, indicating traumatic impact forces (white arrows). 23 24 Osteoarthritis Knee osteoarthritis Knee OA is more common in women and knee OA incidence and prevalence increase with increasing age. Knee OA may be isolated, or may be part of generalised OA, defined as affecting the hands and at least one large joint, or affecting three or more joints [50]. Obesity has been shown to be a highly important and modifiable risk factor for OA development and progression [51]. Adding to the complexity of the disease, the metabolic syndrome and two of its components, central obesity and hypertension, are also associated with the incidence of severe knee OA requiring total knee replacement, independent of body mass index (BMI) [52]. Systemically increased factors derived from visceral adipose tissue have been shown to increase the risk of hand OA and may also be involved in the pathogenesis of knee OA [53]. Today, knee OA is a leading cause of global disability. The ageing population and increasing rates of obesity worldwide forecast an increasing need for health care related to knee OA in the future [54]. Symptomatic knee OA affects almost 7% of the US population 50-84 years of age, of which approximately 50% are obese [55]. Petersson et al. [56] reported that 1.5% of individuals 35-54 years of age, living in a district in the southwest of Sweden, had symptomatic non-traumatic knee OA. The rates of radiographic knee OA are much higher. In the elderly (over the age of 60 to 75), the prevalence of radiographic OA was shown to be between 31-45% [57-59]. There may, furthermore, be ethnic differences regarding knee OA location. For example, in the Chinese, the lateral tibiofemoral compartment is affected more often than in Caucasians [60]. Importantly, OA has a large impact on quality of life and was estimated to reduce the remaining quality-adjusted life expectancy in persons with knee OA by 10-13%, with the higher rates applying to younger individuals with knee OA [55]. As indication of the increasing incidence of symptomatic knee OA, the numbers of total knee replacements performed in the USA more than doubled from 1999-2008. In younger individuals (45- to 64-year olds), the numbers more than tripled. In addition to increasing obesity rates, this increase may be related to wider indications of surgery and increasing numbers of severe knee injuries in young individuals [61]. An increased understanding of knee 25 OA risk factors, how best to treat symptoms and find treatments that can prevent or stop OA progression is needed. Apart from age, gender and obesity, also genetics, knee injuries and abnormal joint loading influence the risk of developing knee OA. Seven genetic variants associated with knee OA or total knee replacement have been identified [62] and 39% of the risk of developing knee OA has been attributed to genetic variation [63]. The possibility that abnormal, or overly high loads can lead to progressive cartilage degradation was indicated by the increased risk of knee OA in occupations where there is frequent heavy lifting, kneeling or squatting [64]. Moreover, malalignment has been shown to increase the risk of OA [65, 66] and elderly male former elite athletes engaged in non-impact sports have an increased knee OA prevalence after adjustment for previous knee injury, age, gender, BMI and occupational load [67]. Post-traumatic knee osteoarthritis As things stand, some 12% of the total OA burden has been ascribed to post traumatic OA [68]. It has been proposed that the incidence of post-traumatic OA is increasing in relation to increased numbers of individuals engaged in sports and over the last few decades, the increase in sports participation has been substantial. In the USA, the number of women participating in high-school sports has roughly doubled every decade [46]. Instability is as a major cause of disability after ACL injury [69]. This has influenced the treatment of ACL injuries and ACL reconstruction has been a preferred treatment, with the aim of re-establishing knee stability [70]. However, no differences in the long-term risk of OA development have been shown between ACL-injured subjects treated with or without primary ACL reconstruction in recent systematic literature analyses and from the early results of a randomised controlled trial [19, 21, 71, 72]. Associated injuries may be of greater significance for the long-term prognosis. In a review by Øiestad et al. [21], it was concluded that the prevalence of knee OA after an isolated ACL injury was 0-13%. The prevalence of knee OA after an ACL tear with an associated meniscal tear was 21-48% [21]. Differences in the classifications relating to the radiographic grading of OA between different studies have led to difficulties juxtaposing the current knowledge [21, 71]. In a recent meta-analysis only including studies using the Kellgren & Lawrence classification and with a minimum follow-up time of 10 years, it was shown that non-ACL-reconstructed knees had an increased relative risk of developing any grade of OA. However, the relative risk of progression to moderate or severe OA tended to be higher in ACL-reconstructed knees [71]. 26 Cartilage The proximal tibia, the distal femur and the patella are covered by a thin layer of hyaline cartilage, forming the articular surfaces of the knee joint. Normal cartilage is avascular, aneural, with no lymphatic vessels and the only cell type found in cartilage, the chondrocyte, obtains nutrition mainly from passive diffusion from synovial capillaries (see below). In normal articular knee cartilage, only 1-3% of the wet weight tissue consists of chondrocytes [51]. Some 70% of the tissue consists of water, whereas 20% of the wet weight is collagen (mainly type II; the fibril-forming collagen of cartilage) and approximately 5% is aggrecan [73]. The main function of cartilage is to distribute the load applied to the underlying bone and to allow movements of low friction at the knee joint [74]. These functional properties are preserved by the chondrocytes which maintain cartilage hemostasis by inducing proteolysis and the production of non-fibrillar collagens, proteoglycans and other non-collagenous molecules, as a reaction to biomechanical and biochemical stimuli [75]. The capacity of cartilage to absorb and distribute high loads at a specific site is related to the composition of cartilage ECM and specifically to the integrity of the fibrillar collagen and aggrecan networks that are present. Aggrecan forms large aggregates by binding to hyluronan and is substituted by negatively charged sulphated glycosaminoglycans (sGAGs) [76]. The high negative charge attracts counter-ions and, by diffusion, water is attracted to the aggrecan molecule. This results in a swelling pressure in cartilage which is retained by the tensile strength of the collagen fibril network and gives cartilage the ability to withstand compressive loads [76]. The fibrillar collagen and aggrecan networks, on the other hand, are dependent on other molecules present in the cartilage ECM, such as cartilage oligomeric matrix protein (COMP), non-fibrillar type IX collagen and members of the small leucin-rich repeat protein family. Important functions of these molecules include the regulation of collagen fibril formation and other collagen networks in the cartilage ECM. They also enable interactions between different ECM molecules and interactions with the chondrocytes [76-78]. Type II collagen has a long half-life (about 100 years) and its degradation is believed to be practically irreversible [79]. Several collagenases are able to cleave fibrillar type II collagen, of which the matrix metalloproteinase (MMP)-13 is believed to be the most important [51, 77]. Cleavage at the primary cleavage site in type II collagen by these collagenases generates two fragments, of which one can be detected by a neo-epitope antibody (against the newly formed epitope; named C2C). Interestingly, increased synovial fluid concentrations of C2C are associated with pre-radiographic cartilage lesions in the knee joint of ACL-injured subjects [80]. Aggrecan has a more rapid turnover. The cleavage of aggrecan can 27 be mediated by several proteolytic enzymes (Figure 4). The aggrecanases-1 and -2 (ADAMTS-4 and -5; a disintegrin and metalloproteinase with thrombospondin motifs), and, secondly, the MMPs are believed to be most important [81-84]. Another somewhat abundant protein in cartilage is COMP, which is believed to be important for the fibrillation of type II collagen in cartilage and for stabilising the collagen network in the adult cartilage. Its turnover is increased during the early progression of OA [77]. The turnover of COMP is also increased after an acute knee injury, as observed by increased synovial fluid concentrations from within one week of injury up to several years later [85]. HA G1 ADAMTS-4/5 G2 IGD G3 L MMP KS CS Figure 4. Aggrecan is bound to hyaluronan (HA); an interaction stabilised by the link protein (L). Aggrecan is composed of three globular domains; G1 (N-terminal side), G2 and G3, an inter globular domain (IGD), one region rich in keratan sulphate (KS) and two regions rich in chondroitin sulphate (CS1 and CS2). Several enzymes have been shown in vitro to cleave aggrecan in the IGD domain [81, 83, 84, 86]. Aggrecanase cleavage at the TEGE373↓374ARGS site and MMP cleavage at the IPEN341↓342FFGV site have been demonstrated in humans [81, 83, 84, 87-89]. Suggestive of rapid aggrecan turnover by increased aggrecanase activity, increased concentrations of ARGS-SELE and ARGS-CS1 fragments have been shown in the synovial fluid of subjects with acute knee injury. Moreover, increased aggrecanase cleavage in the aggrecan CS2 domain generates GRGT-G3, GLGS-G3 and AGEG-G3 fragments [88]. Figure reproduced with the kind permission of Dr. André Struglics. Cartilage can be divided into regions of different ECM organisation and molecular content, as well as chondrocyte organisation, shape and function throughout the depth of cartilage: the superficial (tangential), central (intermediate) and deep (radial) layers of cartilage [90]. The transitional zone between the cartilage and subchondral bone is called the calcified cartilage layer and it creates a barrier and 28 attachment site between cartilage and subchondral bone [91]. Detected differences in cell appearance and function between the different layers of cartilage include the following. (1) The number of chondrocytes per cartilage volume is higher in the superficial zone compared with deeper layers and the chondrocytes appear flattened and are aligned horizontally parallel to the joint surface [92, 93]. The superficial zone chondrocytes, furthermore, produce lubricin, as opposed to the deeper layers [94]. There is also a high content of collagen fibres running parallel to the cartilage surface, although there may be differences between weight- and non-weight-bearing regions (see below) [7]. (2) In the central layer, the chondrocytes are rounder and the proteoglycan content is higher compared with the superficial or deep zones [92, 95]. (3) In the deep layer, the collagen fibres are thicker and round chondrocytes are aligned in columns [90, 92]. In addition to these depth-related differences, the cartilage ECM also differs depending on the proximity to the chondrocytes. With an increasing distance from the cells, ECM is classified as pericellular, territorial and interterritorial, with apparent differences in ECM organisation and function [77]. Mesenchymal progenitor cells, which could have the potential to regenerate focal cartilage defects, have been found in cartilage [96]. Different cartilage regions in the knee joint, furthermore, show differences in cell and ECM organisation attributed to the different mechanical loads between regions. Rolauffs et al. [93] detected four distinct superficial zone chondrocyte patterns; strings, clusters, pairs and singles in the knee joint. Different joint surfaces of the knee were typically dominated by only one of these four patterns. The predominant pattern of the femoral condyles, meniscus-covered medial tibial plateau and patellofemoral grove were strings, pairs and clusters respectively. Central regions of the tibial plateau are associated with a less organised collagen fibre orientation, which could be a consequence of high compressive loads over this region. On the other hand, peripheral regions of the tibial plateau (i.e. beneath the menisci) are associated with a more organised collagen fibre orientation more parallel to the surface. This could be a consequence of the high tensile stresses to which these regions are exposed [7, 97]. Cartilage and knee osteoarthritis One of the main features of knee OA is the loss of articular cartilage. Over the years, much of the research on OA has therefore focused on the events involved in cartilage degradation. At cartilage level, OA development is associated with cartilage fissures, swelling, chondrocyte hypertrophy and phenotypic changes in the chondrocytes. As the disease progresses, cartilage thinning and the exposure of subchondral bone occur [51]. Several important clues to the way cartilage is affected during the different stages of OA development and progression have been 29 identified during the past few decades. Proteases able to degrade cartilage constituents have been highlighted and MMP-13 and ADAMTS-5 in particular [79]. In models using genetically modified mice, deleting the catalytic domain of ADAMTS -5 protects the cartilage from degradation [98]. Furthermore, knock-in induced resistance to cleavage at the wild type ARGS↓TEGE-aggrecan site significantly protects the cartilage from degradation [99]. Induced MMP-13 deficiency also inhibits cartilage degradation [100]. Underlining the complexity of the post-traumatic OA mouse model, at least 29 different genetic modifications have been shown to be protective of cartilage erosion and 19 have been shown to increase cartilage erosion in different OA models [101]. Human OA is characterised by a whole joint disease and inducing MMP-13 deficiency did not lead to reduced osteophyte formation in a mouse OA model [100]. Many other molecular mechanisms have been implicated in OA pathogenesis and recent studies have, for example, indicated important roles for tumour growth factor (TGF)-β and complement activation in OA pathogenesis [51, 102, 103]. Cartilage and post-traumatic knee osteoarthritis Acute knee injuries are associated with radiographic OA progression and joint space narrowing indicative of cartilage erosion (see above). One major limitation of using radiographic signs to detect cartilage injury is the relatively long time from injury until these changes occur and the fact that changes indicating cartilage loss, such as joint space narrowing, may be related to other factors, such as the integrity of the menisci [104]. Recent advances in MRI have led to an increase in our understanding of early post-traumatic changes in cartilage which may precede post-traumatic OA development [105, 106]. Compositional cartilage MRI (delayed gadolinium-enhanced imaging of cartilage (dGEMRIC), T1-rho and T2 mapping) can depict information on the composition of cartilage. Whereas dGEMRIC and T1rho may distinguish changes in cartilage proteoglycan content, T2 mapping relates to the cartilage water content and indirectly to type II collagen content and orientation [105]. Before the development of these techniques, cartilage biopsies revealed important information on changes in cartilage composition after ACL injury. Suggestive of collagenase activity, biopsy samples acquired from the non weight-bearing articular cartilage of the intercondylar notch show collagen denaturation and the cleavage of type II collagen less than and more than one year post-ACL rupture [107, 108]. Interestingly, an increase in cartilage GAG content was also observed [107]. At time points after one year, lower type II collagen content in the cartilage of the intercondylar notch was observed [108]. Biopsy of the cartilage adjacent to bone marrow lesions on the lateral femur showed a decrease in GAG in median 4.5 weeks after ACL injury [49]. In line with these findings, Li et al. [109] showed elevated T1rho values (indicating GAG loss), of 30 the posterolateral tibial cartilage in ACL-injured knees at baseline. Tiderius et al. [110] showed that the estimated GAG content (assessed by dGEMRIC) was lower in both the medial and lateral femoral cartilage within mean three weeks after ACL injury. At two-year follow-up, recovery but not normalization, was observed in the lateral tibifemoral compartment whereas the estimated GAG decrease in the medial tibiofemoral compartment seemed to remain at a constant low level [111]. Potter et al. [41] demonstrated MRI-detectable cartilage lesions at the time of ACL injury in 100% of patients, primarily affecting the lateral tibial plateau and secondly the lateral femur. A progressive increase in cartilage lesion severity was observed with time lapsed after injury [41]. Synovium The non-bony cavity of the knee joint is enclosed by the synovium. It consists of the intima, a continuous layer of macrophages and specialised synovial fibroblasts (synoviocytes), and the subintima, which is the underlying tissue. The subintima is a fibrous ECM where blood and lymph vessels, nerves, stationary fibroblasts and immune cells reside. The synovial fibroblasts have a distinct phenotype. Of particular importance to the joint environment, they experience high activity from an enzyme which converts UDP-glucose to UDP-glucoronate, an essential component for hyaluronan synthesis [112]. Furthermore, synovial fibroblasts, along with superficial zone chondrocytes, produce lubricin, which is particularly essential for the boundary lubrication of cartilage [113]. The main route for nutritional access to the avascular cartilage is passive diffusion from capillaries of the synovium. They are located in the subintima, just beneath the intima. The capillary endothelial cells form a size-selective barrier allowing the flux of water, nutrients and proteins into the joint cavity. The synovial fluid-to plasma ratio of plasma proteins decreases as the molecular radius of the protein increases [114]. Importantly, the cells of the intima are loosely connected and there is no basement membrane. As a result, the interstitial fluid of the synovium and the synovial fluid form an unbroken continuum [115]. The efflux of molecules from the knee joint occurs through drainage via the lymph vessels for molecules ~2 to ~10 nm in size. Smaller molecules, for example, some cytokines, can also access the circulation via diffusion into capillaries. Larger molecules, such as hyaluronan and large aggrecan fragments, may be restricted from efflux via the lymph vessels. At high intra-joint pressures, these large molecules could create a filter cake, increasing the outflow resistance across the synovium and limiting fluid escape from the joint [115, 116]. In the event of synovitis (see below), the 31 size selectivity of the endothelial barrier is decreased, leading to an increase in the influx of large proteins and joint effusion [117]. The meniscus The meniscus is a crescent-shaped fibro-cartilaginous tissue rich in collagen type I. The molecular constituents of the meniscus are quite different from those of cartilage. For example, compared with knee-joint hyaline cartilage, the collagen fibrils are thin, the amount of aggrecan and chondroadherin is low, whereas the amount of asporin is high [118]. The tensile strength and function of the menisci are related to the circumferentially oriented collagen fibres woven together with radial fibres [119]. In principle, the menisci play an important role in reducing cartilage loads by distributing the load between the femur and tibia over a larger area. Compromising this function, such as in the case of meniscus tear or meniscectomy, leads to increased peak and average loads over the tibiofemoral cartilage [120] and a high risk of OA [19, 121, 122]. The increased loading of tibial cartilage is closely related to both the amount and type of medial meniscectomy (anterior, posterior or longitudinal) [120]. The long-term outcome of ACL injury is closely related to the integrity of the menisci (see above). However, subjects with an ACL tear (isolated or combined) present with the first radiographic signs (joint space narrowing) of cartilage degradation approximately ten years prior to subjects with an isolated meniscal tear [123]. Not only the status of the menisci at index injury but also the risk of secondary meniscus injury are important for the risk of future tibiofemoral OA after ACL injury [124]. Meniscus injury also appears to be important when it comes to developing patellofemoral OA [125, 126]. The menisci and specifically the medial meniscus may contribute to joint stability and restrain anterior translation in the ACL-deficient knee but not in knees with an intact ACL [127, 128]. This renders the medial meniscus susceptible to tears in the ACL-deficient knee and this has been advocated as an important reason to perform ACL reconstructive surgery [129]. Bone The bony parts of the knee joint, the femur, tibia and patella, have a dense and compact outer structure, the cortical bone, and a porous inner structure, the trabecular bone. In the knee, trabecular bone and cartilage are separated by the 32 osteochondral plate; a thin layer of cortical bone (the subchondral plate) and the calcified cartilage layer [130]. Bone is a metabolically active tissue. After the peak bone mass has been reached at the age of 20-30 years, bone remodelling is characterised by a higher bone resorption rate compared with the corresponding bone formation. This results in a net loss of bone mass [131]. Bone and knee osteoarthritis Bone-related alterations associated with OA include bone marrow lesions, osteophytes, subchondral bone sclerosis, cyst formation, tidemark duplication and thickening of the calcified cartilage layer [130]. Microcracks through the osteochondral plate, ingrowth of nerves, vessels and endothelial proliferation within the non-calcified cartilage are associated with OA and could increase cross talk between cartilage and bone [132, 133]. These changes, in combination with changes in bone homeostasis, may induce cartilage erosion [103, 133, 134]. An important role for increased TGF-β signalling in the subchondral bone has been suggested [103]. It is unknown whether pathological changes in bone precede or follow osteoarthritic changes at molecular level in cartilage. The parallel progression of disease in both tissues is, however, a likely scenario. This was illustrated by the increase in both serum bone sialoprotein (BSP) and COMP in subjects with chronic knee pain who went on to develop early radiographic knee OA [135]. The serum concentrations of these proteins were, furthermore, higher in subjects with bone scan abnormalities [136]. Even though these studies indicate parallel alterations in cartilage and bone homeostasis during the course of early OA development, abnormal alterations in bone typically precede those in cartilage, as visualised by different imaging techniques. For example, osteophyte formation and scintigraphic changes indicative of increased bone turnover typically occur before joint space narrowing [137]. Changes in bone shape, furthermore, predict the onset of radiographic OA [138]. These differences could, however, be related to the higher metabolic rate in bone compared with that in cartilage and the more rapid response of bone to changes in joint load. Bone and post-traumatic knee osteoarthritis In line with OA seen in subjects without previous knee joint trauma, early signs of bone disturbance are also evident after severe knee injury. Bone mineral loss in the knee of ACL-injured subjects was demonstrated after ACL reconstruction [139]. 33 In a study population of 121 subjects followed prospectively after ACL injury, it was recently shown that bone shape changes of femur, tibia and patella could be detected by advanced analyses methods applied to sequential MR images already after two years. Preliminary analyses suggest that these changes could relate to osteophyte formation. [140]. In the same study population, changes in articular bone curvature were observed within three months of the injury [141]. Buckland Wright et al. [142] demonstrated thickening of horizontal trabeculae and a high prevalence of osteophytes in the medial tibial compartment within four years of ACL injury. Taken as a whole, these findings indicate changes in bone metabolism and remodelling at an early stage after ACL injury. In subjects with an acute knee injury, cartilage and bone involvement occurs instantly, as the tibia and femur collide, resulting in cartilage injury, bone marrow lesions and osteochondral fractures [41, 44, 49, 143]. Traumatic bone marrow lesions gradually decrease in size, but fewer than half resolve within one year after the injury [144]. In most studies, their presence has not been shown to correlate to clinical outcome [34, 145]. Anterior cruciate ligament-injured subjects with a bone marrow lesion of the medial tibia, a trabecular fracture of the lateral femur or a more severe intra-articular lesion, i.e. osteochondral fracture, may, however, have poorer clinical outcome scores [39, 146, 147]. Johnson et al. [146] observed that a trabecular fracture, by the authors termed a geographical bone bruise [47], on the lateral femur was associated with the increased size and duration of effusion, a time-lag in time until the normal range of motion was regained and increased pain in the acute phase of ACL injury. Inflammation Inflammation may play an important role in the pathogenesis of OA [148]. Indicative of this, synovitis, which has been shown to be reflected by increased plasma C-reactive protein (CRP) concentrations, is a prevalent finding in OA [149]. More importantly and underlining the importance of inflammation in OA, synovitis has been shown to be prognostic of MRI detected cartilage loss in subjects without radiographic OA [150]. Increased numbers of several inflammatory cell populations have been detected in the OA joint capsule, of which macrophages, T cells and mast cells are most abundant [151]. Of particular interest, mast cells have been found at higher cell numbers in OA compared to RA joint capsule and their mediators (histamine and tryptase) at higher concentrations in the synovial fluid in subjects with OA compared to those with RA [151, 152]. Inflammatory and synovial cells may contribute to joint synovial and cartilage 34 inflammation by producing cytokines, prostaglandins and proteases, such as neutrophil elastase, aggrecanases and different MMPs [153-157]. Proteases, which are essential for the degradation of cartilage molecules, can be induced and activated by inflammatory molecules. Numerous in vitro studies have demonstrated aggrecanase and MMP activity (including collagenase activity) and injurious effects on cartilage structure and chondrocyte function (survival) in the presence of pro-inflammatory cytokines [158-161]. In fact, adding tumour necrosis factor (TNF)-α to a cartilage explant in vitro can lead to the total dissolution of the explant mediated through the upregulation of proteases in the chondrocytes [74]. In vivo, in a mouse model, Malfait et al. [162] showed that the intra-articular administration of TNF-α led to the rapid degradation of the cartilage aggrecan by the induction of aggrecanase activity. The aggrecan degradation was reversible and these findings are in line with the work of others [163]. Typically, collagen degradation, which is irreversible in in vitro cartilage explant systems, does not begin until after several days of inflammatory stimuli and not until most aggrecan molecules have been degraded [79]. Further emphasising the protective role of intact aggrecan in the in vitro cartilage explant system, aggrecanase inhibition not only prevented interleukin (IL)-1-induced aggrecan degradation but also prevented collagen degradation [160]. However, in more complex systems, increased collagen degradation may parallel that of aggrecan. In a horse model, increased synovial fluid concentrations of the C2C epitope were detected within 24 hours of lipopolysaccharide-induced joint inflammation, suggestive of increased collagenase activity [164]. Also suggesting increased protease activity, cross linked peptides of type II collagen were detected in the synovial fluid early in the acute phase of knee injury [165]. The fact that a “soup” of several pro-inflammatory cytokines or molecules leads to more rapid cartilage degradation was furthermore observed when human and bovine cartilage explants were exposed to both interleukin (IL)-1 and plasminogen compared with when explants were exposed to IL-1 alone [166]. Moreover, the combined effects of TNF-α, IL-6 and sIL-6r on human and bovine knee cartilage explants caused more GAG release than the individual cytokines alone [161]. Inflammation may also mediate pain in OA. In a recent meta-analysis, it was concluded that subjects with OA have modestly higher circulating CRP levels than controls and that there is great variation in the observed associations between different studies [167]. Circulating CRP levels appeared to be associated more with symptoms than radiographic OA changes [167]. Moreover, synovitis is associated with symptoms including pain [168]. The fact that intra-articular corticosteroids supplied to osteoarthritic joints lead to a rapid reduction in joint pain further implicates inflammation as an important mediator of pain in OA [169]. Interestingly, this effect may be related to a reduction in synovial 35 inflammation [169]. It has, however, not been demonstrated that, by inhibiting knee joint inflammation, corticosteroids are able to reduce cartilage degradation. In a randomised controlled trial, investigating intra-articular hyaluronan treatment and intra-articular hyaluronan + corticosteroid treatment, no significant MRI progression of OA was observed in either study group during the one-year course of the study [170]. Prostaglandins may contribute to sustained joint inflammation and pain. As proof of this, subjects waiting for total knee replacement displayed a dose-responsive decrease in knee synovial fluid concentrations of TNF-α, vascular endothelial growth factor and IL-6 after two weeks of non-steroidal anti-inflammatory drug treatment [171]. Pain and knee function improvements were also observed. Molecules (intact or cleavage products) of cartilage ECM or yielded from chondrocytes are able to activate toll-like receptors and complement and thereby stimulate inflammation. It has been suggested that the inflammation associated with OA is mediated primarily through this mechanism [74, 102]. In subjects with OA who undergo total knee replacement, the symptoms are reduced after the operation, which could be related to the stopped release of cartilage molecules into the synovial fluid, leading to a reduced degree of synovial inflammation subsequent to the operation [74]. However, subjects with higher synovial fluid concentrations of inflammatory markers at the time of total knee replacement experience fewer improvements in pain outcomes following surgery, underpinning the importance of pathological hemostasis in joint tissues other than cartilage for the clinical symptoms associated with OA (for example, synovitis) [172]. Inflammation and post-traumatic knee OA The trauma inflicted on joint tissues at the time of an acute knee injury initiates an immune response. This response may be exaggerated by bleeding into the joint and the degree of acute hemarthrosis may be important for both acute and chronic cartilage degradation by activating inflammatory pathways [173]. Typically, acute tissue injury leads to the release of damage-associated molecular patterns (DAMPs). These molecules, intact or proteolytically processed ECM molecules like biglycan, tenacin-C and hyaluronic acid fragments, and cell-associated molecules, such as high-mobility group box 1 (HMGB1) and uric acid are able to activate immune cells by binding to pattern recognition receptors, including toll like receptors [174-176]. In response to this activation, the immune cells release a variety of different cytokines and chemokines that notify other cells, including macrophages and neutrophils, of ongoing tissue injury [177, 178]. In the acute phase of knee injury, these events can be monitored by analysing the synovial fluid. Rapid increases in synovial fluid concentrations of pro-inflammatory 36 cytokines and proteases such as elastase and MMP-3 have been observed [153, 179, 180]. At a later stage, T-cells that have been recruited to the site of injury, together with macrophages, may induce a state of chronic inflammation, depending on the present cytokine environment [178]. These courses of events after acute knee injury have not been extensively studied. However, clinical joint effusion and investigations of synovial fluid from acutely knee-injured subjects suggest an initial hyper-inflammatory state [146, 179-181]. Importantly, these events are controlled by anti-inflammatory cytokines and protease inhibitors which may maintain homeostasis during the pro-inflammatory stage and thus reduce the proteolytic activity in cartilage [166]. The fact that both IL-1Ra and the protease inhibitor, tissue inhibitor of matrix metalloprotease (TIMP)-1 are increased in the synovial fluid after acute knee injury indicates that this could be the case [179, 180, 182]. Underpinning the importance of inflammation in post-traumatic OA development, injections of corticosteroids into the joint of ACL-transected dogs during surgery and at different time points after surgery led to reduced osteophyte size and reduced histological severity of cartilage lesions [183]. IL-1ra administered intra articularly to subjects with recent ACL injury, furthermore, led to a reduction in pain and knee functional limitations, but it is not known whether such treatment can inhibit OA progression after ACL injury [184

Centre National de Rugby à Marcoussis Thèse présentée et soutenue au Centre National de Rugby à Marcoussis, le 25.11.2016 Composition du Jury : M. Guével, Arnaud Professeur des Universités, Université de Nantes Président M. Morin, Jean-Benoît Professeur des Universités, Université de Nice-Sophia Antipolis Rapporteur M. Perrey, Stéphane Professeur des Universités, Université de Montpellier Rapporteur M. Uhlrich, Gilles Maître de Conférences, Université de Paris Sud Examinateur Mme. Hanon, Christine Chercheur, HDR, INSEP Directrice de thèse Mme. Thomas, Claire Chercheur, HDR, INSEP Co-directrice de thèse M. Piscione, Julien Docteur, Fédération Française de Rugby Invité Université Paris-Saclay Espace Technologique / Immeuble Discovery Route de l’Orme aux Merisiers RD 128 / 91190 Saint-Aubin, France Résumé de la thèse Titre : Analyse des variables physiques, métaboliques et contextuelles de la performance sportive : Le cas du Rugby à 7, nouvelle discipline olympique Mots clés : GPS, lactate, statut acido-basique, répétitions d’efforts Ce travail de thèse s’inscrit dans le cadre de travaux menés en sciences du sport. Basé sur l’exploration des caractéristiques physiques et physiologiques, les performances techniques et physiques des joueurs de l’équipe de France de Rugby à 7, ont été étudiées au travers de l’analyse de tournois internationaux. Dans une première étude, nous avons observé l’impact de variables contextuelles sur les performances physiques et techniques des joueurs en match. Les résultats démontrent que le niveau de l'adversaire ainsi que le résultat du match influencent l’activité des joueurs. Ces derniers sont susceptibles de réaliser de meilleures performances physiques au cours de match dont l’issue est favorable. En effet, les joueurs augmentent la distance totale parcourue dans un match contre un adversaire plus faible. Pour la première fois en Rugby à 7, nous avons montré que les performances techniques sont elles aussi influencées lorsque les joueurs de l’équipe de France jouaient contre une équipe plus forte. En effet, nous avons observé des diminutions du nombre de passes et de situations où les joueurs sont porteurs de balle. Au travers d’une approche physiologique, une deuxième étude a appréhendé les réponses métaboliques individuelles des joueurs de l’équipe de France durant un tournoi international. Les résultats ont montré des relations significatives entre les concentrations de lactate et les pics d’activité enregistrés dans les trois dernières minutes de jeu, ce qui suggère que la capacité à fournir de l'énergie via la voie de la glycolyse est une exigence fondamentale dans cette discipline. L'équilibre acido-basique modifié de façon significative en fin de match, indique que les joueurs doivent être capables de tolérer un niveau important d'acidose due à une forte sollicitation énergétique lors des matchs internationaux. Enfin, notre dernière étude s’est centrée sur les actions de haute intensité effectuées en match. Ces derniers résultats de recherche ont permis de démontrer qu’un joueur réalise en moyenne ~26 actions de haute intensité par match. De plus et pour la première fois dans cette discipline, nous avons montré qu’environ 4 séquences de répétitions d’actions de haute intensité sont comptabilisées en match, dont la durée moyenne est d’environ 40 secondes et comprennent des temps de récupérations inférieurs à 9 secondes. Ainsi, le Rugby à 7 peut être considéré comme un sport collectif de répétitions d’efforts intenses. Pour conclure alors, ces travaux de thèse vont permettre aux entraîneurs et préparateurs physiques de Rugby à 7, de pouvoir s’inspirer de nos résultats pour planifier et mettre en œuvre des entraînements spécifiques aux exigences du Rugby à 7. Université Paris-Saclay Espace Technologique / Immeuble Discovery Route de l’Orme aux Merisiers RD 128 / 91190 Saint-Aubin, France Thesis abstract Title: Analysis of the physical, metabolic and contextual variables of the sports performance: the case of the Rugby Sevens, new Olympic sport Keywords: GPS, lactate, acid-base balance, repeated high intensity efforts Our thesis research fits within the framework of sport science. Based on the exploration of physical and physiological characteristics, technical and physical performance achieved by the French Rugby 7’s team, were studied through the analysis of international tournaments. In the first study, we observe the impact of contextual variables on the physical and technical performance of players during a Rugby 7’s game. The results demonstrate that the level of the opponent and the match result influence the activity of players. Players are likely to perform better physically during a game for which the outcome is favorable. They increase the total distance run in a game against a weaker opponent. For the first time in Rugby 7’s, we were able to show that technical performance is also affected whilst playing against a stronger opponent as there is a decrease in the number of passes and the number of situations where players are ball carriers. Through a physiological approach, the second study focuses on the individual metabolic responses of players during an international Rugby 7’s tournament. The results show a significant relationship between lactate concentrations and peaks activity recorded in the last three minutes of play, suggesting the ability to provide energy via the glycolytic pathway as a fundamental requirement in this sport. Also, the acid-base balance significantly changes towards the end of a game showing that Rugby 7’s players must be able to tolerate a high level of acidosis because the high amount of energy needed for games at an international level. Finally, our last study focuses on high intensity actions done during a Rugby 7’s game. The results show that a player does on average ~26 high intensity actions per game. In addition and for the first time in this sport, we show that approximately 4 sequences of repeated high intensity actions are recorded in a game, the average duration is 40 seconds and includes a time of recovery of under 9 seconds. Thus, Rugby 7’s may be considered as a team sport of repeated high intensity actions. To conclude, this thesis will allow Rugby 7’s coaches and fitness coaches, to better plan and prepare specific trainings that would be adapted to Rugby 7’s. 4 Remerciements A l’issue de la rédaction de ces travaux de recherche, je suis maintenant convaincu qu’une thèse est loin d’être un travail solitaire. En effet, je n’aurais jamais pu réaliser ce doctorat sans le soutien d’un grand nombre de personnes qui m’ont permis de mener à bien l’ensemble de ces recherches. Je vais donc faire en sorte de n’oublier personne… En premier lieu, je tiens à remercier mes directrices de thèse, Claire Thomas-Junius et Christine Hanon, pour la confiance qu’elles m’ont accordée pendant ces quatre années. Toujours de bons conseils, elles ont su m’orienter et me guider. De la même façon, c’est aussi à Julien Piscione, directeur de la performance de la Fédération Française de Rugby, à qui j’ai envie de dire un grand merci. Ton exemplarité au quotidien m’a inspiré, et sans toi, ces travaux ne ressembleraient pas à ce qu’ils sont aujourd’hui…alors merci ! Je souhaite aussi exprimer ma gratitude envers un collègue de travail, un confident, un ami. Mathieu Lacome, sans ton aide par ta présence, tes mails, tes messages, tes appels…deux ou trois années de plus ne m’auraient pas suffi pour clôturer ces travaux, donc merci à toi aussi. Je tiens également à remercier mon jury de thèse : Messieurs Arnaud Guével, Stéphane Perrey, Jean-Benoît Morin et Gilles Uhlrich, qui ont répondu présent pour évaluer ce travail. Merci à vous pour l’intérêt porté à mes recherches. J’exprime ma gratitude envers la Fédération Française de Rugby (à Pierre Camou et Didier Retière, aux entraîneurs et joueurs de l’équipe de France de Rugby à 7, comme à tous les salariés que j’ai côtoyé) ainsi qu’aux membres du laboratoire de l’INSEP, qui m’ont accompagné et soutenu. Un merci particulier à David Courteix et les joueuses de l’équipe de France de Rugby à 7, qui parfois ont subi la proximité entre mes recherches et le terrain. Ces remerciements seraient incomplets si je n’en adressais pas à mes compagnons de galère (Laurie-Anne et Rémi), à mes collègues préparateurs physiques (Alex(s), Bertrand et Julien(s)) et à mes collègues de travail (Danielle, Germain, Florent et Lionel). Leur soutien, chacun à leur façon, était sans faille. Enfin, mille mercis à ma famille et mes amis qui, avec cette question récurrente, « quand est-ce que tu soutiens cette thèse ? », bien qu’angoissante en période (fréquente) de doutes, m’ont permis de ne jamais lâcher. A mon papa… 5 TABLE DES MATIERES LISTE DES ABREVIATIONS ........................................................................ 10 LISTE DES TABLEAUX ................................................................................. 11 LISTE DES FIGURES...................................................................................... 13 LISTE DES IMAGES ....................................................................................... 14 VALORISATION DU TRAVAIL DE THESE .............................................. 15 LE RUGBY A 7 PAR DAVID COURTEIX ................................................... 17 I. AVANT-PROPOS ...............................................................18 1. Historique ................................................................................................. 19 2. Règlement et organisation du Rugby à 7 ................................................. 20 3. Engouement pour le Rugby à 7 ................................................................ 20 4. Collaborations pour cette thèse ................................................................ 21 5. Enjeux et plan de cette thèse .................................................................... 22 6. Aboutissants de cette thèse....................................................................... 23 6 II. REVUE DE LITTERATURE.............................................24 Chapitre 1. Méthode d’analyse de la performance en sport collectif…….. ..................................................................................... 25 1. Les différents outils d’analyse de la performance.................................... 25 2. La validité et la reproductibilité des données GPS .................................. 27 3. Les méthodes d’analyses des données GPS ............................................. 29 4. L’analyse notationnelle ............................................................................ 33 a. Les phases statiques.............................................................................. 34 b. Les actions de jeu (offensives et défensives)........................................ 35 Méthode d’analyse de la performance en sport collectif : l’essentiel ........ 36 Chapitre 2. Le Rugby à 7 et ses spécificités.................................. 37 1. Les exigences techniques en Rugby à 7 ................................................... 37 2. L’impact des variables contextuelles en Rugby à 7 ................................. 40 3. L’impact du poste des joueurs (avant/arrière).......................................... 42 a. Les avants ............................................................................................. 42 b. Les arrières............................................................................................ 42 4. Le statut des joueurs................................................................................. 45 Le Rugby à 7 et ses spécificités : l’essentiel .................................................. 46 Chapitre 3. Les contraintes physiques et physiologiques en Rugby à 7…… ................................................................................... 47 1. Les caractéristiques physiques des joueurs de Rugby à 7 ........................ 47 a. Morphologie des joueurs ...................................................................... 47 b. Qualité aérobie des joueurs................................................................... 48 c. Qualité de puissance des joueurs .......................................................... 49 d. Qualité de vitesse des joueurs............................................................... 50 2. Les exigences physiques en match de Rugby à 7..................................... 52 a. Analyse des performances physiques en match.................................... 52 b. Observation des répétitions d’actions de haute intensité en match....... 53 3. Les conséquences sur le plan énergétique................................................ 57 a. La première source d’énergie : la phosphocréatine .............................. 57 b. Le métabolisme du lactate .................................................................... 60 Les contraintes physiques et physiologiques en Rugby à 7 : l’essentiel .... 64 7 III. OBJECTIFS DE THESE ....................................................65 IV. METHODOLOGIE.............................................................69 1. La population............................................................................................ 70 2. Les évaluations physiques........................................................................ 70 a. Anthropométrie..................................................................................... 70 b. Détermination de la vitesse maximale aérobie (VMA) ........................ 70 c. Détermination de la consommation maximale d’oxygène (VO2max).... 70 d. Détermination de la vitesse maximale (Vmax)....................................... 71 e. Détermination du statut acido-basique sanguin .................................... 72 f. Détermination des capacités de force musculaires des membres inférieurs et supérieurs.......................................................................... 72 g. Détermination de la puissance des membres inférieurs........................ 73 3. Les matchs................................................................................................ 73 4. L’analyse des performances physiques.................................................... 74 a. Le système GPS .................................................................................... 74 b. Individualisation des catégories de course............................................ 75 c. Analyse vidéo ....................................................................................... 75 d. Analyse des efforts de haute intensité................................................... 75 5. Les prélèvements sanguins en match ....................................................... 76 6. Les analyses statistiques........................................................................... 77 V. CONTRIBUTION PERSONNELLE ................................80 Chapitre 1. Préambule - Description des caractéristiques physiques et physiologiques des joueurs de l’équipe de France de Rugby à 7……. .................................................................................. 81 8 Chapitre 2. ETUDE 1 : Impact des variables contextuelles sur la performance en Rugby à 7 ............................................................... 91 1. Objectif de l’étude 1................................................................................. 92 2. Le point de vue d’un joueur professionnel............................................... 92 3. Méthodologie ........................................................................................... 93 a. Population ............................................................................................. 93 b. Procédures expérimentales.................................................................... 93 c. Synthèse des tests utilisés..................................................................... 93 4. Les résultats principaux............................................................................ 94 a. Relation entre le résultat du match et les performances physiques et techniques ............................................................................................. 94 b. Influence du niveau de l’adversaire sur les performances physiques et techniques ............................................................................................. 96 c. Analyse par Cluster............................................................................... 98 5. Discussion et Conclusion ......................................................................... 99 L’impact des variables contextuelles en Rugby à 7 : l’essentiel ............... 102 Chapitre 3. ETUDE 2 : Analyse des réponses physiologiques en Rugby à 7….. ................................................................................... 103 1. Objectif de l’étude 2............................................................................... 104 2. Le point de vue d’un joueur professionnel............................................. 104 3. Méthodologie ......................................................................................... 105 a. Population ........................................................................................... 105 b. Procédures expérimentales.................................................................. 105 c. Synthèse des tests utilisés................................................................... 105 4. Les résultats principaux.......................................................................... 106 a. Description des performances physiques............................................ 106 b. Description des réponses physiologiques ........................................... 108 c. Relation entre les performances physiques et les réponses physiologiques.................................................................................... 110 5. Discussion et Conclusion ....................................................................... 112 Les réponses physiologiques en Rugby à 7 : l’essentiel............................. 117 9 Chapitre 4. ETUDE 3 : Analyse des répétitions d’actions de haute intensité en match international de Rugby à 7 ................. 118 1. Objectif de l’étude 3............................................................................... 119 2. Le point de vue d’un joueur professionnel............................................. 120 3. Méthodologie ......................................................................................... 120 a. Population ........................................................................................... 120 b. Procédures expérimentales.................................................................. 120 c. Synthèse des tests utilisés................................................................... 122 4. Les résultats principaux.......................................................................... 122 5. Discussion et Conclusion ....................................................................... 136 La performance en Rugby à 7 : l’essentiel ................................................. 141 VI. DISCUSSION GENERALE.............................................142 1. Seuils de vitesse de course et entraînement ........................................... 143 2. Séquences de répétitions d’actions de haute intensité et entraînement.. 148 3. Entraînement et variables contextuelles : une notion incontournable ? . 151 4. Efforts intenses, réponses métaboliques et récupération........................ 152 VII. PERSPECTIVES...............................................................155 VIII. CONCLUSION..................................................................157 IX. BIBLIOGRAPHIE............................................................159 X. ANNEXES ..........................................................................172 10 Liste des abréviations [x] : Concentration ADP : Adénosine-diphosphate AMP : Adénosine-monophosphate ASR : “Anaerobic Speed Reserve“ ATP : Adénosine-Triphosphate CK : Créatine kinase CO2 : Dioxyde de carbone DEXA : “Dual Energy X-ray Absorptiometry” DT : Distance Totale FFR : Fédération Française de Rugby GLUT : Transporteur de glucose GPS : “Global Positioning Systems“ H+ : Ion hydrogène HCO3 - : Ion hydrogénocarbonate INSEP : Institut National du Sport de l’Expertise et de la Performance IRB : “International Rugby Board“ Joueur WM : match complet Joueur R : remplacé Joueur S : remplaçant La : Lactate MG : Masse Grasse MT1 : Première mi-temps MT2 : Deuxième mi-temps NADH : Nicotinamide-adénine-dinucléotide NaHCO3 : Bicarbonate de sodium NR : Non Renseigné PaCO2 : Pression artérielle en CO2 PCr : Phosphocréatine Pi : Phosphate inorganique RAA : habileté à répéter des accélérations RAS : répétition de séquences d’accélération RHIE : “Repeated High Intensity Effort“ RSE : répétition d’exercices de sprint RSS : répétition de séquences de sprint SGLT : “Sodium/Glucose Co-Transporter“ TMA : “Time Motion Analysis“ Vmax : Vitesse maximale VMA : Vitesse maximale aérobie VO2 : Volume d’oxygène consommé VO2max : Volume maximal d’oxygène consommé WR : “World Rugby“ WSS : “World Sevens Series“ 11 Liste des tableaux Tableau 1 : Analyse de la performance en compétition internationale de Rugby à 7. Quantification des indicateurs de performance par match et par équipe. ................................ 38 Tableau 2 : Comparaison des performances de joueurs de Rugby à 7 en fonction des postes : avant ou arrière......................................................................................................................... 44 Tableau 3 : Comparaison des profils de joueurs de Rugby à 7 en fonction des postes .......... 47 Tableau 4 : L’analyse des performances physiques via l’outil GPS, en compétition de Rugby à 7 ............................................................................................................................................. 52 Tableau 5 : Comparaison entre mi-temps, de l’activité de répétition de courses de haute intensité réalisée par un joueur, en match international de Rugby à 7. Extrait de “Repeatedhigh intensity running activity and internal training load of elite rugby sevens players during international matches a comparison between halves” Suarez-Arrones et coll.2015................ 55 Tableau 6 : Organisation et résultats de l’équipe de France de Rugby à 7 masculine, au tournoi Européen de Lyon 2013............................................................................................... 74 Tableau 7 : Caractéristiques anthropométriques des joueurs de l’équipe de France de Rugby à 7 au cours de la saison 2013-2014 ........................................................................................... 82 Tableau 8 : Performances physiques aérobies des joueurs de l’équipe de France de Rugby à 7 au cours de la saison 2013-2014 .............................................................................................. 83 Tableau 9 : Profil force-vitesse des joueurs de l’équipe de France de Rugby à 7 au cours de la saison 2013-2014, confrontés à ceux des joueurs de rugby à XIII et à XV (données extraites de Cross et coll. 2015).............................................................................................................. 84 Tableau 10 : Performances physiques de force et de puissance des joueurs de l’équipe de France de Rugby à 7 au cours de la saison 2013-2014 ............................................................ 87 Tableau 11 : Réponses métaboliques des joueurs de l’équipe de France de Rugby à 7 au cours de la saison 2013-2014, suite à une course en sprint de 300 mètres. ............................. 88 Tableau 12 : Relation entre le résultat du match et les performances physiques et techniques .................................................................................................................................................. 95 Tableau 13 : Influence du niveau de l’adversaire sur les performances physiques et techniques................................................................................................................................. 97 Tableau 14 : Performances physiques des joueurs au cours d’un tournoi de Rugby à 7...... 107 Tableau 15 : Réponses physiologiques des joueurs au cours d’un tournoi de Rugby à 7 .... 109 12 Tableau 16 : Relation entre les performances physiques réalisées sur les trois dernières minutes de jeu et les variations du pH, [HCO3 - ] et [La] au cours d’un tournoi de Rugby à 7111 Tableau 17 : Distribution des actions de haute intensité par joueur et par match, en Rugby à 7. Différences en fonction des postes..................................................................................... 124 Tableau 18 : Types de séquence de répétitions d’actions de haute intensité (RHIE), selon les postes, pour les joueurs ayant joué un match complet en Rugby à 7. .................................... 128 Tableau 19 : Comparaison de la distribution des actions de haute intensité par joueur et par mi-temps (MT), en Rugby à 7. Différences en fonction des postes....................................... 131 Tableau 20 : Comparaison de la distribution des séquences de répétitions d’actions de haute intensité (RHIE) par joueur et par mi-temps, en Rugby à 7. Différences en fonction des postes...................................................................................................................................... 134 Tableau 21 : Présentation de seuils absolus issus de différentes études en rugby. Extrait de “A comparison of the physiological demands of rugby union match-play when determined by absolute (ABS) or individual (IND) velocity bands in Global Positioning System (GPS) analysis”. Macleod (2016)...................................................................................................... 144 13 Liste des figures Figure 1 : Evolution de 2000 à 2016, du nombre d’études relatives au Rugby à 7 publiées dans des revues internationales................................................................................................ 21 Figure 2 : Déplacement d’un joueur pendant une séquence de jeu de 30 secondes. Découpage de l’allure de course individualisée et vitesses atteintes. ......................................................... 31 Figure 3 : Relation force-vitesse et courbe de puissance de deux sujets (rouge et noir) ........ 49 Figure 4 : Illustration de la navette extracellulaire du lactate (Fibre rapide, Fibre lente)....... 61 Figure 5 : Organisation du « World Sevens Series » masculin, de la saison 2015-2016........ 73 Figure 6 : Différences de profils force-vitesse en fonction des types de rugby pratiqués (7, XIII et XV) selon les postes des joueurs (avant et arrière). ................................................ 86 Figure 7 : Cinétique du pH sanguin, post-300m chez des joueurs de Rugby à 7.................... 88 Figure 8 : Cinétique du bicarbonate sanguin, post-300m chez des joueurs de Rugby à 7...... 89 Figure 9 : Cinétique du lactate sanguin, post-300m chez des joueurs de Rugby à 7 .............. 89 Figure 10 : Dendrogramme représentant la similarité relative des différentes variables en fonction de leur impact sur les performances physiques et techniques des joueurs ................ 98 Figure 11 : Évolution des concentrations de lactate durant un tournoi de Rugby à 7, pour l’ensemble des joueurs........................................................................................................... 110 Figure 12 : Distribution des actions de haute intensité par match, par joueur, en Rugby à 7 ................................................................................................................................................ 123 Figure 13 : Répartition des séquences de répétitions d’actions de haute intensité (RHIE) en fonction du nombre d’actions qu’elles contiennent, par poste et par match. ......................... 126 Figure 14 : Distribution des actions de haute intensité par match et par joueur, au sein d’une séquence de répétitions d’actions de haute intensité (RHIE), en Rugby à 7.......................... 127 Figure 15 : Illustration d’une mi-temps représentative d’un match de Rugby à 7................ 137 Figure 16 : Exemple type de l’analyse GPS d’un match d’un joueur de Rugby à 7, avec seuil absolu et seuil individualisé ................................................................................................... 146 Figure 17 : Représentation des zones de vitesse anaérobie de réserve, de deux sujets aux vitesses maximales différentes mais avec des VO2max identiques.......................................... 147 Figure 18 : Exemple infographique des stratégies de récupération entre deux matchs de Rugby à 7. Extrait de Couderc dans Schuster et coll. (2016) en préparation......................... 154 14 Liste des images Image 1 : Schéma d’usage de l’outil d’analyse : GPS Digital Simulation.............................. 28 Image 2 : Capture d’écran du logiciel Dartfish ....................................................................... 33 Image 3 : Illustration de la méthode de prélèvement sanguin ................................................. 76 15 Valorisation du travail de thèse Ce travail de thèse a fait l’objet des publications et communications suivantes Publications en relecture ou acceptées dans des revues internationales à comité de lecture x COUDERC.A, THOMAS.C, LACOME.M, PISCIONE.J, ROBINEAU.J, DELFOURPEYRETHON.R, BORNE.R, HANON.C (2016). Movement Patterns and Metabolic Responses During an International Rugby Sevens Tournament. International Journal of Sports Physiology and Performance. Acceptée. http://dx.doi.org/10.1123/ijspp.2016-0313 (Annexe 1) x COUDERC.A, PISCIONE.J, ROBINEAU.J, IGARZA.G, THOMAS.C, HANON.C, LACOME.M (2016). Impact of Contextual Variables on Running and Skill-Related Performance in International Rugby Sevens. PLOS One. Soumise en Septembre 2016 (Annexe 2) Collaborations pour des publications en relecture ou acceptées dans des revues internationales à comité de lecture x MARRIER.B, LE MEUR.Y, ROBINEAU.J, LACOME.M, COUDERC.A, HAUSSWIRTH.C, PISCIONE.J, MORIN.JB (2016). Quantifying Neuromuscular Fatigue Induced by an Intense Training Session in Rugby Sevens. International Journal of Sports Physiology and Performance. Acceptée. http://dx.doi.org/10.1123/ijspp.2016-0030 (Annexe 3) x SCHUSTER.J, HOWELLS.D, ROBINEAU.J, COUDERC.A, NATERA.A, LUMLEY.N, GABBETT.T, WINKELMAN.N, McMASTER.T (2016). Physical preparation recommendations for elite rugby sevens performance. International Journal of Sports Physiology and Performance. Soumise en Novembre 2016 (Annexe 4) 16 Ouvrages x COUDERC.A, THOMAS.C, PISCIONE.J, HANON.C. Exigences physiques et réponses métaboliques au cours d’un tournoi international de Rugby à 7. Pathologies du rugbyman. SAURAMPS Médical. Biarritz, France, Octobre 2014. x VIEU.C, BOUCHE.R, CAMPARGUE.B, COUDERC.A, COZZOLINO.C, FREY.A, GRANVORKA.F, MAURELLI.O, PAULY.O, RICARD.M, STEINER.F, GENDRE.P. Développement de l'intelligence de l'épaule. Edition INSEP, Parution prévue : Décembre 2016. Congrès nationaux et internationaux x COUDERC.A. Exigences physiques et réponses métaboliques au cours d’un tournoi international de Rugby à 7. ACAPS. Grenoble, France, Octobre 2013. x COUDERC.A, ROBINEAU.J. Exigences physiques et réponses physiologiques en Rugby à 7. 14ème Congrès National de l’Association des Kinés Rugby, Paris, France, Février 2015 x COUDERC.A, THOMAS.C, LACOME.M, PISCIONE.J, ROBINEAU.J, DELFOURPEYRETHON.R, BORNE.R, HANON.C. Movement patterns and metabolic responses during an international tournament of Rugby Sevens. E-Poster, European Congress of Sport Science. Malmö, Suède, Juin 2015. Conférences x COUDERC.A. Sport et Jeunes Sportifs. Sport Santé - CROS Languedoc-Roussillon. Gruissan, France, Novembre 2014. x COUDERC.A. Journée Sport Santé Préparation Physique. Université Paris Est-Créteil & Département du Val de Marne, France, Avril 2016. 17 Le Rugby à 7 par David COURTEIX Les oriflammes s’agitent, l’atmosphère a cette dimension électrique qui donne aux énergies la saveur des grands plats, le public gronde de plaisir ! Un coup de sifflet strident à peine perceptible dans ce brouhaha agréablement soûlant, signe le début d’une courte pause ! Il y a un peu plus de 7 minutes que les étreintes brutales et furtives s’enchaînent, que les accélérations et les changements d’orientation de course se succèdent, qu’il faut passer du ventre à terre à la station debout puis inversement. Avec une agilité de chat, un esprit de gladiateur et le sang-froid d’un pilote de ligne, il faut rester connecté, jouer en équipe, toujours et sans relâche ! Bienvenue dans le monde excitant et extrême du Rugby à 7, désormais olympique, c’est à peine la mi-temps de la sixième et dernière rencontre du weekend. Une armée d’ombres s’avance, les visages sont blafards, les yeux délavés, rougis par l’effort, dessinent des orbites exagérément profondes au fond desquelles les pupilles dilatées renforcent le sentiment hagard que donne la petite troupe, les mâchoires sont tendues, les souffles sont asthmatiques… Les démarches déterminées quoique robotiques tranchent presque avec le tableau de ces corps engourdis par les effluves de l’acide lactique. L’acidose, ou plutôt l’aptitude à repousser puis à vivre au seuil de tolérance de ce shoot indispensable à la performance dans ce sport aux efforts intenses, aléatoires et tellement variés, est l’une des clés de l’entraînement des athlètes quel que soit leur profil. Les travaux d’Anthony Couderc autour de ce thème, tant dans l’attention portée à l’impact de certaines variables contextuelles, qu’aux détails des différentes réponses métaboliques ou à la précision qu’il porte à l’analyse de l’enchaînement des tâches de haute intensité, sont un véritable apport à la démarche d’entraînement de ces athlètes hors normes, que sont les joueuses et joueurs de rugby à 7 de haut niveau. Les incidences concrètes qu’auront les conclusions de ces recherches à l’avenir sur le développement de nouvelles formes de méthodologies d’entraînement seront je le pense déterminantes. Entraîneur de l’équipe de France de Rugby à 7 féminine depuis 2010 18 I. AVANT-PROPOS 19 1. Historique Le Rugby à 7, sport collectif dérivé du Rugby à XV, provient de l’imagination de deux bouchers écossais. À l’occasion d’un tournoi organisé aux bénéfices de leur club en 1883, le « Sevens » naît sur le Greenyards du Melrose Rugby Football Club. Certains effectifs étant incomplets et de façon à offrir du spectacle, les bouchers décident de faire jouer les matchs en quinze minutes et de diminuer la taille des équipes à sept joueurs. Ce n’est presque que cent ans plus tard, au Murrayfield Stadium en 1973, que l’International Rugby Board (IRB) (aujourd’hui « World Rugby » (WR)) organise un tournoi international officiel lors de la célébration du centenaire de la Fédération Écossaise de Rugby à XV. S’affrontent alors huit nations où l’Angleterre, pays vainqueur, est saluée par la presse internationale comme première équipe championne du monde de Rugby à 7. C’est le succès du tournoi d’Hong-Kong en 1976 qui va entraîner la naissance de plusieurs tournois aux quatre coins du monde. La première coupe du monde s’organise en 1993 dans le berceau du Rugby à 7, à Edimbourg en Écosse. S’y opposent vingt-quatre équipes nationales où l’Angleterre l’emporte face à l’Australie (21-17) et où la France se classe à la dixième place. Par la suite, l’IRB organise en 1999 un circuit mondial, le « World Sevens Series » (WSS), qui comporte dix tournois, s’étendant sur l’ensemble d’une saison et qui couronne, au cumul de points, la meilleure nation. Le Rugby à 7 féminin n’arrive que plus tard sur la scène internationale. Le premier circuit mondial est organisé durant la saison 2011/2012 et comprend seulement trois tournois : Dubaï, Hong-Kong et Londres. Aujourd’hui 6 tournois sont organisés à l’occasion du « World Women’s Sevens Series ». De l’Afrique du Sud en passant par le Kenya, l’Argentine, les Etats-Unis, le Canada ou encore les Samoa et même jusqu’en Russie, le Rugby à 7 se joue au féminin et au masculin, partout dans le monde. L’universalité de cette discipline entraîne le Comité International Olympique (CIO) à annoncer le 9 Octobre 2009, l’intégration du Rugby à 7 (féminin et masculin) parmi les sports présents aux Jeux Olympiques d’été de 2016, à Rio de Janeiro, marquant ainsi un tournant dans le développement et la promotion de ce sport et ce sur tous les continents. Au vu de l’intérêt mondial grandissant pour le Rugby à 7 et en conséquence de la concurrence internationale de plus en plus relevée, la Fédération Française de Rugby (FFR) crée en 2010 un Département Olympique au sein de sa direction sportive et professionnalise ses joueurs et joueuses des équipes de France de Rugby à 7, afin que ces derniers se 20 spécialisent dans cette discipline. En remportant chacune en 2015 leur Championnat d’Europe, les équipes de France à la fois masculine et féminine se sont qualifiées pour le premier tournoi Olympique de Rugby à 7, où ils finirent respectivement à la septième et sixième place. 2. Règlement et organisation du Rugby à 7 Ce format « Sevens » calque son règlement sur le Rugby à XV mais s’en distingue sur différents points. Sur le plan organisationnel, c’est sous forme de tournoi que ce Rugby se joue avec six matchs en deux jours par équipe. Les matchs se jouent en deux mi-temps de sept minutes (sauf les finales en deux fois dix minutes), opposant sept joueurs de part et d’autre avec cinq remplacements possibles sur un terrain de mêmes dimensions que celui du Rugby à XV. Sur le plan règlementaire, on peut noter trois grandes différences, 1) les mêlées se disputent à trois joueurs ; 2) l’équipe qui marque engage ensuite ; 3) les pénalités et transformations sont toutes jouées en « drop goal » (le ballon est frappé juste après être tombé au sol). Sur le plan organisationnel, les joueurs sont répartis comme suit : trois avants avec deux piliers et un talonneur, et quatre arrières avec un demi de mêlée, un demi d'ouverture, un centre et un ailier/arrière. Les postes 1, 2 et 3 correspondent respectivement au pilier gauche, au talonneur et au pilier droit qui disputent les mêlées et les touches (ici à trois). Le poste 4 est celui du demi de mêlée qui anime le jeu et qui effectue le plus souvent les touches. Le poste 5 est l’ouvreur : véritable chef d’attaque, chargé souvent du jeu au pied. Les postes 6 (centre) et 7 (ailier) complètent la ligne d’attaque. 3. Engouement pour le Rugby à 7 L’avènement du Rugby à 7 féminin et masculin à l’olympisme engendre une popularité en pleine croissance à différents stades : des quinzistes qui apprécient cette pratique dont le jeu est la sève ; un public qui se déplace pour profiter du côté spectaculaire de cette discipline (l’étape d’Hong-Kong enregistre les plus grosses affluences : 120 000 personnes sur trois jours de compétition en 2014) ; des médias pour couvrir les événements (l’étape de Dubaï de 2014 a pu être suivie par 230 000 000 de foyers répartis sur 140 pays). 21 0 2 4 6 8 10 12 14 16 18 20 2000 2002 2004 2006 2008 2010 2012 2014 2016 Le monde scientifique n'est pas épargné par ce phénomène comme le montre la croissance exponentielle du nombre de publications se consacrant à ce sport depuis l’annonce de son intégration au programme olympique en 2009 (Figure 1). Figure 1 : Evolution de 2000 à 2016, du nombre d’études relatives au Rugby à 7 publiées dans des revues internationales 4. Collaborations pour cette thèse Ce travail de thèse a été réalisé au sein du laboratoire « Sport Expertise et Performance » Équipe d’Accueil 7370, de l’Institut National du Sport de l’Expertise et de la Performance (INSEP), en partenariat avec la Fédération Française de Rugby, avec pour objectif d’optimiser la préparation aux Jeux Olympiques. Essentiellement centrés sur la pratique masculine, différents travaux ont été réalisés pour accompagner cette équipe dans sa préparation. La réalisation de cette thèse a donc été le fruit d’un travail collaboratif initié par la cellule recherche de la FFR au travers de l’expertise de Lacome.M et Piscione.J ainsi que par mes directrices de thèse, Mme Hanon.C et Mme Thomas-Junius.C. Nombre Année 22 5. Enjeux et plan de cette thèse Les enjeux de ce travail de thèse, initié en 2013, étaient multiples. Tout d’abord, comme premier point d’ancrage et à la lumière de multiples travaux, la prise en compte du phénomène complexe que représente un sport collectif paraissait essentielle ; dans ce cadre, la première étude s’est attachée à analyser l’impact du contexte sur les performances techniques et physiques des joueurs. Ensuite, sur la base d’une approche physiologique, observer les réponses métaboliques des joueurs semblait être une étape fondamentale de nos recherches. En Rugby à 7, la littérature sur le sujet étant peu fournie, il était souhaitable d’investiguer aussi cette composante, clé de la performance. À court terme, ceci nous permettrait de parfaire la préparation des joueurs professionnels pour les Jeux Olympiques ; dans un second temps et à plus long terme, ces observations pourraient servir à la détection de futurs talents puis au développement de programmes d’entraînement spécifiques au Rugby à 7. Enfin, analyser les exigences techniques et physiques de cette discipline en compétition internationale était incontournable. Examiner les types d’enchaînement d’efforts intenses en match nous paraissait fondamental dans le but de proposer de nouvelles prescriptions d’entraînement spécifiques pour le Rugby à 7. Afin de répondre à ces problématiques, ce manuscrit se présente alors en huit parties. La première partie de ce travail de thèse reposera sur une revue de littérature des différentes méthodes d’analyse de la performance en sport collectif, des différents travaux relatifs à l’analyse de la performance en Rugby à 7, puis des exigences physiques et des réponses physiologiques associées à cette discipline. La seconde partie présentera en détail les objectifs de cette thèse. La troisième, quant à elle, se centrera sur l’explication des méthodologies spécifiques employées au cours des différentes études de recherche. Une quatrième aura en guise de préambule, la description des caractéristiques physiques et physiologiques des joueurs de l’équipe de France ; cette partie permettra ensuite d’expliciter quelle aura été notre contribution personnelle à l’avancement des connaissances scientifiques dans le domaine de l’analyse du Rugby à 7 et ce, au travers de trois études. Enfin, les cinquième, sixième et septième parties de ce manuscrit serviront de support pour discuter, envisager les perspectives et applications pratiques qui se dégageront de ce travail de thèse puis conclure. 23 6. Aboutissants de cette thèse Les résultats originaux de ce travail de thèse peuvent avoir plusieurs applications directes concernant l’analyse de la performance en Rugby à 7, le développement de programmes d’entraînement spécifiques à la discipline, jusqu’à la détection de jeunes talents. Les analyses réalisées en compétitions internationales vont permettre d’aboutir à un descriptif fin de la discipline ; d’inspirer les entraîneurs et préparateurs physiques pour créer des séquences spécifiques d’entraînement pour leurs joueurs afin de développer des compétences spécifiques au Rugby à 7. Les entraîneurs pourront prendre en compte certains résultats pour affiner leur stratégie de coaching au cours des matchs. Les préparateurs physiques, eux, pourront orienter leurs joueurs spécifiquement sur différentes modalités de préparation, en fonction des qualités physiques principales à développer. 24 II. REVUE DE LITTERATURE 25 Chapitre 1. Méthode d’analyse de la performance en sport collectif 1. Les différents outils d’analyse de la performance L’analyse de l’activité en sport collectif existe maintenant depuis plus d’un demisiècle. Dans les années 50, Winterbottom (1952) s’est intéressé le premier à l’analyse du football en match. Plus tard dans les années 70, Reilly et Thomas (1976) se sont consacrés à l’optimisation des méthodes d’analyse de la tâche pour les sports collectifs en se basant sur les évolutions de la vidéo. Dans les années 2000, Duthie et coll. (2005) et Deutsch et coll. (2007) utilisent eux, l’outil informatique pour accélérer les analyses à partir de logiciel spécifique d’analyse vidéo (Part Timer V1.1, Australian Sports Commission, Canberra). Pour autant, ces méthodes d’analyse peu coûteuses en matériel, présentent des inconvénients majeurs : elles sont chronophages et ne proposent pas une grande reproductibilité. De fait, ce sont les systèmes semi-automatiques qui se sont développés par la suite. Les plus connus et les plus utilisés actuellement sont les systèmes Amisco (Sport Universal Process, Nice, France) et Prozone (West Yorshire, Angleterre). Ces systèmes s’organisent autour de six à huit caméras installées et calibrées autour du stade, dont la fréquence d’acquisition est de 25 Hz, de façon à suivre sous tous les angles, les déplacements de tous les joueurs en simultané. Les stades et les terrains équipés sont calibrés en hauteur, profondeur et largeur puis transformés en un espace à deux dimensions afin de calculer instantanément la position des joueurs. La nécessité de l’intervention de l’opérateur se justifie lorsque les joueurs se croisent dans les champs des caméras et/ou lorsqu’il y a des regroupements (fréquent en rugby). Ces systèmes semi-automatiques ont été démontrés comme fiables et reproductibles. L’article de Valter et coll. (2006) en fait la démonstration au travers d’une confrontation des données Prozone à celles issues de cellules photoélectriques. Au cours de courses de 60 m (r = 0,999 ; erreur totale 0,05 ; limite d’agrément 0,12) et de sprint sur 15 m (r = 0,970 ; erreur totale 0,23 ; limite d’agrément 0,85), ils mettent en avant de fortes corrélations entre ces données qui assurent la fiabilité des systèmes semi-automatiques. Au-delà de leur caractère onéreux, leur utilisation s’organise exclusivement autour de l’analyse de match. L’intérêt d’analyser les entraînements étant grandissant, alors, c’est l’outil GPS (« Global Positionning System ») qui a été développé et adapté au contexte sportif. 26 D’abord élaboré par le département de la défense du gouvernement des États-Unis pendant la guerre froide, le GPS se compose de trois éléments clés : les satellites spatiaux, les stations de contrôle sur terre et les récepteurs GPS. Le système GPS dispose de vingt-quatre satellites qui tournent autour de la Terre en six trajectoires orbitales, émettant des signaux radio depuis leurs positions en orbite qui s'élèvent à plus de 20 000 kilomètres au-dessus de nos têtes. Les satellites émettent ainsi des signaux couvrant chacun une vaste zone de la surface de la Terre et leurs orbites sont mises en chorégraphie de telle manière que les récepteurs GPS sur Terre reçoivent toujours des signaux d'au moins trois satellites, le nombre dont nous avons besoin pour déterminer une position par simple triangulation. Il existe cinq stations de contrôle : la station principale de Colorado Springs aux Etats-Unis, et quatre stations inhabitées ; l'une se trouve à Hawaï, les trois autres sont dans des endroits lointains, aussi près que possible de l'équateur : l'île de l'Ascension au milieu de l'Atlantique, Kwajalein dans le Pacifique et l'Atoll de Diego Garcia dans l'Océan Indien. Les quatre stations inhabitées reçoivent constamment des données depuis les satellites et les transmettent à la station de contrôle principale qui les corrige et renvoie ensuite ces données corrigées vers les satellites. Les récepteurs GPS captent les signaux des satellites pour déterminer une position. Le principe du système GPS est de mesurer le temps nécessaire à un signal radio émis par une balise sur Terre, pour être réceptionné par un satellite. C’est à partir de cette vitesse de propagation du signal radio qu’il devient possible de calculer la distance entre le satellite et la balise par intégration. Plus il y aura de satellites, plus précise sera la localisation. L’utilisation de cet outil s’est très largement répandue dans le milieu sportif depuis une dizaine d’années dans le but de quantifier/qualifier les déplacements des sportifs. Du football australien aux différentes pratiques du rugby (à XV, à XIII et à 7) en passant par le cricket ou encore le hockey, énormément de disciplines utilisent ce matériel. Sous couvert des « sport-scientists », tous se sont intéressés à cet outil de façon à mieux comprendre leur discipline sportive à l’entraînement et en compétition. Jusqu’en 2010, l’IRB n’autorisait pas le port de GPS en compétition, ce qui limitait leur utilisation exclusive à l’entrainement. Face à l’engouement et aux motivations d’une majorité de nations, l’IRB fini par autoriser le port du GPS en match, sous condition d’importantes démarches administratives à mettre en place (consentement de l’organisateur du tournoi, des joueurs portant les GPS ainsi que de leurs adversaires). 27 2. La validité et la reproductibilité des données GPS Les tests de validité et reproductibilité des données issues des GPS pour l’analyse des sports collectifs ont été multiples ces dernières années (Petersen et coll. 2009, Coutts et coll. 2010, Duffield et coll. 2010, Jennings et coll. 2010, Waldron et coll. 2011, Johnston et coll. 2012, Duncan et coll. 2013). Ces études ont mis en œuvre différents moyens afin de justifier de la qualité des données issues des GPS utilisés. En effet, concernant la validité, les GPS ont souvent été confrontés à d’autres systèmes de mesure dont la validité était déjà prouvée : cellule photoélectrique, radar (50 Hz), jusqu’au système déjà en place pour l’analyse de match comme les systèmes semi-automatiques. Les conclusions soulignent logiquement que plus la fréquence d’échantillonnage des GPS est grande (1, 5 et 10 Hz) meilleure sera la validité des données. En effet, Varley et coll. (2012) ont démontré par exemple qu’un GPS 10 Hz était deux à trois fois plus précis qu’un GPS 5 Hz (coefficient de variation de 3,1 à 11,3%). Récemment, Nagahara et coll. (2016), ont démontré que des GPS 20Hz surestiment la Vmax de seulement 0,1%, alors que des GPS 5Hz vont eux la sous-estimer de -4,8%, comparé à des données radar. Pour les tests de reproductibilité, c’est sur la base de distance à parcourir à différentes allures (marche, footing, course et sprint) incluant des changements de direction, que les systèmes ont été évalués. Les études ont plus de difficultés à s’accorder ici, pour autant, elles soulignent que plus le volume de course augmente, plus la reproductibilité est grande, et qu’inversement, plus l’intensité augmente plus la reproductibilité des données diminue (au cours d’une tâche de marche de 8800 m, le coefficient de variation est de 1,4 à 2.6% alors qu’il passe de 19,7 à 30.0% sur un sprint de 20 m) (Aughey et coll. 2011). Une revue de littérature récente (Malone et coll. 2016), précise qu’il serait intéressant d’élaborer une approche standardisée des données GPS afin de comparer plus facilement les données d’une étude à une autre, pour mieux comprendre les performances des athlètes. Synthèse : Les différents outils d’analyse de la performance . L’analyse des sports collectifs est au départ basée sur l’analyse vidéo. . Les systèmes semi-automatiques s’organisent autour du recueil de données de plusieurs caméras, pour suivre sous plusieurs angles les déplacements des joueurs (fournisseurs principaux : Amisco et Prozone). . Principe du GPS : calcul de la vitesse d’un signal entre une balise et un satellite pour déterminer une position. 28 La FFR, en collaboration avec la marque Digital Simulation (SensorEveryWhere, France), utilisait de 2010 à 2015, des GPS à la fréquence d’acquisition de 8 Hz (16 Hz aujourd’hui), qui permettent le suivi des joueuses et joueurs des différentes équipes de France, à la fois pendant les entraînements mais aussi au cours des matchs internationaux. Ce matériel se compose d’une valise regroupant trente balises GPS, un bloc antennes et un ordinateur à usage exclusif des données (Image 1). Image 1 : Schéma d’usage de l’outil d’analyse : GPS Digital Simulation La validité et la reproductibilité des données issues des GPS utilisés par la FFR, ont été observées en interne au travers des travaux de Peeters et coll. (2016). Ces derniers ont comparé les données issues des GPS avec celles de matériels validés par la littérature comme le système radar et celui des cellules photoélectriques. Ils affirment donc que : (1) une différence trivial existe entre la vitesse obtenue par les GPS et celles des cellules photoélectriques (0,11, ± 0,04 m.s-1 ) avec une erreur typique de mesure de 0,04, ± 0,01 m.s-1 (avec un intervalle de confiance de 90%) ; (2) une faible erreur typique de mesure est à noter d’un GPS à un autre (0,01, ± 0,01 à 0,04, ± 0,04 m.s-1 et 0,5, ± 0,15 à 0,6, ± 0,35% de la marche au sprint, respectivement) ; (3) une différence trivial lors des mesures de vitesse maximale et d’accélérations est aussi à relever, d’un GPS à un autre (0,06, ± 0,03% et 3,1, ± 6.4% respectivement). Ils en concluent donc que la technologie utilisée propose des données valides et reproductibles pour l’analyse en sport collectif. 29 3. Les méthodes d’analyses des données GPS Cummins et coll. (2013) ont eux, publié une revue de littérature se basant sur trentecinq études afin d’analyser le type de données GPS récoltées. Ce travail avait inclus toutes les études comportant des données GPS recueillies dans différentes disciplines : huit en football australien, sept en football, six en rugby à XV, six en rugby à XIII, trois en cricket, trois en hockey une en lacrosse et une en netball. Cette revue de littérature conclue qu’il n’y a en fait ni consensus inter-, ni intra-disciplinaire, concernant les classifications des zones de course, ce qui rend difficile la comparaison des données d’un sport à l’autre. Elle souligne que la reproductibilité des données semblerait diminuer avec l’augmentation des courses à haute intensité (> 20 km.h-1 ) et que la validité augmente lorsque le volume de course est important. Enfin, la notion de distance relative (m.min-1 ) qui exprime la distance parcourue en rapport au temps de jeu, paraît comme un élément fondamental pour pouvoir comparer des données intra- ou inter-discipline d’études différentes. Cette revue n’a que peu traité les données relatives aux accélérations et aux impacts car peu d’articles s’y étaient attardés. Concernant les accélérations, les auteurs comptabilisaient seulement cinq études traitant de ces données qui en sport collectif, ont malgré tout leur importance ; pour autant, ils dénonçaient que le manque de données à ce sujet relevait certainement de l’incapacité des fabricants à assurer la validité de ces dernières (ce, avant l’arrivée des GPS à 10 Hz). Concernant les données d’impacts, seulement 14,3% des articles étudiés abordaient ce sujet ; c’est en Rugby à XV et à XIII, en comparant les données par poste, que les auteurs avaient porté le plus d’intérêt à ce paramètre qui, relatif aux phases de combat, fait partie intégrante de l’activité rugby. À notre connaissance, seules deux études se sont consacrées à l’analyse de la qualité des données d’accélérations, fournies par les accéléromètres intégrés aux balises GPS. Si Buchheit et coll. (2013) montrent à l’aide d’une analyse mécanique que les données d’accélération doivent être utilisées avec précaution car la variabilité inter-unité peut s’étendre de 1 à 56%, Akenhead et coll. (2013), ajoutent eux, que la précision au-delà des 4 m.s 2 est souvent réduite Des données récoltées par ces GPS, le principal paramètre observé dans un premier temps est celui de la distance totale (DT) parcourue en mètre par les joueurs. Il permet de donner une indication de la charge globale imposée par l’activité mais pour autant, ne nous renseigne pas sur l’intensité de cette charge. De fait dans un second temps, la DT est souvent relativisée au temps de jeu (distance relative), de façon à donner aux observateurs une information sur le « rythme » du match (exprimée en m.min-1 ). 30 Les premières analyses des mouvements en sport collectif fixent des zones de vitesse correspondantes chacune à une catégorie d’intensité. Comme expliqué dans la revue de littérature de Cummins et coll. (2013), ces catégories de course couvrent souvent quatre zones, par des allures allant de 0 à 36 km.h-1 , décrivant les déplacements de la marche jusqu’au sprint. Cependant, aucun consensus n’est établi concernant la définition des différentes zones. Ainsi, le nombre de catégories d’intensité varie en fonction des études. On retrouve néanmoins, presque systématiquement les catégories du type « station debout », « marche » et « jogging ». Les seuils de vitesse utilisés pour différencier ces catégories de course varient également d’une étude à l’autre. Dans l’étude de Suarez-Arrones et coll. (2012), nous avons l’exemple d’une catégorisation de course : l’activité de marche correspond à une vitesse comprise entre 0 - 6,0 km.h-1 , le jogging entre 6,1 - 12,0 km.h-1 , la course entre 12,1 - 14,0 km.h-1 , la course rapide entre 14,1 - 18,0 km.h-1 , la course à haute intensité entre 18,1 - 20,0 km.h-1 et l’activité de sprint au-delà des 20,1 km.h-1 . En comparaison, l’étude de Granatelli et coll. (2014) fait la distinction des catégories de course au travers d’un seuil arbitraire : l’activité à faible intensité entre 0,1 - 14 km.h-1 et celle à haute intensité supérieure à 14,1 km.h-1 . Pour aller plus loin dans l’analyse de l’exigence en sport collectif et afin d’observer les exigences physiques, Cahill et coll. (2013) en Rugby à XV, ont été les premiers à proposer des catégories d’intensité de course individualisées par rapport à la vitesse maximale (Vmax) des joueurs. C'est-à-dire qu’ils observaient les allures de course vis-à-vis de la plus grande vitesse (vitesse pic), qu’ils étaient capables d’atteindre sur un test de vitesse maximale. Lovell et Abt (2013) ajoutent par la suite l’intérêt d’observer aussi, les déplacements des joueurs en rapport à leurs vitesses maximales aérobies (VMA) afin de mieux se rendre compte de la dépense énergétique qui en résulte car c’est à VMA, que l’individu consomme le maximum d'oxygène ; autrement dit, c'est à cette allure qu’il atteint sa VO2max. La même année, Mendez-Villanueva et Buchheit mettent en application ce système de quantification et y ajoutent la notion de vitesse anaérobie de réserve (« anaerobic speed reserve », ASR), représentant la différence entre la Vmax et la VMA. Catégoriser les courses vis-à-vis de la VMA, de la Vmax et de l’ASR, permet aux analystes de performance d’observer à la fois les différents rythmes réalisés au cours des matchs mais aussi et surtout de pouvoir se projeter sur les dépenses énergétiques individuelles qui en découlent. 31 Ci-après, la Figure 2 illustre le déplacement d’un joueur pendant une séquence de jeu de 30 secondes au cours d’un match, séquence au cours de laquelle il réalise deux accélérations. Nous pouvons y observer les différentes vitesses atteintes et ainsi, le découpage de l’allure de course individualisée. Figure 2 : Déplacement d’un joueur pendant une séquence de jeu de 30 secondes. Découpage de l’allure de course individualisée et vitesses atteintes. Légende : Vmax : vitesse maximale ; VMA : vitesse maximale aérobie ; ASR : vitesse de réserve anaérobie Ainsi, l’analyse des déplacements des joueurs pourrait devenir un moyen d’objectiver la charge externe au cours d’un match. De plus, le temps passé dans chaque zone de course individualisée, peut orienter les préparateurs physiques dans la mise en place de futures séances de préparations physiques courues en rapport aux allures exigées par la discipline. En l’absence de méthode de référence concernant la méthode d’analyse de performance en sport collectif, toutes les techniques d’analyses préalablement explicitées, ont été évaluées comme capable de fournir des analyses de mouvement justes et réalistes, de la performance des joueurs (Higham et coll. 2012). De plus, les analyses basées sur la vidéo, les systèmes de caméra multiples et l’utilisation des GPS, sont toutes en capacité de détecter en compétition, les mêmes diminutions de performances (Randers et coll. 2010). 32 Cependant, les différences substantielles qui existent entre ces résultats suggèrent que des précautions soient prises lorsque l’on souhaite comparer entre elles ces données (Randers et coll. 2010 ; Harley et coll. 2011). Si l’analyse des données GPS est aujourd’hui une source d’informations importante à exploiter pour l’analyse de la performance, elle devrait sans nul doute se coupler systématiquement avec une analyse technique de l’activité. Par le biais d’une analyse notationnelle, nous pourrions alors appréhender de manière plus précise, la performance globale des joueurs au cours d’un match. Synthèse : Validité et reproductibilité, méthodes d’analyses des données GPS . Validité : elle augmente avec l’augmentation de la fréquence d’échantillonnage. . Reproductibilité : elle augmente avec l’augmentation du volume de course. . Difficulté de comparer les données GPS d’une étude à l’autre car il n’existe pas de méthode de référence concernant la classification des zones de course. . Catégoriser les courses vis-à-vis de la VMA, de la Vmax et de l’ASR, permet aux analystes de performance de se projeter sur les dépenses énergétiques individuelles des joueurs. 33 4. L’analyse notationnelle L’intérêt de l’analyse de l’efficacité en sport collectif prend tout son sens et beaucoup d’importance via le professionnalisme des différentes activités sportives. La construction de critères d’efficacité

DOCTORAL THESISDOCTORAL THESIS Sport Injury-Related Growth Theory-to-Practice Roy-Davis, Kylie Award date: 2017 Awarding institution: University of Roehampton General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 15. avr.. 2025 Sport Injury-Related Growth: Theory-to-Practice Kylie Roy-Davis A thesis submitted in partial fulfillment for the degree of PhD Department of Life Sciences University of Roehampton 2017 i This thesis is dedicated to Adam. ii Declaration This thesis is the author’s own work, and has not been previously submitted for an award of this university or any other institution. Signed:…………………………….. Date:……………………………….. STATEMENT 1 The content of the thesis is legally allowable under copyright legislation. Signed:…………………………….. Date:……………………………….. STATEMENT 2 I hereby give consent for my thesis, if accepted, to be available for photocopying and for interlibrary loan, and for the title and summary to be made available to outside organizations. Signed:…………………………….. Date:……………………………….. iii Summary This thesis explored the concept of sport injury-related growth (SIRG). Specifically, the mechanisms through which growth occurs and how it may be promoted for injured athletes. Study 1 used a grounded theory methodology to develop a context-specific theory. Aligning with a Straussian approach, data was collected using semi-structured interviews and analysed using open, axial, and selected coding. Findings revealed that the mechanisms of (a) meta-cognition, (b) positive reappraisal, (c) positive emotions, and (d) facilitative responses are what enable SIRG. These mechanisms are influenced by a combination of internal (e.g., personality) and external (e.g., received social support) factors. These factors enable injured athletes to alter their perception of their injury into an opportunity for growth, and it is by drawing upon and mobilizing a variety of these resources that athletes are able to experience SIRG. Dimensions of growth were psychosocial, physiological, and behavioral. Although this study produced a theory that explains the SIRG process, it does not propose specific techniques or therapies that encourage the development of growth. To address this issue, Study 2 aimed to investigate and identify evidence-based interventions that promote growth after experiencing adversity. To achieve this aim, a systematic review was conducted on literature pertaining to the promotion of growth for populations who have undergone a stressful experience (e.g., medical illness). In total, 34 studies were located and obtained that met the preplanned inclusion criteria. Within these 37 studies, three types of interventions were identified: emotional processing, cognitive processing, and combined techniques. The authors of the studies who successfully demonstrated the promotion of growth either identified or suggested that growth occurs through the mechanisms of cognitive restructuring and/or reappraisal. Other important considerations that were identified through this review were the duration and timing of the intervention in relation to the adverse event, and the importance of the intervention meeting the needs of the participants. Although this study offers valuable insight into how growth may be more successfully nurtured, the studies included within this review did not specifically focus on promoting growth for injured athletes. Consequently, Study 3 sought to complement this study by examining the practice-based experiential knowledge of sport psychologists who have worked with injured athletes in an applied manner. In total, 10 sport psychologists were purposively sampled and interviewed. Data was collected using a semi-structured interview guide and analysed using content analysis. Findings revealed a fluid development framework that consisted of 5 phases: (a) reactionary phase, (b) preparation phase, (c) reflection phase, (d) application phase, and (e) monitoring phase. Within each phase a set of corresponding strategies, skills, and tools were identified that the sport psychologists would utilize to match the needs of the athletes. The sport psychologists also identified a number of personal and environmental factors that either promoted or hindered the development of SIRG. Altogether, this thesis supports and extends research regarding growth and sport injury, as well as offering applied practitioners useful information for promoting SIRG. iv Table of Contents Page Dedication……………………………………………………………………………….... i Declaration……………………………………………………………………………….. ii Summary………………………………………………………………………………….iii Table of Contents…………………………………………………………………………iv Publications and Presentations……………...……………………….……….…...... ……ix Appendices………………………………………………………………………....……...x Tables……………………………………………………………………………………..xi Figures…………………………………………………………………………………... xii Acknowledgements……………………………………………………………………...xiii Chapter 1: Introduction…………………………………………………………………1 What is this Ph.D. about?.............................................................................................2 Background…………………………………………………………………………..2 Conducting research………………………………………………………………….4 Overview……………………………………………………………………….....….6 Chapter 2: Literature Review.........................................................................................11 Abstract ......................................................................................................................12 Introduction ................................................................................................................13 Responses to Sport Injury.....................................................................................13 Models and Theories of Sport Injury .............................................................14 v Responses to Sport Injury Research.....................................................................22 Emotional Responses .....................................................................................13 Coping Strategies ...........................................................................................25 Growth Research ..................................................................................................27 Models and Theories of Growth.....................................................................29 Growth Research ............................................................................................33 Sport Injury and Growth.......................................................................................35 Summary and Recommendation for Future Research................................................39 Chapter 3: A Grounded Theory of Sport Injury-Related Growth .............................43 Abstract ......................................................................................................................44 Introduction ................................................................................................................45 Methods......................................................................................................................49 Philosophical Orientation and Methodology........................................................49 Participants...........................................................................................................50 Data Collection and Procedure.............................................................................51 Data Analysis .......................................................................................................53 Results........................................................................................................................56 Sport Injury...........................................................................................................57 Meta-Cognition and Positive Reappraisal............................................................58 Positive Emotions and Facilitative Responses.....................................................59 Internal Resources................................................................................................63 External Resources...............................................................................................65 vi Sport Injury-Related Growth................................................................................69 Discussion ..................................................................................................................71 Chapter 4: Interventions to Promote Growth Following Adversity: A Systematic Review of Evidence-Based Practice (Study 2)...............................................................78 Abstract ......................................................................................................................79 Introduction ................................................................................................................80 Methods......................................................................................................................82 Design...................................................................................................................82 Inclusion Criteria..................................................................................................82 Search Strategy.....................................................................................................83 Shifting of Research Papers .................................................................................84 Results........................................................................................................................86 Emotional Processing Interventions.....................................................................86 Cognitive Techniques Interventions...................................................................103 Combined Techniques Interventions..................................................................107 Qualitative Interventions....................................................................................109 Discussion ................................................................................................................112 Chapter 5: Practice-Based Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists...................................123 Abstract ....................................................................................................................124 Introduction ..............................................................................................................125 vii Methods....................................................................................................................128 Design and Assumptions....................................................................................128 Sampling Procedure and Participants.................................................................128 Interview Guide..................................................................................................130 Data Analysis .....................................................................................................132 Results......................................................................................................................133 Reactionary Phase ..............................................................................................133 Preparation Phase ...............................................................................................138 Reflection Phase .................................................................................................141 Application Phase...............................................................................................144 Monitoring Phase ...............................................................................................149 Influential Factors of SIRG ................................................................................151 Athlete’s Personality ....................................................................................152 Team Environment/Culture..........................................................................154 Social Support Network ...............................................................................156 Athlete’s Free Time......................................................................................158 Discussion ................................................................................................................160 Chapter 6: General Discussion and Conclusions……………………………………168 Introduction ..............................................................................................................169 Summary of Studies ...........................................................................................169 Study 1: A Grounded Theory of Sport Injury-Related Growth..........................170 viii Study 2: Evidence Based Interventions to Promote Growth Following Adversity: A Systematic Review......................................................171 Study 3: Practice-Based Evidence of Facilitating Sport InjuryRelated Growth: Phases and Strategies Recommended by Sport Psychologists......................................................................................................172 Synthesis of Results Across Studies……………………………………………….173 Theoretical and Empirical Impact of this Thesis......................................................175 Theoretical Impact..............................................................................................175 Empirical Impact ................................................................................................179 Practical Implications...............................................................................................181 Strengths and Limitations.........................................................................................187 Future Research Recommendations.........................................................................188 Overall Conclusions.................................................................................................190 References.......................................................................................................................192 Appendices......................................................................................................................227 ix Publications and Presentations Journal Publications Roy-Davis, K., Wadey, R., & Evans, L. (2017). A grounded theory of sport injury-related growth. Sport, Exercise, and Performance Psychology, 6(1), 35-52. DOI: 10.1037/spy0000080 Conference Presentations Roy-Davis, K., Wadey, R.m & Evans, L. (2017). Practice-Based Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists. Poster session to be presented at the 2017 Association for Applied Sport Psychology (AASP) 32nd Annual Conference, Orlando, USA. x Appendices Page Appendix A. Participant consent form- Study 1..................................................................228 B. Participant debrief form- Study 1 ..................................................................231 C. Participant information sheet- Study 1 ..........................................................214 D. Interview Guide- Study 1...............................................................................236 E. Participant consent form- Study 3..................................................................243 F. Participant debrief form- Study 3 ..................................................................246 G. Interview Guide- Study 3...............................................................................249 xi Tables Table 1. Qualitative Assessment for Quantitative Studies ................................................88 Table 2. Emotional Processing Interventions ....................................................................91 Table 3. Cognitive Interventions....................................................................................... 93 Table 4. Combined Interventions...................................................................................... 96 Table 5. Qualitative Interventions..................................................................................... 97 Table 6. Measures of Growth used in Interventions: Abbreviations and Full Titles.........98 Table 7. Sport Psychologist’s Overall Strategies and Skills............................................145 Table 8. Sport Psychologist’s Overall Tools ...................................................................147 xii Figures Figure 1. Wiese-Bjornstal, D., Smith, A., Shaffer, S., & Morrey, M. (1998). An integrated model of response to sport injury: Psychological and sociological dynamics. Journal of Applied Sport Psychology, 10, 46-68 .........................16 Figure 2. Brewer, B., Andersen, M, & Van Raalte, J. (2002). Psychological aspects of sport injury rehabilitation: Toward a biopsychosocial approach. In D. Mostofsky & L. Zaichkowsky (Eds.). Medical and psychological aspects of sport and exercise, (pp. 44-54). Morgantown, West Virginia: Fitness Information Technology ....................................................................................................19 Figure 3. Kubler-Ross, E. (2009). On death and dying: What the dying have to teach doctors, nurses, clergy and their own families. London, United Kingdom: Taylor & Francis...............................................................................................21 Figure 4. Tedeschi, R., & Calhoun, L. (1995). Trauma and transformation: Growing in the aftermath of suffering. Thousand Oaks, CA: Sage Publications..............30 Figure 5. Roy-Davis, K., Wadey, R., & Evans, L. (2017). A grounded theory of sport injury-related growth. Sport, Exercise, and Performance Psychology, 6(1), 35-52..........................................................................................................................56 Figure 6. Shifting of researcher papers..............................................................................85 Figure 7. Conceptual Model of the Development of Sport Injury-Related Growth .......................................................................................................................................................135 xiii Acknowledgments First and foremost, I want to thank my supervisors, Dr. Ross Wadey and Dr. Lynne Evans, as well as my Director of Studies, Dr. Ceri Diss for their continuous support and encouragement during this thesis. I cannot express enough how much I appreciate your time and attention. Thank you for giving me this wonderful opportunity. Particularly Ross, thank you for your guidance and for being a truly wonderful supervisor. A very special thank you to my family. Mom, you have always been my biggest cheerleader and believed in me when I didn’t believe in myself. Grandma and Grandpa, thank you for your enthusiasm, and I’m sorry that I’ve been away for so long. To the rest of my family, thank you for your love and understanding. Thank you to all my friends, both in the U.K. and U.S.A. You’re all amazing, beautiful people and you’ve helped me so much whether you knew it or not. To my fellow PhD candidates, thank you for the happy memories I’ll take with me. It was great sharing this journey with you. I would also like to thank all my participants. I truly appreciate that you gave me your time and shared your stories. This thesis would not exist without you. Lastly, thank you to Adam. You’re the best friend and husband I could ask for. You’re my rock. 1 Chapter 1: Introduction 2 What is this PhD about? The aim of this Ph.D. was to better understand the sport injury experience, particularly how sport injury may actually provide beneficial aspects, commonly referred to as “growth”, for athletes who have sustained injury. More specifically, this programme of research sought to provide practical information that may further assist individuals who work with injured athletes in an applied manner. Through the use of qualitative research and systematic review, this thesis explored the sport injury experience as well as the promotion of growth for injured athletes. The purpose of the first study, A Grounded Theory of Sport Injury-Related Growth, was to develop a context-specific theory pertaining to the development of growth following a sport injury. The second study, Interventions to Promote Growth Following Adversity: A Systematic Review of EvidenceBased Practice, used a systematic review methodology to explore interventions that have been used to promote growth for traumatized populations. The final study, PracticeBased Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists, investigated the experiences and expertise of sport psychologists who have worked with injured athletes in order to further comprehend the issues surrounding growth cultivation in a practical setting. Collectively, these three studies have helped to advance the knowledge of sport injury, in particular the ways in which growth may be developed as a result of a sport-related injury. Background The topic of sport injury has long since been an interest of mine, however, I was always drawn to the field of psychology. Fortunately, despite a lifetime of involvement in 3 sport and physical activity I never experienced a significant sport injury, yet I would constantly see friends and teammates struggle through an injury they had sustained through sport. I knew that I wanted to help them, but I did not know how. Although I would often try to help alleviate the burden of their injury, I could see the toll their injury was having on them, not just physically but mentally and emotionally as well. In the days before I even began this Ph.D., when I was still trying to figure out what a thesis was and what mine may look like I met with Dr. Ross Wadey. During this meeting he told me about his idea for a programme of research that would begin with the development of a theory related to sport injury-related growth. Although I was vaguely familiar with the concept of post-traumatic growth, I had not yet seen this concept related to sport injury. This quickly sparked a change in my perception of sport injury- the idea that athletes may actually return to their sport better than they were before their injury. This idea went beyond exciting me; it felt right to me and I could immediately see the contribution this research could have for the field of sport injury. Suddenly, I was seeing sport injuries differently. While it was, and is still, my opinion that sport injury will never be a good thing- no one wants to be injured- but maybe for those unlucky ones who do get injured, my research could help these athletes be a little less unlucky. Maybe sport injuries did not have to be this terrible, debilitative thing. Maybe sport injuries could become an experience that helps athletes. Rather than muddling through their recovery, injured athletes could potentially be guided to achievements they had never reached before or change in ways that will positively affect them. This created not only a personal revelation, but also became the inspiration and focus for my Ph.D. 4 Conducting Research Although I knew that the general idea driving my thesis was exploring the concept of growth following sport injury, specifically with the aim of creating a contextspecific theory, I needed to decide how this aim would be achieved. Immediately I knew that this first research effort would be a qualitative nature, a methodology I had become familiar with during my undergraduate and graduate studies, but had never personally undertaken. From my time as a student before starting this Ph.D., I knew that research could be of either a qualitative or qualitative nature, or, in some instances, a mixture of the two. I had conducted quantitative research as a Masters student, and can appreciate the satisfaction questionnaires and a numerical value can bring. However, as someone who hesitates around numbers and gravitates towards stories, I knew that my real interest was in qualitative research. While I was confident that I could rise to the personal challenge a numbers-based study, I instinctively knew that I wanted more than that- I wanted the story beyond the statistics. I wanted to discover and explore the feelings and experiences of these athletes, and wholeheartedly embraced the qualitative approach. Despite my tendency to reduce research methodology to its most basic elements (i.e., quantitative research is numbers, qualitative research is words), this does not fully encapsulate the qualitative research approach. Indeed, the term “qualitative research” lacks a clear definition, and is often defined as simply being the counterpoint to quantitative research (Martin, 2011). Qualitative research does, however, hold common characteristics, such as its search for meanings, subjectivity, context, and reflexivity (Sparkes & Smith, 2014). So while quantitative research is focused on measuring facts and explaining the relationship between these facts in a technical manner, the goal of 5 qualitative research is to gain understanding of how people experience and make sense of the world (Smith & Caddick, 2012). I knew that this was the research I wanted to conduct and I began to familiarize myself with different qualitative approaches, namely the grounded theory methodology, as I knew this would be the research methodology of my first study. What I was unaware of at this point, was the importance of determining my own views of ontology and epistemology. A bit bewildered at first- wasn’t I studying psychology, not philosophy? I soon realized the significance of these concepts and the relationship between personal viewpoints and research design. So rather than rustling up an interview guide and diving into date collection as I had initially imagined, I found myself pondering on various philosophical ideals and reflecting on my own interpretations of reality and knowledge. Eventually, and with much deliberation, I decided my personal beliefs were those of a post-positivist with critical realism and modified dualism/objectivism. To elaborate, critical realism refers to the idea that the reality that humans perceive is influenced by unobservable events and it is only through attempting to understand these events that we are able to comprehend the social world. Modified dualism/objectivism refers to my belief that as a researcher, it is my duty to make efforts to minimize any effect my presence may have on the research process. Upon deciding these views, I could begin to plan and conduct my research accordingly. Throughout this programme of study, as I progressed through my research and decided on the ensuing steps to be taken, I would constantly question whether the research I was designing and analyzing aligned with my personal beliefs. These beliefs have important 6 implications, as my personal assumptions influenced how I approached and conducted the research within this thesis. Overview of the Thesis This dissertation consists of six chapters in total, and contains three original studies. This introduction serves as the first chapter and is presented for the purpose of providing clarity and to prime the reader for the forthcoming chapters. Following this Introduction, Chapter II, Literature Review, is presented to provide a critical review and synthesis of the current literature related to the areas of responses to sport injury, growth research, and sport injury and growth. Specifically, the aims of this chapter are to (a) provide information on the existent research pertaining to sport injury as well as the models and theories of sport injury; (b) review the research related to the emotional responses of athletes upon sustaining injury, and the reported coping strategies these athletes subsequently employ; (c) present and explain the concept of growth following a traumatic or stressful event, including descriptions and critical appraisals of models and theories of growth, as well as describing and critically reviewing prominent growth research; (d) draw together the concepts of sport injury and growth by explaining and critically appraising research that has focused on this area; and (e) summarize the information presented in this chapter and provide recommendations for future research, before concluding with the aims and rationale for this programme of research. Chapter III, A Grounded Theory of Sport Injury-Related Growth, reports results from Study 1, which aimed to develop a context-specific theory of growth following a sport injury by exploring the experiences of injured athletes who perceived a degree of 7 growth from their own injury. A grounded theory methodology was conducted, with 37 injured athletes taking part and providing a total of 70 interviews collected through the use of semi-structured interviews. After each interview, the data was transcribed and analyzed using a method of open, axial, and selective coding. Findings reveal that injured athletes are able to experience the development of growth through the mechanisms of metacognition, positive reappraisal, positive emotions, and facilitative responses. These mechanisms are influenced by the presence of a combination of internal and external factors, which if support the development of growth, will positively affect the athlete and result in a perception of injury has holding inherent opportunities. This theory provides greater insight into the injury experience, particularly the role and occurrence of growth related to sport injury, illuminating why some athletes may be able to experience the development of growth while others are not. However, this study did not provide information on how this growth process may be encouraged in an applied setting, and therefore the aim for the following study focused on delving into the topic of specific interventions that may successfully promote growth. Chapter IV, Interventions to Promote Growth Adversity: A Systematic Review of Evidence-Based Practice, gives a description and the results from the second study of this thesis. This study used a systematic review methodology to investigate the use of interventions that have demonstrated success in promoting post-traumatic growth. As the ultimate goal for this thesis is to provide information that will aid applied practitioners working with injured athletes, the desired research question at the commencement of this study was to focus on research conducted regarding post-traumatic growth and sport injury. However, as this is a relatively new area of research and there is insufficient, if 8 any, existent literature that addresses this research question, the goal of this review shifted to concentrate on any intervention-based research conducted with the goal of fostering growth for a population that had experienced a stressful or traumatic event. In total, 37 studies were identified that met the pre-determined inclusion criteria. These 37 interventions fell into 4 categories: (a) emotional processing- seeking to provide the participant with a sense of closure, catharsis, or fulfillment; (b) cognitive strategieswhich attempt to bestow participants with the relevant tools to aid the post-traumatic growth process; (c) combined technique- interventions that drew upon both emotional and cognitive processing techniques; and (d) qualitative interventions- studies which used interventions aimed at promoting growth but focused on gaining rich, in-depth information gathered through interviews and observations. Among the studies that successfully demonstrated the encouragement of growth, the researchers either identified or suggested that these interventions were able to foster growth through the mechanisms of cognitive restructuring and/or reappraisal. This review also identified that both the duration of the intervention and the timing of the intervention implementation after the traumatic event are important considerations. These findings illuminate certain methods through which growth may be better encouraged yet these studies did not focus on promoting growth for injured athletes. The need to further understand the process of urging growth for injured athletes provided the rationale for the following study. Chapter V, Practice-Based Evidence of Facilitating Sport Injury-Related Growth: Phases and Strategies Recommended by Sport Psychologists, explains the procedure and results of the final study in this programme of research. The goal of this study was to gather information about the real-world experiences of sport psychologists who work 9 with injured athletes in a practical setting. In particular, this research sought to explore any issues related to the promotion of growth for applied practitioner working with injured athletes and investigate how these practitioners have been able to successfully encourage growth for injured athletes. This study specifically decided to use sport psychologists for participants, as these individuals were more likely to be familiar with the concepts of post-traumatic growth and therefore provide richer, more in-depth data. Ten sport psychologists were purposively selected for their expertise and experiential knowledge and data was gathered through the use of semi-structured interviews. Analysis of the data revealed that the sport psychologists were able to encourage growth by effectively guiding the injured athlete through a fluid developmental framework. This framework consists of five phases: (a) reactionary phase, (b) preparation phase, (c) reflection phase, (d) application phase, and (e) monitoring phase. The sport psychologists also reported using a variety of specific strategies, skills, and tools that would be employed to match the current needs of the athletes. Finally, a number of personal and environmental factors were identified that either promoted or hindered the development of growth. These results offer useful information to applied practitioners and in this way extend the previous research. Chapter VI, General Discussion and Conclusions, is the final chapter and brings this dissertation to a close by summarizing the three studies and discussing their contribution to knowledge. After this review of the three original studies and their results, this chapter concentrates of the theoretical and empirical impact, as well as the practical implication of this research. Thereafter, the strengths and limitations of this thesis are 10 discussed and recommendations for avenues of future research are presented. Finally, the central aspects of this programme of research are drawn together in an overall conclusion. 11 Chapter 2: Literature Review 12 Abstract The purpose of this chapter was to provide a critical review of the psychology of sport injury literature, the concept of growth following adversity, and recent research that has aimed to integrate these two bodies of literature Specifically, this reviews describes a model, theories, and research related to the psychological response to sport injury, namely the integrated model of response to sport injury developed by Wiese-Bjornstal, Smith, Shaffer, and Morrey (1998). It also synthesizes the literature related to models, theories and research on post-traumatic growth. Lastly, it draws these two concepts together in the context of growth following a sport injury. The review considers both conceptual and methodological issues across the bodies of literature. The chapter concludes with a summary and recommendations for areas of future research. 13 Introduction The purpose of this chapter is to provide a critical review of the research related to the concepts of sport injury and growth following adversity as a basis for the rationale for this programme of research. The chapter has been divided into four sections: Responses to Sport Injury, Growth Following Adversity, Sport Injury and Growth, and Summary. The first section, Response to Sport Injury, will synthesize the research into athletes’ psychological responses to sport injury. The second section, Growth Following Adversity, will explore the literature related to benefits associated with undergoing a traumatic or stressful event across a variety of populations and types of stressful events. The third section, Sport Injury and Growth, will examine the research relating to the benefits derived from experiencing a sport-based injury. This review has been separated so as to introduce the reader first to the topic of Responses to Sport Injury, as this is considered the primary concept of this sport psychology-based thesis. However, this thesis is also concerned with the field of post-traumatic growth and therefore the following section, Growth Following Adversity, helps facilitate knowledge translation between other fields of research and sport psychology by contextualizing growth following sport injury and the large body of research exploring growth following adversity. Finally, to draw these two fields together, the third section, Sport Injury and Growth, provides a contextualized understanding of growth within the context of sport injury. The fourth and final section will provide a summary of the chapter and recommendations for future research. Responses to Sport Injury Although research into the psychology of sport injury dates back to the 1960’s, 14 the majority of it has been conducted over the last 20 years. Findings in this field have indicated that athletes who have sustained injury undergo cognitive, emotional, and behavioural changes, the majority of which have been considered unpleasant in nature (Evans, Mitchell, & Jones, 2006). Indeed, injury has been viewed as a largely negative experience characterized by heightened levels of depression, frustration, and helplessness (e.g., Evans & Hardy, 1995; Leddy, Lambert, & Ogles, 1994). Where positive effects of injury were reported they emerged serendipitously (e.g., Bianco, Malo, & Orlick, 1999; Ford & Gordon, 1999; Hurley, Moran, & Guerin, 2007; Podlog & Eklund, 2006; San Jose, 2003; Tracey, 2003). However, in recent years, researchers have begun to investigate positive consequences related to sport injury (e.g., Udry, Gould, Bridges, & Beck, 1997) encouraging a shift to a more inclusive view of the injury experience (Wadey, Evans, Evans, & Mitchell, 2011), wherein both negative and positive experiences are considered. Unfortunately, to date these studies have been somewhat solitary in nature, and not provided a focused, systematic approach to this important line of enquiry. A more inclusive view of the research to date, suggests that injured athletes report both negative (i.e., anxiety) and positive (i.e., increased resilience) responses, suggesting that injury may not be an inherently a negative experience as originally conceived. Indeed, contrary to the prevailing belief that injury is a largely negative experience, in recent years research has highlighted the ways in which athletes are able to benefit from their injury and even experience a degree of growth as a result of it (e.g., Galli & Vealey, 2008; Podlog & Eklund, 2006; Tracey, 2011; Udry et al., 1997; Wadey et al., 2011; Wadey, Evans, Hanton, & Neil, 2012). 15 Models and Theories of Sport Injury As the field of sport injury research has grown, researchers have endeavored to provide explanations of the injury experience and the underlying processes through the development and application of various models and theories. These models and theories include the integrated model of response to sport injury (Wiese-Bjornstal, Smith, Shaffer, & Morrey, 1998), biopsychosocial model of sport injury rehabilitation (Brewer, 2003), stage-based grief response models (Kubler-Ross, 2009), self-determination theory (Deci & Ryan, 2011), cognitive-motivational relational theory of emotion (Lazarus, 2000), selfefficacy theory (Bandura, 1994), reversal theory (Apter, 1989), personal investment theory (Maehr, & Braskamp, 1986), and protection motivation theory (Rogers, & Prentice-Dunn, 1997). The first three of these - the integrated model of response to sport injury, the biopsychosocial model of sport injury rehabilitation, and the stage-based grief response - will now be discussed, as these are typically the most adopted within the sport injury research. Indeed, the factors and processes identified by these models, and theory, have also been identified in research pertaining to post-traumatic growth; in this way, these models and theory show promise for making connections between the fields of sport injury and growth following adversity. Of particular importance to this programme of research, is the integrated model of response to sport injury (Wiese-Bjornstal et al., 1998), as this model has received the most empirical support to date (Wadey & evans, 2011), and has served as the foundation for this thesis. Although each model and theory has specific strengths, the model that has received the most attention in the literature is the integrated model of response to sport injury (Wiese-Bjornstal et al., 1998). According to this model (see Figure 1), a 16 Stress Response Sport Injury History of Stressors Coping Resources Intervention Personal Factors Situational Factors Cognitive Appraisal Goal adjustment Rate of perceived recovery Self-perceptions Beliefs and attributes Sense of loss or relief Cognitive coping Injury History Severity Type Perceived cause Recovery status Individual Differences Psychological Personality Self-perception Self-motivation Motivational orientation Pain tolerance Athletic identity Coping skills Psychological skills History of stressors Mood states Demographic Gender Age Ethnicity Socioeconomic status Prior sport experience Physical Ergogenic aids Physical health status Disordered eating Sport Type Level of competition Time in season Playing status Practice vs. game Scholarship status Social Teammate influences Coach influences Family dynamics Sports medicine team influences Social support provision Sport ethic/philosophy Environmental Rehabilitation environment Accessibility to rehabilitation Behavioural Response Adherence to rehabilitation Use of PST strategies Use/disuse of social support Risk taking behaviours Effort and intensity Malingering Behavioural coping Emotional Response Fear of unknown Tension, anger, depression Frustration, boredom Positive attitude/outlook Grief Emotional coping Recovery Outcomes -Psychosocial -Physical Figure 1. Wiese-Bjornstal Integrated Model of Response to Sport Injury 17 combination of pre-injury and post-injury variables influence an athlete’s responses to injury and their ensuing recovery outcome. Factors such as personality (e.g., perfectionism), history of stressors (e.g., previous injury/injuries), coping resources (e.g., psychological skills), and interventions (e.g., stress management) comprise the pre-injury variables. Post-injury variables include personal factors (e.g., severity of injury) and situational factors (e.g., time of competitive season). These factors influence an athlete’s cognitive appraisal of their injury and rehabilitation, and their emotional and behavioural responses, and recovery outcome. For example, a runner who has incurred his second knee injury three months before the start of the competitive season, experienced this injury previously (i.e., personal factor/history of stressors), but has sufficient time before the season begins (i.e., situational factors), might have a positive attitude about making a full recovery (i.e., cognitive and emotional response). This in turn could affect his adherence to his rehabilitation programme (i.e., behavioural response), resulting in a shorter, more successful recovery process and returning to competition at an equivalent, or even higher level of functioning than previously (i.e., recovery outcome). In this instance, an athlete may exhibit signs of growth resulting the injury. This model, although well-developed and widely used, however, does not provide a detailed explanation of the mechanisms through which athletes may experience the full range of possible recovery outcomes. More recently, Brewer (2003) developed the biopsychosocial model (see Figure 2), which integrates the frameworks of existing models of sport injury rehabilitation (e.g., Wiese-Bjornstal et al., 1998) with more general models of health outcomes (e.g., Cohen & Rodriguez, 1995). The biopsychosocial model is comprised of seven dimensions: 18 injury characteristics, sociodemographic factors, biological factors, social and contextual factors, intermediate biopsychological outcomes, and sport injury rehabilitation outcomes. In this model, injury characteristics refers to the nature of the injury (e.g., type, location, severity, history), which together with the individual’s sociodemographic factors (e.g., age, gender, race/ethnicity, and socioeconomic status) will influence the biological (e.g., immune functioning), psychological (e.g., personality), and social/contextual (e.g., life stress) factors. These three factors will subsequently affect the intermediate biopsychological outcomes, such as range of motion, strength, pain, and recovery rate. Finally, these intermediate outcomes will influence the rehabilitation outcomes, for example, functional performance, quality of life post-injury, treatment satisfaction, and desire and readiness to return to sport. Within this model, psychological factors play a unique, central role, having a direct bidirectional relationship with biological and socio-contextual factors, and the resulting intermediate and final recovery outcomes. While this model provides a holistic framework that helps to explain the process of sport injury rehabilitation, it does not offer an explanation of the relationships between the specific psychological variables. Prior to models that were specifically developed in a sport injury context, sport injury research often drew upon the stage-based grief model developed by Kubler-Ross (2009). This model (see Figure 3), which was derived to explain the emotional experiences of the terminally ill, postulates that grieving individuals will experience five stages: shock and denial, anger, bargaining, depression, and acceptance. Shock and denial, the first stage, is characterised by an individual’s failure to accept their current situation. This denial is reported to function as a buffer, affording the individual time to 19 Psychological Factors - Personality - Affect - Behaviour Injury Characteristics - Type - Location - Antecedents (history) - Cause - Severity Socio-demographic Characteristics - Age - Gender - Race/ethnicity - Socio-economic status Biological Factors - Endocrine - Respiration - Metabolism - Tissue repair - Sleep - Nutrition - Circulation - Immune functioning - Neurochemistry Social/contextual Factors - Social network - Life stress - Situational characteristics - Rehabilitation environment Biopsychological Intermediate Outcomes - Range of motion - Strength - Endurance - Joint elasticity - Rate of recovery - Pain Sport Injury Rehabilitation Outcomes - Functional performance - Quality of life - Satisfaction of treatment - Readiness to return to sport Figure 2. Biopsychosocial Model. 20 begin mobilising psychological defences. The second stage is characterised by anger, which is directed either externally (e.g., coach) or internally (i.e., self) and is fuelled by a sense of betrayal. Next, a stage of bargaining, is marked by the individual attempting to find a sense of resolution by offering pledges; this part of the process is typically kept secret or only shared with those the individual deems trustworthy. A period of depression follows, marked by symptoms such as social withdrawal, hopelessness, and unproductiveness. This depressive stage appears to be the longest period within the grief process and is considered to serve as a tool to facilitate acceptance of the impending loss. In the final stage of acceptance, they acknowledge their loss and its consequences. While reaching this stage does not denote a sense of happiness, it does signify the completion of the individual’s progression through the grieving process. Although developed for a different population, sport injury researchers have argued the applicability of grief to an athletic population, positing that athletes’ exhibit a comparable grief response upon sustaining injury (Evans & Hardy, 1995). This grief is postulated to be due to the significant personal loss that occurs as the result of the injury and the interruption it causes to an athlete’s investment in their training and sport participation (Brewer, 1999; Van Der Poel, J., & Nel, P., 2011). However, a number of researchers have questioned the relevance of this model to the sports injury process, not least because of the impermanent nature of most injuries (Rose & Jevne, 1993; Udry et al., 1998). The strengths of the integrated model of sport injury response and the biopsychosial model are that they were developed for sport injury and so are contextual to this field of research (e.g., Brewer et al., 2002; Wiese-Bjornstal et al., 1998). Likewise, the Kubler-Ross stage-based model of grief provides insight into the process that injured 21 Figure 3, Kubler-Ross Stages of Grief Model athletes may face, particularly when the potential for loss if great and their identity as an athlete is threatened. Although these models, alongside others not discussed within this literature review, have aided our knowledge and understanding of specific concepts in an injury context, they are limited in describing and explaining certain phenomena. These limitations include firstly, a failure to define, delimit, and describe specific recovery outcomes, which is essential for elucidating the recovery process and associated outcomes. Also, across these models and theories is a failure to explain the mechanisms for attaining certain recovery outcomes. For example, are there different processes for different recovery outcomes? It is important to ascertain these mechanisms to guide future research and theory development. Finally, the models described above were not Time Process Denial Anger Depression Bargaining Acceptance 22 designed to direct interventions. Indeed, models need to bridge the gap between theory and practice. For example, what interventions should practitioners use to help foster desirable, and prevent undesirable, recovery outcomes? Responses to Sport Injury Research Upon sustaining an injury, athletes are likely to experience a range of emotional, cognitive, and behavioural responses (Evan, Mitchell, & Jones, 2006). As discussed in the previous section, a number of models regarding the response to and rehabilitation from sport injury have been proposed in the sport injury literature. The model that has received the most attention in the response to sport injury research is the integrated model of response to sport injury developed by Wiese-Bjornstal et al. (1998). Researchers have focused on various aspects described in the model including: cognitive appraisal (e.g., Albinson & Petrie, 2003; Chung, 2012; Daly, Brewer, Van-Raalte, Petitpas, & Sklar, 1995; Ruddock-Hudson, O’Halloran, & Murphy, 2012; Weiss & Ebbeck, 1996), social support (e.g., Abgarov, Jeffrey-Tosoni, Baker, & Fraser-Thomas, 2012; Mitchell, 2011; Rees, Mitchell, Evans, & Hardy, 2010; Rees, Smith, & Sparkes, 2003), psychological skills (e.g., Hare, Evans, & Carlow, 2008; Nordin-Bates et al., 2011; Wesch et al., 2012), adherence to rehabilitation (e.g., Marshall, Donovan-Hall, & Ryall, 2012), interventions (e.g., Rock & Jones, 2010), recovery outcomes (e.g., Brewer, 2010), and a number of personal (e.g., athletic identity; Brewer, Cornelius, & Van Raalte, 2010) and situational factors (e.g., timing of injury; Gayman & Crossman, 2003). As it is beyond the scope of this review to examine the research pertaining to each of these variables, the following sections will provide a critical discussion of injured athletes’ emotional responses and coping attempts, as these concepts are germane to this thesis and are prominently featured 23 in both the literature regarding sport injury responses as well as the literature regarding post-traumatic growth. Emotional responses. The initial period following injury occurrence is typically characterized by negative feelings, such as frustration, anger, and depression (e.g., Clement, Arvinen-Barrow, & Fetty, 2015). For example, Mainwaring et al.’s (2004) reported a significant spike in depression, confusion, and total mood disturbance in athletes immediately after injury occurrence; emotions that subsided three weeks after injury, as the athletes began to cope with their situation. To better understand the reactions related to sport injury, Udry et al. (1998) interviewed 21 elite skiers about their responses after sustaining season-ending injuries. In total, 136 psychological reactions were identified and categorized into four dimensions: injury-relevant information processing-awareness (e.g., questioning), emotional upheaval/reactive behaviour (e.g., emotional agitation), positive outlook/coping attempts (e.g., good attitude/optimism) and other (e.g., ambivalence). These results further highlight the temporal nature of psychological reactions to injury, as athletes demonstrated a need to first process their injury-relevant information before responding emotionally. However, the aim of this study was not to determine the temporal sequence of psychological reactions, but to investigate the range of responses that occur. This concept supports, and extends, the findings of Quackenbush and Crossman (1994) who surveyed 25 injured athletes and identified 48 emotional reactions related to the injury experience. Of these 48 reported emotions, 36 were positive (e.g., hopeful) and 12 were negative (e.g., frustrated), and likewise displayed a temporal element, with negative emotions decreasing over time and positive emotions increasing. 24 Subsequent studies further suggest that athletes’ emotions are likely to shift and become more positive as they progress through their recovery (e.g., Madrigal & Gill, 2014). However, injury onset is generally found to be associated with the experience of numerous negative emotions such as fear, anger, or depression (Faris, 1985). Rehabilitation is typically characterized as a period that includes discouragement, frustration, and isolation, while return to sport is associated with emotions such as impatience, anxiety, anticipation, and increased confidence (e.g., Bianco, 2001; Granito, 2001; Johnston & Carroll, 1998). In Tracey’s (2003) exploration of college athletes’ recovery from moderate to severe injuries, results showed that emotions fluctuated in the time after injury, characterized by feelings of loss, lowered self-esteem, anger, and frustration. Over time, however, athletes’ view of their injury began to evolve and injury was instead perceived as a challenge and was approached with a positive attitude. Ultimately, these athletes acknowledged that their injury and rehabilitation was a process that facilitated greater self-understanding (e.g., inner strength) and appreciation (e.g., not taking health for granted). Ruddock-Hudson et al., (2014) investigated the emotional reactions of Australian League Football players and found that the severity of the injury appears to moderate athletes’ emotional reactions, with minor and severe and/or long-term injuries showing distinct emotional variations. Minor injuries seem to present little concern or limitations for athletes and so are responded to more positively and optimistically. Conversely, longterm injuries, such as knee reconstructions, invoke negative emotional responses and are viewed as more challenging. Social support is another factor that moderates emotional responses to sport injury, however, this effect diminishes with minor injuries. 25 Coping strategies. Sport injury is an experience associated with a high degree of strain, leading researchers to focus on the coping strategies used by injured athletes during injury onset, rehabilitation, and return to sport (e.g., Evans, Wadey, Hanton, & Mitchell, 2012). Coping is defined as the “constantly changing cognitive and behavioural efforts to manage specific external and/or internal demands that are appraised as taxing or exceeding the resources of the person” (Lazarus & Folkman, 1984, p. 141). Just as athletes experience a range of emotional responses as a result of a sport injury, they draw upon a variety of coping strategies, specifically, emotion- or problem- focused. Emotionfocused coping strategies aim to manage the negative emotions associated with the stressor (e.g., emotional disclosure). Problem-focused coping strategies concentrate on tackling the stressful situation (e.g., planning). More recently, researchers have explored the use of avoidant coping (e.g, Allen, Greenlees, & Jones, 2011; Carson & Polman, 2010), which refers to strategies used to avoid the situation through distraction (e.g., cognitive distancing) or social diversion (e.g., walking away). In this way, avoidance coping strategies may facilitate control over short-term emotional states and has been observed to be a strategy regularly used by athletes to deal with acute stress during sport participation (Nicholls, Holt, Polman, & Bloomfield, 2006). However, avoidant coping is generally associated with a number of psychological and physiological outcomes and is suggested to be maladaptive long term (e.g., Kim & Duda, 2003). Other research on coping skills related to sports injury reveal that athletes seek to gather information regarding their rehabilitation to gain a better understanding on the route to recovery (Carson & Polman, 2008), a form of problem-focused coping. Instances of emotionfocused coping strategies throughout the sport injury process (e.g., Udry et al., 1998; 26 Wadey et al., 2012b) include venting of emotions, seeking emotional social support, positive self-talk, and reframing negative thoughts and emotions. The possession and employment of coping skills appear to be shaped in part by instances of past adversity (Bejar & Butryn, 2016). Being exposed to stressful events previously may enable athlete to feel better prepared to face stressors, such as sport injury. Athletes exhibit high degrees of perseverance through their participation in sport and it is speculated that this determined approach helps athletes to cope with their injury. In Albinson and Petrie’s (2003) examination in cognitive appraisals, stress, and coping after sports injury, cognitive appraisals were found to be related to the coping strategies used by injured athletes. Specifically, athletes’ primary and secondary appraisals of their injury related to their coping strategies, with athletes who scored higher in mood disturbance during this period demonstrating higher occurrences of avoidance coping techniques. Findings from this study suggest that the first week post-injury may be a crucial time-point for athletes’ appraisals, as this appraisal will influence athletes’ coping strategies throughout the remainder of their recovery. For example, athletes that utilized avoidant coping techniques at the seven-day mark after injury onset also exhibited less cognitive active coping (i.e., attempts to manage appraisal of stressful event) during subsequent assessments. This suggests that helping injured athletes to manage their cognitive appraisals will also influence their engagement in behaviour aimed at dealing with their injury and its affects. Johnston and Caroll (2000) also found a temporal element, as their results showed that coping varied as a function of stage in rehabilitation. It was also revealed that the use of coping strategies declined over the course of rehabilitation, showing that rather than 27 shifting coping strategies, athletes’ use of coping declined overall as they progressed through recovery. Furthermore, coping appeared to be a stable characteristic of individuals, with no clear situational-specific coping strategy emerged from the data. However, results did demonstrate that participants preferred informational and emotional support in the middle and towards the end of their rehabilitation rather than at the beginning. This may be due to the athletes in their study being less receptive and regarding these types of support to be unnecessary during injury onset to deal with the intense emotions that characterize it. Growth Research Historically, both research and anecdotal evidence has postulated how personal gain can be derived from experiences of overcoming adversity (Joseph & Linley, 2004). However, it has not been until recently that growth following adversity has been studied with empirical and theoretical rigor (e.g., Calhoun & Tedeschi, 2006; Carver, 1998; Heffernon, Grealy, & Mutrie, 2009; Joseph & Linley, 2008; Weiss & Berger, 2010). Growth, defined as the perceived positive change that elevates a person to a higher level of functioning after enduring a stressful or distressing event (e.g., Kampman, Heffernon, Wilson, & Beale, 2015), can be personal (e.g., greater appreciation), psychological (e.g., increased confidence), social (e.g., strengthened relationships), and/or behavioural (e.g., improved coping skills) (e.g., Heffernon et al., 2009). Proposed mechanisms that support, or hinder, the development of growth include deliberate rumination, meaning-making, and social support (Tedeschi & Calhoun, 2004). Growth may also be explained through the prism of mindsets (Dweck, 2006; 2007; 2012). According to Dweck, individuals lie on a spectrum between either a fixed 28 mindset or a growth mindset. Those who lie closer to the end of fixed mindsets believe that each person has a finite amount of un-increasable intelli

THE GREAT COURSESDavid-Dorian Ross International MasterTai Chi Instructor Course Guidebook PUBLISHED BY: THE GREAT COURSES Corporate Headquarters 4840 Westfields Boulevard, Suite 500 Chantilly, Virginia 20151-2299 Phone: 1-800-832-2412 Fax: 703-378-3819 www.thegreatcourses.com Copyright © The Teaching Company, 2017 Printed in the United States of America This book is in copyright. All rights reserved. Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of The Teaching Company. i David-Dorian Ross, B.A. International Master Tai Chi Instructor David-Dorian Ross is the founder and CEO of TaijiFit and the creator of the TaijiFit program, a revolution in mind-body exercise. He has a B.A. in Human Movement Studies from San Francisco State University, completed graduate course work in physical education and Chinese, and participated in a program to study healthy aging at the University of Saskatchewan. ii Mr. Ross has successfully sought to modernize and mainstream the teaching methods used to transmit the ancient mind-body disciplines to contemporary students without losing the essence of those arts. Since 2012, he has collaborated with international action film star Jet Li on a mission to introduce tai chi to 100 million new people worldwide by the year 2020. Mr. Ross has been a fitness industry leader for more than 30 years. He was the founder and chief instructor of the Honolulu T’ai Chi Academy and a certified continuing educator for the American Council on Exercise. He is recognized as an expert on mind-body fitness in particular but also on fitness in general. He has been a presenter at virtually every major fitness conference in the United States, Canada, and China and has served as a committee member for several organizations, including the National Association of Health and Fitness. Mr. Ross’s competitive performances have won him seven U.S. gold medals, two world bronze medals, and a world silver medal— the highest awards ever given to an American for international tai chi performance. His tai chi training includes studying in China with the coach of the women’s world tai chi champion and with Wu Bin, the former head coach of the Chinese national martial arts team. In the United States, Mr. Ross’s teachers include Grandmaster Doc-Fai Wong and Master Wen-Mei Yu, and for the past 10 years, he has been the student of Master Wei Jingling. Mr. Ross is the creator of a dozen award-winning DVDs, including T’ai Chi Beginning Practice (the number-one selling tai chi video in America), produced by Gaiam. He also hosted the PBS television special T’ai Chi: Health and Happiness. His first show on PBS was T’ai Chi in Paradise. He is the author of five books on health and wellness, including Exercising the Soul, an Amazon number-one best seller in the meditation category. Professor Biography Martial Arts for Your Mind and Body iii Mr. Ross’s company, TaijiFit, aims to combine the best of traditional tai chi with modern Western fitness for health and happiness. His list of clients includes UnitedHealthcare (on the corporate fitness side). In 2011, when LA Fitness bought Bally Total Fitness, Mr. Ross was hired to recertify more than 1,000 LA Fitness personal trainers. Mr. Ross is a pioneer in the use of social media and the Internet to teach tai chi, qigong, and meditation. He created the first online full-service mind-body training studio at daviddorianross.com, with all classes at the studio held in real time via two-way video. The curriculum’s centerpiece is the TaijiFit program, but it also includes yoga as well as Nia (neuromuscular integrative action) and classical tai chi (taijiquan). Mr. Ross’s other Great Courses are Essentials of Tai Chi and Qigong and Mastering Tai Chi. ■ iv TABLE OF CONTENTS INTRODUCTION Professor Biography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Disclaimer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii Course Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 LESSON GUIDES LESSON 1 Strengthen Your Mind, Balance Your Body. . . . . . . . . . . . . . . . . 2 LESSONS 2–4 Karate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 LESSONS 5 AND 14 Tai Chi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 The chapters of this guidebook are organized by martial art; for example, the second chapter covers karate (video lessons 2 through 4), while the third chapter covers tai chi (video lessons 5 and 14). The guidebook chapters supplement their corresponding video lessons by providing information like historical background, useful exercises, and recaps of certain movements. Martial Arts for Your Mind and Body v LESSONS 6–8 Tae Kwon Do. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 LESSON 9 Qigong. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 LESSONS 10–13 Kung Fu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 LESSONS 15–16 Judo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 LESSON 17 Jujitsu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 LESSONS 18–20 Muay Thai. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 LESSONS 21–22 Jeet Kune Do. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 LESSONS 23–25 Krav Maga. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 SUPPLEMENTAL MATERIAL Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Image Credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 vi DISCLAIMER T his series of lectures is intended to convey general health, fitness, and self-defense principles and is for educational purposes only. These lectures include demonstrations in the field of martial arts, performed by experienced professionals. They are not a substitute for, nor do they replace, professional medical advice, diagnosis or treatment of health conditions, or other specialized training. Please consult your physician or other health-care professional before beginning or changing any fitness or exercise program to make sure that it is appropriate for your needs. If you have any concerns or questions about your health, you should always consult a physician or other health-care professional. Do not disregard, avoid, or delay obtaining medical or health-related advice from your health-care professional because of something you may have seen or heard in these lectures. Current health and fitness research may exist that could affect the educational information provided in these lectures, and advice found herein may not be based on the most recent findings or developments. Therefore, the use of any information provided in these lectures is solely at your own risk. By continuing with the programs, exercises, advice, information, or diets discussed in these lectures, you recognize that there are risks of injury or illness that can occur because of your use of the aforementioned information, and you expressly assume such risks and waive, relinquish, and release any claim that you may have against The Teaching Company as a result of any future physical injury or illness incurred in connection with, or as a result of, use or misuse of the programs, exercises, advice, diets, Martial Arts for Your Mind and Body vii and/or information discussed in these lectures. The opinions and positions provided in these lectures reflect the opinions and positions of the relevant lecturer and do not necessarily reflect the opinions or positions of The Teaching Company or its affiliates. The Teaching Company expressly DISCLAIMS LIABILITY for any DIRECT, INDIRECT, INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOST PROFITS that result directly or indirectly from the use of these lectures. In states that do not allow some or all of the above limitations of liability, liability shall be limited to the greatest extent allowed by law. ■ viii ACKNOWLEDGMENTS A note from David-Dorian Ross: The martial arts have been a part of my life for 40 years. They have been much more than a health and fitness pursuit, and much more than a vocation. They have shaped the course of my life and made me the person I am. They have also introduced me to some of the best friends a person could ever hope to know: people of great character, loyalty, honesty, and accomplishments. No one person could ever be an expert in every martial arts style, so when I began this project, I knew we would need to bring in guest instructors of high caliber. These are people I am proud to call friends and to whom I extend my greatest thanks. It was an honor—and a sheer delight—to work with them on this course. This course’s guest instructors include the following people, who lent their expertise in particular styles of martial arts: Helana Cauliffe, representing jeet kune do. Johnny Chang, representing white crane kung fu. Akira Fukuda, representing karate, judo, and jujitsu. Joshua Grant, representing praying mantis kung fu. Kathy Long, representing Muay Thai. Tammy McKracken, representing Krav Maga. Dave Wheaton, representing tae kwon do. ■ 1 MARTIAL ARTS FOR YOUR MIND AND BODY T he phrase martial arts suggests skills of combat raised to the level of an art. But throughout history, martial arts have been much more than systems and styles of fighting. They have also been systems and styles of personal growth, developing the mind and character along with the body. They are systems of philosophy that are active rather than academic and demonstrable rather than rhetorical. For the masters of the martial arts, there is a clear distinction between being a fighter and being a martial artist. Even if you’re undefeated by any opponent, if you do not defeat your own ego and tame your baser impulses, you are merely a brawler. As this course shows, almost every martial art is as much about discipline for the mind as it is for the body. A true history of the martial arts may extend to the beginning of civilization itself, when warriors trained for battle for the conquest of kingdoms or for the survival of a tribe. But this course focuses on the brief histories of the martial arts styles well known and available in the 21st century. The course begins with the Chinese martial art known as Shaolin Kung-fu, which traces its origins to the 5th century AD. It comes full circle to cover a kind of martial arts so new that it has not yet formalized itself as style: Krav Maga. ■ SCOPE 2 LESSON 1 STRENGTHEN YOUR MIND, BALANCE YOUR BODY Martial Arts for Your Mind and Body 3 E very martial arts style is different. But certain features are somewhat common to all martial arts style. After all, a punch is basically a punch no matter the style. And a kick is a kick— although in this course, we will see the nuances, details, and slight differences between different styles. This lesson introduces a few basic ideas and techniques that will be useful for the lessons to come. Note: Even if you are in good health and have been a regular exerciser, you should practice caution when learning a martial art. It is advisable to consult with your physician about your readiness to try a martial art. STANCES This section recaps two positions from the video lesson: the lunge and the horse riding stance. Lunge Stance One of the most basic positions in many martial arts styles is the lunge stance. The left foot comes in front, with the front knee bent. The back leg should be fairly straight. Note: Some martial arts styles require more extension and straightness in the back leg. Other martial arts styles will go the opposite direction and ask you for some softness in the back leg and knee. This lesson focuses on a generic approach in between. Your weight should be distributed about 60 percent over the front foot and 40 percent over the back foot. Be careful, because you might find yourself with your back heel off of the ground, or you might find your knee coming far forward. In this particular lunge, you want both feet firmly on the ground. The front toe should be pointing forward and the back toe should be turned out about 45 degrees. 4 Lesson 1 ◆ Strengthen Your Mind, Balance Your Body After you’ve completed the lunge with the left foot in front, switch legs. Horse Riding Stance The horse riding stance is a wide straddle position that requires you to sit down as though riding a horse. Stand with your feet together and the toes pointing forward. Next, use this method to get your feet double shoulder-width apart: With the weight on your heels, pivot your toes outward 45 degrees. Then, pivoting on your toes, turn the heels out 45 degrees. Switching to pivot on the heels once more, turn the toes out 45 degrees again. Finally, pivoting on the toes, turn the heels straight. That should leave the feet approximately double shoulder-width apart. Now, sit down like you’re sitting in a chair; the back should end up straight. A common mistake at this point is feeling like your back is straight when you’re actually leaning backward slightly. Check Lunge Stance Martial Arts for Your Mind and Body 5 for that, and if it’s happening, pull your hips in. This will make your rear go out slightly more, straightening your back in the process. You should feel stable at this point. If you sit down and feel like your feet want to turn out slightly, don’t fight it, especially when you’re first learning this. This stance puts a bit of torsion on the knee, and all training should be done with safety as the first priority. EXERCISES This section recaps three moves: the heel front kick, the roundhouse kick, and the basic punch. Heel Front Kick To begin the heel front kick, face a target that you can kick over—a small stool, for example. Lift one knee and point it at the stool to aim your kick. Slowly extend the leg over the top of your stool, with the toes pulled back so that the heel is extended. As you extend the leg, also push your hips forward. Finish by slowly Horse Riding Stance 6 Lesson 1 ◆ Strengthen Your Mind, Balance Your Body bending the knee again, straightening up your hips, and placing your foot on the floor again. Repeat 5–10 times, then switch to the other side. Roundhouse Kick To begin the roundhouse kick, stand next to a table that is about hip high to you. Pivot on the outside foot until it faces 135 degrees away from where you are facing. Lift your knee and place the full length of your shin and lower leg on the table. Notice that you will have turned your leg 90 degrees. Now slide your leg out and in to mimic the kicking motion. Basic Punch Start the basic punch by making a proper fist. Extend all the fingers and thumb, and then tightly curl the fingers into the palm of your hand. Roll them down until the knuckles fold over, and then lock them against the palm by folding the thumb across the lower part of the knuckles and squeezing into the hand. Martial Arts for Your Mind and Body 7 Now, extend the whole arm into the final punch position. In this position, be sure to focus the impact area on the first two knuckles (belonging to the index and middle fingers). Make sure that the wrist is bent at a slight downward angle. Practice punching in air, slowly at first and progressing to threequarters speed. Avoid full-speed punching, as that makes it easy to hyperextend the elbow joint. Punch in increments of 10, increasing as your stamina improves. Suggested Reading Cochran, Complete Conditioning for Martial Arts. Delp, Fitness for Full-Contact Fighters. Lawler, Martial Arts for Dummies. 8 LESSONS 2–4 KARATE Martial Arts for Your Mind and Body 9 Karate focuses on punching, kicking, attacks with the knees and elbows, chops and spears with the open palm, joint locks, grappling, and throwing. Each technique is powerful and direct. BACKGROUND ON KARATE Karate is originally from the Ryukyu Islands of southern Japan, in particular the island of Okinawa. Although they are now considered to be part of Japan, for centuries the Ryukyu Islands were a separate country. During this time it carried on extensive maritime trade with both China and Japan. To protect the king, a secret cadre of bureaucrats and advisers were trained in martial arts. Certain individuals studied an art that originally was simply called te, meaning “hand.” Because it was heavily influenced by Chinese martial arts, it was called kara (meaning “Chinese”) te, or “Chinese hand” in full. In 1922, Gichin Funakoshi—modern karate’s most ardent promoter—changed the character used for the sound /kara/. Now instead of “Chinese hand,” the Japanese version reads “empty hand.” Many martial art historians believe that the basis of this martial art was a form of Shaolin kung fu from Fujian province. STANCES This segment recaps two stances: the natural stance and the front stance. Natural Stance In the natural stance, your feet should about shoulder-width apart. They should be at a comfortable width, so if you need to go 10 Lessons 2–4 ◆ Karate slightly wider than shoulder-width, then do so. Make two fists and tuck the elbows into the body. Front Stance To enter the front stance, step forward with one leg. The front leg should be bent and the back leg should be straight. Refer to the Front Stance Natural Stance Martial Arts for Your Mind and Body 11 video for a demonstration of how to find the proper dimensions of the stance. EXERCISES This section covers three karate-related exercises: mokuso, a recap on making fists properly, and fist pushups. Mokuso In traditional karate classes, the sessions end with mokuso, which means “meditation.” This is usually a simple seated meditation that focuses on breathing. This meditation is meant to help with calm and clarity of mind. Take 10 minutes and sit, either crosslegged or kneeling. Focus on slowing the breath and tuning out everything else. Making Fists It’s important to practice making fists. Do this one hand at a time: Fully extend all the fingers of your hand and then tightly draw your fingertips to the top of your palm. The higher up on your palm you can touch, the better. From there, roll your knuckles over and fold the thumb over the space between the first and second finger joint, then squeeze hard like a vice. Do this five times in a row and then switch to the other hand. Fist Pushups An effective punch has the weight of the body behind it; otherwise, it lands like a feather rather than a hammer. But if you’re not prepared for what that feels like, you may wind up hurting your hand more than you hurt your target. 12 Lessons 2–4 ◆ Karate Some people train to improve their punches by doing pushups on their fists. To level up to this, start with both knees down and one palm open. In this way, you are only putting pressure on one fist at a time. Note: Remember that the point of impact is supposed to be the first two knuckles. Suggested Reading Funakoshi, Karate-Do. Funakoshi and Teramoto, The Twenty Guiding Principles of Karate. Grant, Walking in the Footsteps of the Master. Jennings, Pragmatic Karate. Nagamine, The Essence of Okinawan Karate-Do. Questions to Consider 1. One of the most important principles in karate is that there is no first strike. This is a principle of non-aggression and of restraint. Restraint is a skill that must be practiced. How would you go about practicing restraint? 2. Karate, which was originally from Okinawa, has evolved to incorporate a Japanese concept known as the code of Bushido, or the code of the samurai. This code contains seven important virtues: benevolence, courage, honesty, honor, loyalty, respect, and rectitude. Which of these do you resonate with the most? Which do you feel you lack? 13 LESSONS 5 AND 14 TAI CHI 14 Lessons 5 and 14 ◆ Tai Chi T his course introduces many martial art styles that are fast, strong, and intense. However, not all martial arts are like that. Tai chi, in fact, is known for its softness and slowness. But how does tai chi function as a martial art when the movements are done so slowly? To answer that question, you will need to understand a fundamental principle in tai chi: softness overcomes hardness. HISTORY OF TAI CHI Although tai chi has roots that go back millennia, tai chi as we know it today began in the 17th century in the Chinese village of Chen. There, in the years around 1645–1660, a man named Chen Wangting instituted a number of sweeping changes to his family’s martial art style. He instituted theories of leading and guiding energy flow through the body by means of specific motions and breathing pattern. He reorganized and consolidated the many practice routines into seven sets: five shorter exercises, a 108-movement long form, and an explosive routine called cannon fist. He also introduced a new method of training for sensitivity and fighting awareness called tai shou, or “pushing the hands.” UNDERLYING PRECEPTS China has a long history of violence, invasion, and civil war. Consequently, of the records of many historical periods have been lost. However, one theory about Chen Wangting says that he was influenced by his journeys to a local temple that blended the three main philosophies of China: Taoism, Confucianism, and Buddhism. Each of these different philosophies has a core belief. Martial Arts for Your Mind and Body 15 For example, in Taoism the core belief is known as ziran, which means to follow the way of nature. More specifically, it means to follow your own personal nature. In English the best word to describe this would be “authenticity.” The core belief of Confucianism is benevolence. According to this belief, the responsibility of those in power (like emperors) is to take care of their subjects the way a parent takes care of their children. And the core belief of Buddhism is compassion for all living things. The philosophy of tai chi can be encapsulated as the blending of these three essential philosophies: authenticity, benevolence, and compassion. Tai chi is known as an internal martial art; the meaning of this is twofold. On the one hand, internal means attention to the inner energy known as qi. The movements of tai chi must be done in such a way so that that the qi can circulate in a free and harmonious manner. Internal also means that your inner self, or character, is constantly improved as you learn more and more about tai chi. This is known as the cultivation of energy. TRAINING TIPS Tai chi operates on a set of principles. Principles are articulated in the traditional writings about tai chi known as the tai chi classics. There are more than 20 different principles, which are supposed to guide the proper method of tai chi practice. But for the beginner, following all these principles can be overwhelming. Therefore, it’s advisable to focus on only one principle at a time. The most important principle for learning tai chi is the principle of flow. Flow is the characteristic that distinguishes tai chi apart from any other form of martial arts or exercise. Flow is movement that is harmonious, synergistic, and continuous. Flow is external, meaning how the physical body moves. Flow is also internal, meaning how the qi energy is moving. 16 Lessons 5 and 14 ◆ Tai Chi Flow is disrupted wherever there is tension, either physical or mental. Therefore, when you’re beginning to practice flow, allow yourself to be terrible. In other words, don’t worry about whether you’re doing it correctly or incorrectly. Just focus on obtaining a pleasant feeling. There will be plenty of time later to refine your movements, but you will always practice more consistently if you enjoy the activity. STANCE: STANDING LIKE A TREE The practice of standing meditation is important in tai chi. It involves a certain kind of posture so that the internal energy (qi) can move freely and harmoniously throughout the body. In turn, this gives the body strength and power for martial techniques. A good place to start learning about standing meditation is with a posture called standing like a tree. To enter this stance, stand with your feet about shoulder-width apart and your knees and hips slightly relaxed. Also relax the neck Standing like a Tree Martial Arts for Your Mind and Body 17 and waist. Then, raise your hands up and around in front of you, as if you’re hugging a tree. The toes should be pointed straight forward, though it’s OK to turn them slightly if that’s more comfortable. The upper body should also be relaxed. The circle you’re making with your hands will draw your chest into a bit of a hollow. The head floats up; think of yourself looking down your nose at some point in the distance. If you keep your neck straight and then look down your nose, it will straighten out the back of your head. The tip of the tongue should come to the roof of the mouth, lightly touching the upper palate just behind the teeth. It will stay there during the course of your standing meditation. EXERCISES 1. Try going through your day holding your head in the tai chi alignment. Do you notice new things you hadn’t noticed before? Do you notice that familiar things look new? 2. Instead of a coffee break, try a break where you sink the qi. (Refer to the Lesson 5 video for a demonstration.) 3. Walk across the room using the basic tai chi stepping method. Wait to move the back foot until there is absolutely no weight left on it. When you step out in front, gently place the heel down with no weight as well. 18 Lessons 5 and 14 ◆ Tai Chi Suggested Reading Barrett, Taijiquan Through the Western Gate. Davis, Taijiquan Classics. Huang, Embrace Tiger, Return to Mountain. Olson, tr., The Intrinsic Energies of T’ai Chi Ch’uan. Read, The Manual of Bean Curd Boxing. Question to Consider 1. The Chinese word yi usually translates to English as “intention,” but it means much more than the typical English meaning. Yi is a highly focused desire for a specific outcome, brought about by the influence of qi energy. If you could use your qi to create any outcome, what would it be? 19 LESSONS 6–8 TAE KWON DO 20 Lessons 6–8 ◆ Tae Kwon Do T ae kwon do—the world’s most popular and commercially successful combat sport—is barely 60 years old, although its roots go back hundreds of years. It is known for its lightning-fast, head-high kicking style, but there is much more to it than that. In the 1988 Olympic Games in Seoul, tae kwon do was added as a demonstration sport. It became an official event at the 2000 Olympic Games in Sydney, Australia, making it only the second martial art to gain Olympic event status. ABOUT TAE KWON DO Tae kwon do’s primary stances are the horse stance and front lunges. Hand techniques include straight punches, chops, knifeedge palms, inward and outward blocks, and upper and lower blocks. Tae kwon do uniforms bear a striking similarity to those of karate. The standard uniform of tae kwon do is known as a dobok, which is tied around the waist with a belt known as a dhee. As in judo and karate, different color belts designate the different levels of achievement. Generally, darker colors denote higher ranks, culminating in black. Once a student has attained the black belt, they proceed through a series of dans, or levels, from 1st to 10th. The curriculum of most tae kwon do schools includes the practice of forms, called Poomsae; sparring, called Gyeorugi; and breaking, meaning using the hands and feet to break boards or bricks to demonstrate focus, speed, and power. HISTORY OF TAE KWON DO During the Japanese invasion and occupation of Korea from 1910– 1945, Korean martial arts were forbidden. But after World War II and the liberation of Korea in 1945, traditional Korean martial arts were once again allowed. Martial Arts for Your Mind and Body 21 In 1952, the president of South Korea asked the five main martial arts schools to come up with a plan to combine and consolidate what they had all been teaching into a unified system. Initially, this system was called tae soo do, or the “way of the hand and foot.” But one of the leaders of this unification project, General Choi Hong Hi, advocated that the name be changed to tae kwon do, because while soo means “open hand,” kwon means “fist.” Thus, tae kwon do means the “way of the foot or fist” or possibly the “way of the kick and punch.” In ancient times, the rulers of Korea were protected by an elite group of warriors known as the Hwarang. When General Choi was formulating the system that became tae kwon do, he chose the code of the Hwarang as the credo for this new martial art. It is based on five tenets: courtesy, integrity, perseverance, selfcontrol, and indomitable spirit. KICKS Tae kwon do emphasizes several types of kicks. Among them are the front, side, and roundhouse kicks. The front kick is a good kick Front Kick 22 Lessons 6–8 ◆ Tae Kwon Do for the beginning of a training session. It’s relatively simple and warms up the leg muscles. The side kick involves bending the knee, chambering the kick, opening the hip, and then pushing the kick out. (Chambering means to bring the limb into a preparatory position.) The roundhouse kick is more difficult and relies on the coordination of hip and foot movement to generate power. The oblique muscle is the primary stabilizer for this kick. Roundhouse kicks strike with the instep. Refer to the Lesson 11 video for demonstrations of these kicks. EXERCISES A beginner should practice these three techniques consistently: basic kicks, bouncing on your toes, and the kihap (yelling). This may sound like an odd list, but these are the three things that most beginners have little experience with. Side Kick Martial Arts for Your Mind and Body 23 Bouncing Part of the style of tae kwon do is a rhythm of bouncing on the toes. However, as soon as a new white belt begins to practice bouncing, they quickly discover how tiring it can be. It’s not all that different from skipping rope. Set a timer to bounce on the toes in 30-second intervals. Also try bouncing in a large circle entirely to your left and then in the reverse direction. When you feel comfortable with the time increment that you’re using, add another 30 seconds. Yelling The kihap is a loud cry that expels the breath forcefully and gives emotional intensity to your kicks and punches. The kihap is a very personal sound; in other words, everyone’s kihap is a little different. Nevertheless, it is an integral part of tae kwon do training, so it’s a good idea to get used to it and develop your own personal sound. Roundhouse Kick 24 Lessons 6–8 ◆ Tae Kwon Do Watch a few videos of black belts demonstrating tae kwon do technique to hear what their kihap sounds like. Then, play around with making a similar sound until you find one that feels natural to you. Practice making your kihap sound with a series of punches. Kicking Standing on one foot and holding onto a chair or the wall, lift one knee up and point it at a particular point in space. This will be your imaginary target. Begin by slowly simply straightening out the lower leg, then bending it again 10 times a row. Then, switch feet and repeat. After a while, you can begin to increase the number of repetitions from 10 to 20 and so on. Suggested Reading Chun, Taekwondo Spirit and Practice. Cook, Taekwondo. Kim, Complete Taekwondo Poomsae. Park, Tae Kwon Do. Savoie, Taekwondo. Questions to Consider 1. There are five different tenets of the tae kwon do creed (adapted from the ancient Hwarang code): courtesy, integrity, perseverance, self-control, and indomitable spirit. Among those, indomitable spirit is considered to be the most important. Why do think that is? 2. According to the Kukkiwon—the central authority for tae kwon do in Seoul, South Korea—tae kwon do is classified as a combat sport. What do you think is the difference between a combat sport and a martial art? 25 LESSON 9 QIGONG 26 Lesson 9 ◆ Qigong Qi is the Chinese word for the energy of life, and the ability to manipulate qi is at the heart of a great many Asian martial arts. The science of understanding the flow of qi and what it does is called qigong, which can be translated “working the qi” or even “meritorious energy.” Qigong is a category of systems and styles of energy work, rather than a distinct style. It’s an umbrella term, and under it you will find scores of other distinct styles and routines. There are many different qigong routines, all for the basic purpose of purifying and harnessing the power of the inner life force. BACKGROUND ON QIGONG One of the oldest forms of qigong that is still practiced today is called dance of the five animals. It was designed and taught by the famous Chinese physician Hua Tuo, who lived during the Warring States period. It is a noteworthy form of qigong because instead of following all the rules of posture and breath supposedly essential for human circulation, it teaches you how to shape your body like the animal: breathing as they breathe and moving as they move. Since all life is based on the harmonious flow of qi energy, then the benefits of qigong can be said to affect all of one’s life. But here are some particular benefits of qigong practice recognized by tradition: ‹ It helps to develop the skill of intention. ‹ It strengthens the physical body. ‹ It teaches you to connect to your opponent on an energetic level. ‹ It helps you cultivate wu de, or martial virtue. ‹ It opens the door to connecting with the Tao (the natural universe). Martial Arts for Your Mind and Body 27 UNDERLYING PRECEPTS Qigong can be divided into three broad categories: medical qigong, martial qigong, and spiritual qigong. Note: They often overlap. Medical qigong is likely the oldest category. For centuries, Chinese healers have developed a system of medicine based on the theory of qi as a life force. All illnesses—including mental illnesses— are considered to be some kind of problem with the circulation of qi in the body or the quality of qi in the environment. But in the traditional approach to health, the best method was to be proactive and prevent disease rather than trying to cure it. In fact, in ancient times, the village healer only received payment as long as his patients stayed healthy. They forfeited their fees if the patient became sick. To that end, there has developed a whole category of gentle exercises that are done to promote optimal cultivation and circulation of the qi. These are typically referred to as meditations, and they include routines like the five animal frolic and the eight sections of silk. Spiritual qigong is practiced for the purpose of achieving enlightenment and, in some cases, immortality. Much like the medieval European alchemists who searched for the Philosopher’s Stone, Chinese philosophers also pursued the so-called pearl of immortality. Although some of these alchemists took the concept of immortality literally, for most others it was seen as a metaphor for attaining a state of consciousness in harmony with the universe. Martial qigong is made up of special breathing and visualization exercises for the purpose of increasing martial prowess. For example, according to qigong theory, qi can protect the body from damage when struck by punches and kicks. By the same token, channeling qi into kicks and punches will make them much more devastating. 28 Lesson 9 ◆ Qigong MEDITATION According to qigong theory, each time the qi completes a circuit through the body while under meditative conditions, it refines its essence. As the qi refines itself, it transforms into a new kind of energy known as shen, which translates to “spirit.” An example of spiritual qigong meditation would be the microcosmic orbit meditation. But it’s also a case where the three categories of qigong practice overlap: The microcosmic orbit would also be Martial Arts for Your Mind and Body 29 taught to students of both medical and martial qigong because it teaches the main pathways of qi flow. Essentially, the microcosmic orbit is the circulation of the qi up and down the spine. According to this theory, there are two major channels, or meridians, through which the qi flows in the microcosmic orbit. The first one is called the Ren channel, which guides the qi down the front of the spine. This meridian starts under the lower lip and continues all the way to the perineum. At the perineum, the Ren finishes and the Du channel begins. It proceeds up the spine, over the top of the head, continues down across the forehead, and ends just above the upper lip. Along both channels, major acupoints serve as gates or valves that regulate the flow of qi through the orbit. These points correspond to the chakras in yogic meditation. TRAINING TIP There are four ideas to keep in mind during qigong practice: alignment, breath, relaxation, and visualization. These four components are thought to impact the ability of the qi to flow harmoniously and synergistically in the body, and create health and longevity. A fundamental principle to improving in martial training is this: We get better at what we practice most, and we get worse at what we practice least. The trick is to begin accumulating as much practice time as you can around those four components, but let yourself do it a little at a time, even if it is just 5 or 10 minutes at a stretch. 30 Lesson 9 ◆ Qigong Suggested Reading Janke, The Healing Promise of Qi. Li, Kung Fu Scholar Methods. Liang and Wu, Qigong Empowerment. Yang, Qigong, The Secret of Youth. 31 LESSONS 10–13 KUNG FU 32 Lessons 10–13 ◆ Kung Fu T his section of the course introduces kung fu, a martial art that either directly or indirectly influenced almost all the martial arts of China. Chinese martial arts, in turn, traveled abroad and formed the foundation of the martial arts found throughout Asia. In both style and technique, we see echoes of kung fu in almost every martial art covered in this course. Kung fu establishes a spiritual connection to the practice of martial arts. This shows up in the other martial arts as codes of honor, mental disciplines, and martial stoicism. THE SHAOLIN TEMPLE The history of the Shaolin Temple—vital to the development of kung fu—is part of the story of the migration of Buddhism from India and Tibet into China, and from there to the rest of the world. In about 465 AD, a monk named Buddhabhadra came to China on a mission to teach Buddhist philosophy and especially Buddhist meditation. Buddhabhadra developed favor with the emperor and was granted land in southern China. There, Buddhabhadra built a temple called Shaolin. Shaolin Temple Martial Arts for Your Mind and Body 33 Thirty years later, another Indian monk arrived in China. His name was Bodhidharma. Eventually he made his way to the Shaolin Temple and brought a new angle on the Buddhism studied there. This new approach placed little emphasis on studying the sutras (the sacred writings) or on the wordy explanations of the nature of the universe to achieve enlightenment. Instead, enlightenment is sought through direct experience of the body, the mind, and the emotions. In particular, the Shaolin method was to achieve these direct experiences through the practice of martial arts. But along the way to mastering fighting skill, it is equally important to develop one’s character. This is done through the devotion to wu de, or martial virtue, which in turn is learned through wu gong, or martial merit. That’s a code of moral precepts appropriate for the martial artist. They include (among others) humility, respect, righteousness, trust, and loyalty. These are known as the obligations of the mind. Accompanying those are obligations of deed: will, endurance, perseverance, patience, and courage. This is the key to understanding true Shaolin kung fu: Great fighting skill without martial virtue only makes one a brawler and a bully. But those who wish to find the strength to persevere to enlightenment will develop that strength through martial training. WHITE CRANE KUNG FU Perhaps no other country in the world has a martial history as diverse as China does. There are hundreds of styles of martial arts in China, influenced by animals, elements of nature, and mythical heroes and warriors. Many of these martial arts made their way 34 Lessons 10–13 ◆ Kung Fu into the Shaolin Temple as ex-soldiers and fighters joined the temple and brought their martial arts specialties with them. From time to time, these martial styles left the temple and then became schools that grew up in local areas within China. One such example is white crane kung fu. White crane is characterized by these traits: 1. A special kind of hand formation known as the crane fist. 2. Defensive postures that mimic the way the crane stands and moves. 3. A theory that the crane style conserves and develops something called jing—a special type of life essence that contributes to both health and longevity. White crane kung fu is not always performed fast or powerfully. It can be done slow or fast. In fact, the ancient writings about this martial art say that sometimes it should be soft and sometimes it should be powerful. Depending upon the situation, the practitioner gets to choose whether it’s slow or fast, soft or powerful. TRAINING TIPS Flexibility training is extremely important for kung fu. There are two types of flexibility important for Chinese martial arts: static and dynamic. For static stretches, yoga is the best method. Yoga has stretches for just about every part of the body in every range of motion. However, you don’t need to spend hours and hours in yoga practice. You can develop your own short yoga sequences to meet your needs for martial arts. Martial Arts for Your Mind and Body 35 Dynamic stretches are light kicks and punches. It’s important to let your body practice moving in the same way that it will when kicking or punching at full speed. However, these dynamic stretches should be done at very slow speeds without putting too much power behind them. EXERCISES This section introduces three exercises: a dynamic front stretch, the crescent kick, and straight punches. Dynamic Front Stretch Stand with your feet together and your arms stretched out to either side. Flex both wrists so that your fingers are pointing straight up, and then tuck the thumbs into the palm. Starting with the right leg, lightly kick forward as if your toes would eventually touch your forehead. Be careful: Don’t kick too fast or hard. Keep this a light stretch. As you practice this kick, keep your arms extended to either side without letting them drop, and keep your back straight without hunching forward. Perform five kicks in a row and then switch to the left foot. Crescent Kick Stand in front of a low chair or footstool with your feet together and your arms stretched out to either side. Flex both wrists so that your fingers are pointing straight up, and tuck the thumbs into the palm. Starting with the right foot, kick over the top of the chair or footstool. This means you will reach the foot across the midline of the body and kick over the top of the chair from left to right, 36 Lessons 10–13 ◆ Kung Fu ending with both feet together. Keep this kick light, easy, and low. In the above image, David-Dorian Ross demonstrates the use of a stool while the arrow demonstrates a kicking arc. Like with the front stretch, as you practice this kick, keep your arms extended to either side without letting them drop and keep your back straight without hunching forward. Perform five kicks in a row and then switch to the left foot. Straight Punches With your feet about shoulder-width apart, draw both hands in tight fists to your hips. Slowly extend the right fist out so that when the arm is straight, the fist will line up with your own chin. Keep in mind that part of the punch is the turn of the waist, hips, and shoulders. Punch again, this time with the left fist. Continue until you have punched 20 times on both sides. Crescent Kick Martial Arts for Your Mind and Body 37 STANCES This section recaps two stances used in the white crane choreography from the video lessons. The first is crane horse and the second is seven star. Crane Horse An important stance from this lesson is the crane horse stance. To enter it, place your feet about shoulder-width apart. Bring your toes in slightly and bend the knees. Seven Star The seven star stance involves turning your body. Turn on the heels; the feet should be at a 45-degree angle, both facing the same direction. Your weight should be balanced in the center 50/50. Bend and then to switch the other side, pivoting on your heels. Start with the front heel and then switch to the back heel. Make sure your back is up straight, and then switch again. Keep your knees close to each other—only about a fist’s width apart. Crane Horse Stance 38 Lessons 10–13 ◆ Kung Fu Suggested Reading Ashrafian, Warrior Origins. Olson, The Eighteen Lohan Skills. Wong, The Complete Book of Shaolin. Yan, The Shaolin Workout. Yang and Bolt, Shaolin Long Fist Kung Fu. Question for Consideration 1. In Chinese medical theory, there is a substance in the body known as jing, which translates roughly as “sexual essence.” Jing is primal vitality. It goes into the conception of new life, and it contributes to longevity. According to white crane lore, the practice helps to build up and preserve jing. Would learning that white crane kung fu might help you live longer encourage you to take up the practice? Seven Star Stance 39 LESSONS 15–16 JUDO 40 Lessons 15–16 ◆ Judo J udo is a Japanese martial art best known for its grappling, flipping, and throwing techniques. Students of this art, known as judoka, wear a thick heavy uniform known called a gi, tied around the waist by a belt. The colors of the belt indicate one’s rank among other students, implying a hierarchy of respect and obedience. For many judoka, the entire martial art can be summed up in the Japanese phrase Seiryoku-Zenyo, which translates to English as “maximum efficiency, minimum effort.” HISTORY OF JUDO The founder of judo was a man named Jigoro Kano. He organized and standardized a curriculum for teaching and set a standard for performance of skills at different levels. He began working with jujitsu, a traditional fighting style, and transformed it into judo: a way of living instead of just a way of fighting. Kano established a central school in Tokyo known as the Kodokan. There, he installed the belt system that was later adopted by Gichin Funakoshi for karate and then by other martial arts. Originally, the belt system was supposed to indicate the level of curriculum a student had studied, so that traveling judoka would be able to match levels for partner work or lessons. Judo was one of the first Asian martial arts to come to the West. A form of judo was taught to special forces servicemen during WWII. Hollywood used judo as an exotic character trait for both villains and heroes. Judo was also the first martial art to be added as an Olympic event. UNDERLYING PRECEPTS In English, the Japanese word ju means “gentle” or “pliable.” There are different layers of meaning to this word. For example, Martial Arts for Your Mind and Body 41 one meaning of gentleness is that this art does not use weapons like swords or knives. It even avoids the weapons of kicking and punching. Instead, the art focuses on responses to attacks using grappling and throws. Judoka uniform 42 Lessons 15–16 ◆ Judo Another layer of meaning to the concept of gentleness is the idea of humility. Kano made it clear in both his writings and teaching methods that a constant attitude of humility and respect was essential to mastering judo. Finally, gentleness means non-forcing or non-resistance. Meeting force with force is regarded as a losing strategy. The risk of injury or defeat is too high. Moreover, force against force is inefficient: It requires too much effort to achieve results. Instead, judo teaches to always seek solutions based on melting away in the face of an attack. This is a lesson for life’s struggles outside the dojo as well. On the martial art, Kano stated: Judo is the way to the most effective use of both physical and spiritual strength. By training you in attacks and defenses it refines your body and your soul and helps you make the spiritual essence of judo a part of your very being. In this way you are able to perfect yourself and contribute something of value to the world. This is final goal of judo discipline. TRAINING TIPS The most fundamental techniques in judo are rolls and falls. These are practiced in drills so that in the event you are tripped or thrown, you can land without injury and get right back up. The basic rolls are known as ukemi. Here are some basic tips for falling and rolling: 1. Start very slowly and lightly when first learning ukemi. Begin on your knees: The closer you are to the ground, the less likely you are to impact your neck, shoulder, or back. 2. Remember to turn your head away from the roll, almost like you’re looking over your shoulder behind you. Tuck the chin to the chest. Martial Arts for Your Mind and Body 43 3. Start with only a few rolls at a time, slowly adding more as you get more practice. Use ice if your shoulder gets sore. EXERCISES The most important exercises in judo are the ukemi (rolls) and break falls. In addition to the training tips above for ukemi, here are some break-fall exercises. Slapping the Ground Make sure you do this on a mat or soft surface. Lie on your back with both knees bent. Lift both hands off the ground above your belly and then lightly slap the floor with open palms. Make sure that the angle of your arms is downward at 45 degrees rather than straight out to the sides. Beginning Back Break Fall For this exercise, start out in a squat position with your bottom very near the floor. Sit down on the floor and roll onto your back, and as you do so slap the floor with both palms. Break Fall from Standing Begin in a standing position. Bend your knees to a squat, sit down on the floor, roll onto your back, and slap the floor with both palms. Note: Whenever you’re executing a break fall, try to keep your eyes looking at your belt. 44 Lessons 15–16 ◆ Judo Suggested Reading Daigo, White, and Kōdōkan, Kodokan Judo. Ohlenkamp, Black Belt Judo. Takagaki and Sharp, The Techniques of Judo. Takahashi, Mastering Judo. Yoffie and Kwak, Judo Strategy. Question to Consider 1. Judo was based on the older traditional fighting art of jujitsu. Ju is the Japanese word for “gentleness.” Jitsu means “method” or “system,” whereas do means “the way of.” What do you think was the reason for this change from a practical/tactical focus to a focus on philosophy? Break Fall 45 LESSON 17 JUJITSU 46 Lesson 17 ◆ Jujitsu J ujitsu translates from Japanese as “the gentle fighting art” or perhaps “the pliable fighting art,” as practitioners use their bodies like pliable reeds for fighting. The martial art does not rely on raw power. As one martial arts master put it, “All you need is patience and understanding.” MAEDA, THE GRACIES, AND JUJITSU An important early figure in the spread of jujitsu was a man named Mitsuyo Maeda. He was an undefeated Japanese martial artist, having gone head-to-head with boxers, wrestlers, and other martial arts masters. He originally was with judo founder Jigoro Kano’s cohort; however, Kano kicked Maeda out for being too aggressive in matches. At this point, Maeda has no backing from Japan, so he traveled around the world as a exhibition fighter. One of his travels brought him to Brazil to put on some demonstrations. There he met and made friends with a local businessman name Gastao Gracie. After they had been friends for some time, Gracie made a special request of Maeda: to teach his eldest son jujitsu. Maeda agreed, on the condition that whatever he taught would not be shared with non-Japanese. But the Gracie boys could not keep their martial art training a secret and began teaching each other; they eventually opened their own school. The youngest of Gastao’s sons was named Helio Gracie. He was the smallest of all the family, often described as a frail child. But when he began learning jujitsu, he found his stamina and overall health improved. Emphasizing leverage and timing, he discovered he could even the odds when it came to fighting much bigger opponents. Helio’s own son, Royce, would go on to be an extremely successful competitive fighter using this style. Martial Arts for Your Mind and Body 47 EXERCISES This section contains two exercises: the basic hip escape and the basic hip switch. Basic Hip Escape Lie on your back with one leg extended and the other bent at the knee so that the foot is flat on the floor. Bend both elbows and tuck them into your chest. Using the foot that’s flat on the floor, push and slide your hips back along the floor. Simultaneously roll onto your side. Straighten our your elbows and reach for your feet as you slide. You should wind up in a folded-over jackknife position. Roll back onto your back and repeat on the opposite side. Basic Hip Switch Lie on your back. Take your right foot and step it across the left leg. Reach as far to the left as you can. Next, slide the left leg out from under the right leg, and step the left foot across the right leg as far to the right as you can. This is called a hip switch. Repeat this switch 10 times. 48 Lesson 17 ◆ Jujitsu Suggested Reading Barlow, Jujutsu. Craig, Japanese Jiu-Jitsu. Gracie, Helio, Gracie Jiu Jitsu. Balck Belt Books, 2006 Gracie, Renzo, and Royler Gracie, Brazilian Jiu-Jitsu. Kirby, JuJitsu. 49 LESSONS 18–20 MUAY THAI 50 Lessons 18–20 ◆ Muay Thai One of the most devastating Asian fighting styles is Muay Thai. It uses elbows, forearms, knees, shins, fists, and feet as weapons. This style of fighting is a favorite among mixed martial arts (MMA) practitioners because it is the most effective fighting method for close-quarters combat. Before MMA became popular, Muay Thai was the only martial art that allowed the use of clinches, elbows, and knees. HISTORY OF MUAY THAI Muay Thai, or Thai boxing, was born in the jungles of what is now Thailand, Burma, and Laos. It was primarily used by soldiers in the armies of these kingdoms. The main martial art of this region of Southeast Asia utilized swords and long knives. However, there were also empty-hand versions that eventually evolved into Muay Thai. Thai boxing is known as the art of eight limbs because fighters use both fists and both feet as well as both elbows and both knees. This means that the style depends on close contact in order to deliver blows with the knees and elbows. Some martial art historians surmise that this style evolved because of the dense jungles in this region. The vegetation made it impossible to use long swords, spears, or the long-range kicking attacks seen in tae kwon do. Because Thai boxing is such a direct and violent style of martial arts, many people are surprised at the gentle nature of the people who practice and teach it. This section’s guest instructor, Kathy Long, says that the main philosophy of most Thai boxers is: “Can I simply be better than my opponent—today?” In other words, this is a philosophy of self-awareness and self-development. Martial Arts for Your Mind and Body 51 BASIC STANCE To enter a basic Muay Thai stance, make sure your feet have some space between them. You don’t want the feet too close, and you don’t want them in a line because you’ll tend to lose your balance that way. The left foot should be forward and the right foot should be back. Your weight should be distributed evenly between the two legs. Your hands should be up protecting your face. From here, you can practice drills. Remember to breathe out every time you strike. TYPES OF PUNCHES Muay Thai incorporates four basic types of punches. The first is the jab, which, from an orthodox stance, is thrown with the left hand. A common follow-up to the jab is the cross, which travels across the body. Thrown with the right hand, this punch takes longer Muay Thai Stance 52 Lessons 18–20 ◆ Muay Thai than a jab but generates more power. Refer to the video lessons for more footwork details during this type of punch; the foot, knee, and hip should move with the punch. Jab Cross Martial Arts for Your Mind and Body 53 Uppercuts can be thrown with either hand and involve bringing the fist in an upward motion. Like crosses, they require a pivot with the lower body to generate power. Hooks can be used on their own or as a follow-up to other strikes, like crosses. They rely on complementary foot movement to generate power; for example, the left foot needs to turn during a left hook. Uppercut Hook 54 Lessons 18–20 ◆ Muay Thai TYPES OF KICKS Lesson 18 introduced two basic types of kicks: the front (or teep) kick and the round kick. The front kick drives opponents back and is typically aimed at the stomach area. The round kick comes around from the left or right and typically aims for the leg, rib area, or head. Front Kick Round Kick Martial Arts for Your Mind and Body 55 EXERCISES Effective Muay Thai depends upon flawless basic technique. One great method of perfecting your technique is to practice the following exercises in the mirror. Always aim for your own targets in the mirror: your nose, your ribs, and your groin. 1. Drill yourself on side-to-side footwork. From your fighting stance, move your front foot to the side first, and then step with your back foot. Move three times to the side. Then return, moving your back foot first and then stepping in with your front foot. 2. Shadow box at slow-motion speed. Build up slowly. Start with the jab, then add the cross, the hook, the uppercut, and the overhand punch. Gradually increase speed, but only as long as your aim is accurate in the mirror. 3. Once you are comfortable with the basic combinations, start to add in elbows and knees. Also practice the clinch techniques introduced in the Lesson 20 video. Suggested Reading Delp, Fitness for Full-Contact Fighters. ———, Muay Thai Basics. Harvey, Mastering Muay Thai Kick-Boxing. Panyā and Pitisuk, Muay Thai. Schuyver and Villalobos, Fighting Strategies of Muay Thai. 56 Lessons 18–20 ◆ Muay Thai Question to Consider 1. Muay Thai is an almost no-holds-barred martial art. Kicking to the groin and strikes with the knees and elbows are all acceptable. However, it is considered an insult and bad practice to kick your opponent in the head, because in Thailand the head is considered the most sacred part of the body, and the foot is considered lowly and dirty. How would you show respect to an adversary? 57 LESSONS 21–22 JEET KUNE DO 58 Lessons 21–22 ◆ Jeet Kune Do P erhaps no one exemplifies the martial arts to the Western world more than Bruce Lee. He ushered in the golden age of martial arts in the late 1970s, and his legacy lives on today in the form of mixed martial arts, or MMA. Bruce Lee was the first martial artist to study multiple styles of fighting systems in order to find techniques that were most effective. He rejected the formality and style typical of Asian traditional martial arts. He instead opted for a martial style that continually changed and adapted. Today’s MMA is the modern-day version of what Bruce Lee created: jeet kune do, a mix of methods from Thai boxing, Brazilian jujitsu, kung fu, and more. HISTORY OF JEET KUNE DO Bruce Lee was born in Hong Kong in 1940, and as a young man studied a kung fu style known as Wing Chun. His teacher was a famous master named Ip Man, and Lee was his best pupil. When Lee came to the United States, he brought his Wing Chun style with him and soon began teaching classes. Martial Arts for Your Mind and Body 59 In the wide-open environment of the United States in the 1960s, Bruce Lee began to expand his study of martial arts to encompass other styles. He even used styles that had not been used as actual combat arts for centuries, like Western fencing. After a time, a new style began to emerge. More accurately, a new approach to fighting emerged, because Bruce Lee was adamant that his new system was not a style at all. He called it jeet kune do, or “the way of the intercepting fist.” The essence of jeet kune do is captured in the motto written by Bruce Lee: “Having no way as way. Having no limitation as limitation.” TECHNIQUES: PAK SAO AND LAP SAO Two important techniques from the video lessons are pak sao and lap sao. Pak sao involves one hand pushing while the other hand strikes. For instance, in the image below, the right hand is pushing as the left hand strikes. Pak Sao: Right Hand Pushes, Left Hand Strikes 60 Lessons 21–22 ◆ Jeet Kune Do The opposite can also happen: The left hand can push while the right strikes, as in the following image. The other technique, lap sao, involves more of a pulling motion. Like pak sao, it can be done in two ways. Below is an image of the left hand pulling while the right hand strikes. Pak Sao: Right Hand Strikes, Left Hand Pushes Lap Sao: Right Hand Strikes, Left Hand Pulls Martial Arts for Your Mind and Body 61 And next up is an image of the opposite configuration: The right hand pulls while the left hand strikes. EXERCISES This section introduces two important exercises: the pendulum kick and distance drills. Pendulum Kick The pendulum kick is meant to be quick and distracting to your opponent. Kick low to the shin, knee, or groin the after an opponent’s high reaction attack. Practice shadow-kicking 10 times on each leg. Distance Drills The most important principle in Bruce Lee’s jeet kune do is being able to judge distance. You want to always stay far enough away from your opponent’s reach so they cannot hit you, but close enough to them that within one step you can hit them. Lap Sao: Right Hand Pulls, Left Hand Strikes 62 Lessons 21–22 ◆ Jeet Kune Do To practice this skill, pick a target on a wall, pole, or tree. Stand facing the target and place your fist on it. Now take one large step back and drop into your fighting stance. Start moving left to right, or around the target if you are able. Every so often, stop and quickly punch the target. You should only have to take one step. Suggested Reading Cheng, Jeet Kune Do Basics. Ip, Wing Chun Kung Fu. Lee, Jeet Kune Do. ———, The Tao of Jeet Kune Do. Seaman, Jun Fan Gung Fuo. Questions to Consider 1. Bruce Lee was trained in traditional Chinese martial arts, yet he went on to advocate “having no style as style.” Do you

La Physique du SportLa Physique du Sport Caroline Cohen To cite this version: Caroline Cohen. La Physique du Sport. Mécanique des fluides [physics.class-ph]. Ecole Polytechnique, 2014. Français. ffNNT : ff. fftel-01115322ff THESE DE DOCTORAT DE L’ECOLE POLYTECHNIQUE La Physique du Sport Caroline Cohen Soutenue le 25 septembre 2014 au LadHyX devant le jury composé de : John W. Bush Rapporteur MIT Jean-Christophe Géminard Rapporteur ENS Lyon Lydéric Bocquet Examinateur ENS Yves Couder Examinateur Université Paris Diderot Guillaume Laffaye Examinateur Université Paris Sud Benoit Roman Examinateur ESPCI David Quéré Directeur de thèse Ecole Polytechnique Christophe Clanet Directeur de thèse Ecole Polytechnique ii La Physique du Sport Caroline Cohen v Merci ! « Tout a une fin, sauf la banane qui en a deux. » (Proverbe Bambara) La thèse est achevée. A la joie, se mêle l’émotion de vous quitter. La thèse est un sport collectif, et la victoire revient à toute l’équipe. En quelques mots, je voudrais remercier toutes les personnes qui ont rendu ces quelques années intenses, drôles, passionnantes. Je remercie les membres du jury, chercheurs passionnés, de votre intérêt pour la Physique du Sport, de votre bienveillance et de toutes vos questions et remarques enrichissantes : Lydéric Bocquet (merci pour l’idée de rhéométrie du muscle), John W. Bush (merci de partager la passion du vin, du fromage et du foot), Yves Couder (merci pour la citation opportune de Sterne), Jean-Christophe Géminard (merci pour la lecture attentive du manuscrit), Guillaume Laffaye (merci pour toutes les discussions, toutes les rencontres improbables à la salle de muscu, au Museum d’histoire naturelle, à la Pitié...), Benoît Roman (merci de m’avoir inclus dans l’équipe des enseignements d’approfondissement Hydro et Elasticité). « L’entraîneur médiocre parle, le bon explique, le super démontre et le meilleur inspire. » (John Kessel) Christophe, merci de m’avoir entraînée dans cette aventure, à la recherche des lois, les pépites d’or du physicien. Merci de m’avoir appris à observer, à mesurer, à ne rien comprendre, et tout ça en rigolant toujours. Merci d’être un exemple de chercheur et d’humaniste. Merci pour ta disponibilité, ton humilité, ta sensibilité et ton amitié. David, merci pour toutes les histoires que tu nous racontes, et qui nous donnent envie (de rédiger un article, d’être chercheur, de faire du cirque supra ou n’importe quoi d’autre). Merci pour la note que tu apportes sur nos terrains de sport et bravo pour ton revers au ping pong. Merci à tous les deux pour votre sens physique et votre sens de l’humour. Merci d’accepter nos invitations chez vous à l’improviste, même si on est malpolis. Je n’imaginais pas de meilleurs chefs. Merci enfin d’entretenir l’équilibre (et la santé mentale) des saltimbanques de la Compagnie des interfaces, cette belle équipe où l’on vit si bien. « Le sport mesure la valeur humaine en millimètres et en centièmes de seconde. » (Bernard Arcand) Justement cette équipe, la compagnie des interfaces : je remercie les anciens d’abord d’avoir insufflé la dynamique du groupe, l’entraide et le travail collectif : Marie toujours disponible pour donner une bonne idée, Jacopo le grincheux, Keyvan l’émerveillé, Alex et ses histoires invraisemblables... les très anciens aussi, partis il y a parfois longtemps mais qui continuent à discuter avec nous en permanence : Anne, Etienne, Mathilde, José, Elise... et les post-doc : Joachim (qui n’a rien à envier à Jacopo), Cunjin (toujours prêt à ramener une TsinTao), Evan (qui a appris la coinche aussi vite que le Français). Vient ensuite la génération dorée (comme disent les chefs !) : les copains de promo avec lesquels on arrive toujours à être un multiple de quatre pour jouer à la coinche. Baptiste, nous sommes donc une banane ? Merci pour ces années de thèses où tout était facile et amusant. A deux, on n’accomplit peut-être pas deux fois plus de travail, mais c’est deux fois plus agréable, on est quatre fois plus souvent les employés du mois, on rencontre cent fois plus de gens fous vi et on rigole mille fois plus. Adri, tu es un peu plus ancien, mais au vu de tes exploits nous t’incluons dans la génération dorée... merci d’avoir partagé le quotidien du préfa (toutes les parties de bad, de foot, de coinche dans le RER, les visites sécurité...) et aussi d’avoir essayé de nous stresser, même si ça n’a jamais marché ! Pierre-Brice le funambule qui a glissé sur un brin d’herbe et s’est démis l’épaule, j’espère qu’on fera encore longtemps les mêmes choix de parcours. Guillaume, tu nous as montré qu’une pomme suffit pour faire une tarte. Merci aussi d’avoir demandé à Jean-Marc l’intérêt des développements asymptotiques ! Pascal, merci de manger lentement et faire durer les repas, pour nous permettre de discuter plus et limiter notre exposition au mercure du préfa. Puis inévitablement, les petits jeunes ont pris les commandes : Dan et Raph (à qui je dois mon style de surf), Manu (en Tshirt tout l’hiver), Philippe (le footballeur cultivé), Anaïs et Hélène (expertes du body tonic), Eline (avec qui j’aurais bien recommencé une thèse sur le surf), Timothée (l’absurdoué, ça me fait parfois peur de penser aux mêmes blagues que toi), les derniers arrivés : Martin (le combattant) et Camille, nouvelle chef (merci pour les discussions engagées et toutes tes idées), les Belges (Laurent et Martin), et enfin les renforts saisonniers de stagiaires : Eliott, Simon, Ousmane, Héloïse, Louis, Maxime, Rémi, Vianney, Anthony, Antoine, David (Michel), Nico, Carmelo (et son ballon à sécher le linge), Hadrien, Jérôme ... X Dessins de Gary Larson : l’école, le labo, le préfa. Je remercie tous les membres du LadHyX pour l’ambiance familiale qui règne au labo, qui nous donne envie de faire 2 h de RER par jour, dans un wagon bondé pour se retrouver ensemble. Merci pour les débats animés, les goûters et Tartateam à toutes saisons, les coups de gueule enflammés et les moments de rire et partage entre toutes les générations et les personnalités qui peuplent le labo. Je remercie d’abord tous ceux qui rendent notre travail possible : Caro et Antoine, pour tous les coups de mains, ou de marteau, et les astuces de bricoleurs qui nous permettent de monter nos manips de coin de table (qui souvent dépassent de la table). Merci d’avoir fabriqué la machine à frapper/casser les souvenirs (la première avec un truck de skateboard, la deuxième avec un moteur de scooter). Merci de nous rappeler qu’il ne faut pas mélanger l’eau et l’électricité, ni regarder un faisceau laser. Merci enfin de votre soutien pour le bouclage de Moving Mind, lorsque la veille, il ne bougeait toujours pas. Thérèse, Sandrine, Delphine, Caro, Judith merci d’accepter nos missions à la dernière minute (voire à celle d’après) sans nous gronder, de commander nos ballons, la piscine gonflable et le produit à bulles avec la carte bleue du labo. Dani, merci d’avoir sauvegardé le contenu de mon vii ordinateur à mon insu et ainsi sauvé la plupart de mes données. Avec Toaï et Alex, merci d’intervenir quand la machine ne veut plus rien entendre. Je remercie ensuite l’équipe de foot qui m’a permis de joindre la pratique à la théorie : Rémi (le panneau du service matériel est plié cette fois), Etienne (et ses lunettes souvent cassées), Marine (la toujours motivée), Eunok (et la reprise de volley à bout portant sur mon nez), Eline (ah non, tu n’avais pas tes affaires..), Loïc (finalement on ne saura jamais qui de nous deux gagne au bras de fer), Gaétan (le gardien volant, tu mérites bien la médaille en choco du labo), Anders, Lionel, Tom, Mathieu... et tous les anciens qui regrettent cette finale du tournoi qu’on aurait dû gagner (Jon, Juno, Cristobal, Pierre, Clément, Fabien, Diego, Franz...). Je remercie l’équipe footing, qui a réussi à me faire courir 10 km pour aller boire une bière et l’équipe salle café (où tout se décide) : Sabine (merci d’être une maman, même si tu es beaucoup trop jeune pour ça), Antoine (le sarcastique), Jean-Marc (merci de nous entraîner dans toutes tes bêtises), et l’équipe des toujours disponibles pour discuter, donner un coup de main pour une manip, pour la nuit des chercheurs ou simplement pour oser franchir la porte du préfa : Manu, Yifan, Jérémy, David, Cécile, Julie, Miguel, Nico... Merci à tous les personnels de l’Ecole Polytechnique que nous allons régulièrement embêter (Wiliam et Ali du TreX, les plombiers, les électriciens, la DSI, la Formation Sportive, le CSX, Pierre et les joueurs de bad, la Drip, la DCom, l’école doctorale...) Je remercie tous les membres du PMMH, de nous accueillir de temps en temps : Philippe, Fred et Amina pour organiser les barbecues et apéros de Noël, Eduardo pour la cuisson argentine de la viande au BBQ, Etienne pour nous apprendre à faire de la belle science, Guillaume, Xavier, Olivier, Anne pour nous laisser utiliser l’atelier, le cutter laser, l’imprimante 3D, les thésards : Nawal, David, Sophie, Bertrand... le club cuisine, les Mecawet : José toujours prêt à aller lâcher des boules de pétanques dans les calanques, Etienne à disserter sur la forme de la bulle de savon géante... « Cyclistes, fortifiez vos jambes en mangeant des oeufs mollets. » (Pierre Dac) Cette thèse n’aurait pas été possible sans tous les sportifs et entraîneurs de haut niveau que nous avons rencontrés. Nous aurions dû nous contenter de performances ridiculement faibles, les nôtres. Merci pour l’énergie dépensée sous le feu des halogènes et votre patience pendant l’acquisition des images de la caméra rapide : Michael Phomsoupha notre expert du badminton, qui a commencé une thèse avec Guillaume et a réussi à ne pas lui smasher dessus à bout portant malgré ses lunettes de chimie, tous les STAPS d’Orsay, les gardiens de foot de Juvisy et Longjumeau et leurs entraîneurs, les habitués de la salle de muscu : Gregory (qui a des bras larges comme nos cuisses), Michael, Antoine, Nouredine... Merci à tous les passionnés de sport qui nous ont aidés dans nos projets : Isabelle Jobbard, juge-arbitre de badminton, Jérôme Careil de la FFB, Catherine et Pierre Macé de Babolat Claude Boly du Musée du Sport. « Sans l’invention de la roue, les coureurs du Tour de France seraient condamnés à porter leur bicyclette sur le dos. » (Pierre Dac) Parfois les rencontres étaient plus inattendues. Le périple a débuté par le tour de France des souffleries pour faire zigzaguer les ballons. Laurent Keirsbulck nous a accueillis au LME de Valenciennes, Eric Brunel Dominique Farcy et leur équipe à l’Onéra de Lille, Fawaz Massouh et Ivan Dobrev aux Arts-et-Métiers, Thierry Faure Marc Rabaud et Frédéric Moisy au Fast, et Christophe qui nous a régulièrement prêté la soufflerie mobile pour aller faire des tours de périph à toute allure... Bruno Grandpierre, PDG de POK, nous a permis viii de mesurer la portée des jets d’eau des lances à incendie des pompiers, en vérifiant les connaissances de Guillaume sur les tuyères de Laval. Sans Jean-Pierre Gasc du Museum d’Histoire Naturelle, nous n’aurions jamais entendu parlé du microcèbe. Les LieutenantsColonnels Guyot et Briot nous ont initiés au maniement du canon Gribeauval et à son histoire, au Musée d’Artillerie de Draguignan. Renaud Beffeyte et ses servants nous ont ramené au Moyen-Age pour filmer des tirs de trébuchet, bricole et autre couillarde à la caméra rapide, au château des Baux de Provence. Patrick de Crazy Bubbles nous a aidé à faire une bulle de 3 m de diamètre au dessus de la piscine gonflable dans la chaleur moite de la salle de séminaire bleue du LadHyX fin juillet. Jean-Yves Hogrel de l’Institut de Myologie de la Pitié-Salpêtrière nous a éclairé sur les difficultés à travailller sur les maladies musculaires et nous a orienté vers le Journal of Gerontology. Merci à vous tous. « Le sport amuse les masses, leur bouffe l’esprit et les abêtit. » (Thomas Bernhard) L’organisation du colloque Euromech Physics of Sports nous a permis de rencontrer de nombreux passionnés : Marc Rabaud, Nicolas Benguigui, Alan Nathan et Wolfram Muller (qui ramènent toujours tout respectivement au baseball et au ski), Nick Linthorne (qui est venu de Londres en vélo), Metin Tolan (qui critique le foot féminin), Ross Garett (venu de Nouvelle-Zélande), Paul Dietschy, Yves Parlier, Alain Haché, François Gallaire, Antonin Eddi, Floren Colloud, Déborah Nourrit-Lucas, Nicolas Babault Philippe Brunet (avec qui nous avons passé plusieurs après-midi à lancer une balle de squash dans un coin, avant de décider de le recouvrir d’huile silicone), Pierre-Tho, Basile et Akash et tous les autres... Entre mille choses, ce colloque a été l’occasion d’apprendre à réaliser une affiche. Par decence, je vous laisse deviner qui a fait quoi... L’apprentissage de la beauté : affiches du colloques Physics of Sports par ordre de réussite croissant (ou l’inverse...) Nous avons eu la chance de participer à plusieurs conférences et l’école d’été de Thomas Bohr à Krogerup. A chaque fois, ce fut un grand plaisir de rencontrer des chercheurs passionnés de tous âges et toutes provenance. ix « Quand les mouettes suivent un chalutier, c’est qu’elles pensent qu’on va leur jeter des sardines » (Eric Cantona) Nous avons aussi eu l’occasion de rencontrer plusieurs journalistes convaincus que la physique du sport est un moyen d’aller vers les gens (Marion Solletty, David Larousserie, Annabel Benhaïm) de participer aux Nuits des Chercheurs, Fêtes de la Science, expo au Palais de la Découverte et de travailler avec des artistes (Frigo et Jimmy pour Moving Mind, Anne-Lise Le Brun pour la revue Citrus Foot). Je remercie toutes les personnes qui m’ont appris à enseigner lors du monitorat à l’X (Etienne et David en Modal, Benoît en EA, Patrick en tutorat). Je remercie Sylvain et Michael ainsi que tous les membres du MSC de m’accueillir en post-doc où je vais prendre à coeur d’améliorer ma recette de caramel. Enfin je remercie ma famille, soutien sans faille (même ceux qui disent qu’ils payent mes voyages avec leurs impôts, même ceux qui me demandent quand est-ce que j’aurais un vrai travail... mais surtout les autres quand-même.) Et les amis, que j’ai parfois fait rêver en parlant de ma thèse, mais qui me font penser à autre chose la plupart du temps : mes équipes de volley (Alex, Caro, Adèle...), de hand (Aurore, Camille, Cham...), de foot, de bad, de tennis-ballon (Greg, Juju, Fanny...) , et les coachs ! les copines de toujours : Mu Et Georgia, ceux d’après, les copains baroudeurs, la GoodHouse : Momo et toutes ses couleurs de cheveux, Lara et son amour de l’Afrique et toutes celles qui rêveraient d’en faire partie : gros chien blanc et petit chien noir, Anais... et tous les autres. Lolo, merci d’être là et de me faire rire. Merci de m’avoir dit que je n’y arriverais jamais (même si je n’ai pas tout de suite compris que c’était une blague). « L’ombre du zèbre n’a pas de rayures » (Proverbe Africain) Et pour finir, l’oeuvre du poète masqué du LadHyX : x Sourire mystérieux du chat L’armée de carte perce mon cœur L’arbalète pique ces quatre feuilles Traverse le mur Un univers remplace l’autre Spirale immobile déployée à l’infini Continents brisés du givre Mon souffle vous dévore Bleu de Tolède Je suis prisonnier de tes brouillards Je voudrais rétrécir à nouveau Echapper au temple J’ai oublié l’heure Reviens Je serai sage Table des matières I Les Sports à Records 7 1 Le muscle 13 1.1 Physiologie du muscle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.1.1 Constitution du muscle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.1.2 Contraction musculaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.2 Description phénoménologique du muscle . . . . . . . . . . . . . . . . . . . . . 19 1.2.1 Impulsion nerveuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1.2.2 Relation force-longueur . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.2.3 Relation de Hill entre force et vitesse de contraction . . . . . . . . . . 21 1.3 Modélisations du muscle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1.3.1 Modèles viscoélastiques actifs . . . . . . . . . . . . . . . . . . . . . . . . 23 1.3.2 Modèles microscopiques . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2 L’haltérophilie et les records de force 27 2.1 Expériences de développé-couché . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.1.1 Dispositif expérimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.1.2 Levée unique à vitesse maximale . . . . . . . . . . . . . . . . . . . . . . 30 2.2 Modèle de l’haltérophile articulé . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.2.1 Modélisation de l’articulation . . . . . . . . . . . . . . . . . . . . . . . . 33 2.2.2 L’haltérophile à force constante : F = 1 . . . . . . . . . . . . . . . . . . 34 2.2.3 L’haltérophile de Hill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.2.4 L’haltérophile de Deshcherevskii . . . . . . . . . . . . . . . . . . . . . . 36 2.2.5 Application à la caractérisation des muscles . . . . . . . . . . . . . . . 40 2.3 Expériences de temps de tenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.3.1 Dispositif expérimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.3.2 Résultats experimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 2.3.3 Modèle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 2.3.4 Expériences d’endurance au développé-couché . . . . . . . . . . . . . . 49 2.4 Expériences d’arraché et d’épaulé-jeté . . . . . . . . . . . . . . . . . . . . . . . 51 2.4.1 L’arraché . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 2.4.2 L’épaulé-jeté . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 3 Le muscle capillaire 57 3.1 Résultats expérimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.1.1 Dispositif expérimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.1.2 Résultats expérimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 3.2 Modèle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 3.2.1 Force élastique : F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 xi xii TABLE DES MATIÈRES 3.2.2 Force visqueuse : Fη . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 3.2.3 Relation force-vitesse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 3.3 La théorie des filaments coulissants et son analogue capillaire . . . . . . . . . 63 3.3.1 Théorie des filaments coulissants . . . . . . . . . . . . . . . . . . . . . . 63 3.3.2 Analogie capillaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 3.3.3 Interprétation microscopique de la relation de Hill . . . . . . . . . . . 65 II Les Sports de Balles : Aérodynamique et Trajectoires 69 4 Le Mur aérodynamique 73 4.1 Éléments de balistique extérieure . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.2 Résultats expérimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 4.2.1 Vitesses terminales des balles de sport . . . . . . . . . . . . . . . . . . . 78 4.2.2 Les trajectoires du badminton . . . . . . . . . . . . . . . . . . . . . . . . 80 4.3 Analyse théorique de la trajectoire . . . . . . . . . . . . . . . . . . . . . . . . . 83 4.3.1 Solutions exactes pour le tir vertical . . . . . . . . . . . . . . . . . . . . 83 4.3.2 Origine du mur aérodynamique . . . . . . . . . . . . . . . . . . . . . . . 83 4.3.3 Les deux régimes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 4.3.4 Position du mur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 4.3.5 Expression analytique de la portée . . . . . . . . . . . . . . . . . . . . . 87 4.3.6 Expression de la hauteur maximale . . . . . . . . . . . . . . . . . . . . 90 4.3.7 Angle optimal de tir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 5 Applications du mur 95 5.1 Taille des terrains de sport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 5.1.1 Portée maximale et taille des terrains de sport . . . . . . . . . . . . . . 96 5.1.2 Classification des sports de balles . . . . . . . . . . . . . . . . . . . . . . 96 5.2 L’artillerie et les champs de bataille . . . . . . . . . . . . . . . . . . . . . . . . . 100 5.2.1 Artillerie névrobalistique et trajectoires paraboliques . . . . . . . . . . 100 5.2.2 Artillerie à poudre et Tartaglia . . . . . . . . . . . . . . . . . . . . . . . 102 5.2.3 Taille des champs de bataille . . . . . . . . . . . . . . . . . . . . . . . . 102 5.3 Portée des lances à incendie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 5.4 Profondeur de plongeon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 5.5 Modification de la trajectoire avec la rotation . . . . . . . . . . . . . . . . . . . 114 5.5.1 Dégagement du gardien de football . . . . . . . . . . . . . . . . . . . . . 114 5.5.2 Equations de la trajectoire . . . . . . . . . . . . . . . . . . . . . . . . . . 116 5.5.3 Modification de la portée . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 5.5.4 Critère pour négliger le spin . . . . . . . . . . . . . . . . . . . . . . . . . 118 III Les Sports de Balles : Elasticité et Impact 123 6 Le pointu au football 127 6.1 Résultats expérimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 6.1.1 Dispositif expérimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 6.1.2 Résultats qualitatifs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 6.1.3 Résultats quantitatifs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 6.2 Modèle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 TABLE DES MATIÈRES xiii 6.2.1 Conservation de la quantité de mouvement . . . . . . . . . . . . . . . . 133 6.2.2 Expression de la force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 6.2.3 Modèle dynamique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 6.3 Frappe réelle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 6.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 7 La frappe et le lancer 141 7.1 Frapper ou lancer ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 7.1.1 Le lancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 7.1.2 La frappe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 7.1.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 7.2 Comment lancer ou frapper plus fort ? . . . . . . . . . . . . . . . . . . . . . . . 146 7.2.1 Utilisation des articulations . . . . . . . . . . . . . . . . . . . . . . . . . 146 7.2.2 Utilisation de l’énergie élastique . . . . . . . . . . . . . . . . . . . . . . 148 8 Le smash au badminton 153 8.1 Expérience de smash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 8.1.1 Dispositif expérimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 8.1.2 Résultats expérimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 8.2 Expérience à une dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 8.2.1 Dispositif expérimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 8.2.2 Résultats expérimentaux . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 8.3 Modèle harmonique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 8.4 Comparaison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 8.4.1 Excitation harmonique . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 8.4.2 Excitation triangulaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 xiv TABLE DES MATIÈRES Introduction générale Étymologiquement, la physique est l’étude philosophique de la nature. Le rôle du physicien consiste ainsi à observer son environnement, à identifier des évènements qui se répètent toujours suivant une même séquence et enfin à proposer une loi minimale permettant de comprendre la logique de cette séquence. Dans cette thèse, l’environnement est le sport et nous donnons quelques exemples d’événements pour lesquels il nous semble possible de trouver des lois. Figure 1 – La Physique du Sport, telle que nous la décrivons dans ce travail : (a) les sports à records, (b) l’aérodynamique des sports de balles, (c) l’élasticité des sports de balles et (d) les sports de glisse. Le sport, comme la nature, permet d’éveiller la curiosité des hommes. Dans son traité sur le mouvement des animaux, Aristote explique que les athlètes pourraient sauter plus loin s’ils avaient des masses dans les mains et qu’ils courent plus vite lorsqu’ils balancent 1 2 INTRODUCTION GENERALE les bras [1]. Plus tard, en 1687, Newton observe la déviation des rayons lumineux à la traversée d’un prisme et la compare aux trajectoires courbées des balles de tennis [2]. En 1850, Magnus comprend que la déviation latérale des obus de l’armée Prussienne est due à la rotation des projectiles [3]. En 1877, Rayleigh fait le lien entre l’effet Magnus et les trajectoires des balles de tennis frappées avec de la rotation [4]. A l’interface entre plusieurs sciences (physique, biophysique, biologie, sciences du sport, mathématiques), la physique du sport se nourrit d’interactions entre scientifiques, sportifs, entraîneurs, industriels du sport et permet d’aborder des thèmes très variés : aérodynamique, élasticité, friction, ondes et fluides, physique statistique, mouvement humain [5, 6]. Le sport est un « invariant culturel » : il existe depuis toujours et est universel. Pour les byzantins : « les peuples sans sport sont des peuples tristes »[7]. Le sport est caractérisé par la mise en œuvre de qualités physiques (endurance, résistance, force, coordination, adresse, souplesse...) et par l’esprit de compétition (le désir de se surpasser, de battre les records, ou simplement de gagner). Les sports sont très nombreux et il est difficile de faire une classification. On peut néanmoins distinguer plusieurs caractéristiques : est-ce que le but est de réaliser une performance (de vitesse, de précision, de force, artistique...) ou de battre un adversaire ? Est-ce un sport qui se pratique tout seul ou en équipe ? Est-ce que l’on a un objet pour jouer (un ballon à s’échanger, un objet à lancer, ou pour lancer...) ? Dans quel milieu le sport se pratique-t-il : dans l’air, dans l’eau, au sol, sur la glace ou sur l’eau ? Equipe Duel Seul Sans Avec OP T IMISAT ION ELAST ICIT E P HY SIQUE ST AT IST IQUE AERODY NAMIQUE Figure 2 – Une classification possible des sports : suivant le nombre de joueurs et l’utilisation ou non d’un instrument. La figure 2 propose une classification des sports en fonction du nombre de joueurs qui participent : un, deux ou plus et selon qu’on joue avec un projectile ou sans. Nous parcourons cette classification en pointant les sujets d’étude de la physique du sport. Sur la première ligne, on trouve les sports qui se pratiquent seul. Sans objet, l’homme n’a que son corps pour s’exprimer dans des disciplines telles que la course, le saut, l’hal- INTRODUCTION GENERALE 3 térophilie, l’escalade, la gymnastique, la natation... Avec un projectile, il s’agit de lancer le poids, le disque, le javelot, de tirer à l’arc... avec un instrument, il peut sauter à la perche, skier, surfer, naviguer, ramer... Dans la plupart des cas, l’objectif est de réaliser une performance : il sera toujours question d’optimiser une grandeur : la vitesse, la force, la hauteur, la distance, la précision, l’esthétique... Nous désignons cette première catégorie par les sports à records. Parmi ces sports, les premiers travaux ont été réalisés par Keller [8, 9] sur les records de vitesse en athlétisme. A partir d’hypothèses simples et d’une démarche variationnelle, il trouvé une loi qui décrit la stratégie optimale de course et permet de prédire les records observés sur des courses de 50 m à 2 km. La course a été le sujet de nombreuses études autant sur les courtes distances [10, 11, 12], que sur les longues distances [13, 14]. L’étude des records s’est élargie à toutes les disciplines athlétiques [15, 16, 17], et à d’autres types de courses [18]. Sur la deuxième ligne, on trouve les sports qui se pratiquent en duel : les sports de combats (lutte, judo, boxe, karaté et autres arts martiaux...) [19, 20, 21] à main nue et les sports d’opposition avec un instrument (tous les sports de raquette : tennis, tennis de table, badminton, squash...). Dans ces sports, c’est le rapport de force entre les deux adversaires qui importe. Enfin, sur la troisième ligne, on trouve les sports qui se pratiquent en équipe. Sans instrument, on trouve toutes les disciplines artistiques : natation synchronisée, danse ou les courses d’équipe comme le roller-derby. Avec un projectile, on trouve tous les sports collectifs : football, rugby, volley, baseball, handball, hockey, basket, curling, waterpolo, ultimate... Pour ces tous sports d’équipes, les mouvement collectifs et les interactions entre les joueurs et le projectile font l’objet d’analyses statistiques. La physique statistique du football est née en 1968 avec les travaux fondateurs de Reep et Benjamin et la théorie des « longues balles » 1 [22, 23, 24]. Plus tard, le sujet s’est étendu aux statistiques de buts [25, 26, 27], au nombre de passes effectuées [28] ou aux classements dans les championnats [29] et s’est ouvert à d’autres disciplines [30, 31]. En observant la classification dans l’autre sens, on distingue dans la deuxième colonne les sports pratiqués avec un objet. Si l’objet est un projectile qu’on s’échange : une balle, un ballon, un volant, un frisbee, on parlera de sports de balles et l’enjeu majeur sera l’étude des trajectoires. On cherchera à comprendre les interactions de la balle avec le milieu dans lequel elle évolue. Dans l’air de nombreuses études sont consacrées au sillage de la balle et aux effets qui en résultent : les trajectoires courbées, obtenues lorsque la balle tourne sur elle-même, observées au tennis [32, 33, 34, 35], au football [36, 37, 38, 39], au golf [40, 41, 42] ou les trajectoires flottantes obtenues lorsqu’elle est frappée sans rotation au baseball [43, 44], au football [45, 46] et au volleyball [47, 48]. Si l’objet est un instrument qui peut servir à lancer un projectile ou à propulser le corps, on s’intéresse à son élasticité. Quelles sont les déformations de l’objet et quelle énergie ces déformations permettent-elles de restituer ? De nombreuses études sont consacrées à l’impact des balles avec une raquette au tennis [49, 50, 51, 52], avec une batte au baseball [53, 54, 55, 56] ou avec le pied au football [57, 58, 59, 60, 61]. D’autres se sont intéressés à 1. Les buts sont marqués en moyenne en trois passes, sinon le ballon est perdu. Il faut envoyer le plus possible le ballon vers l’avant pour minimiser le nombre de passes à faire pour atteindre le but et augmenter les chances de marquer. 4 INTRODUCTION GENERALE l’élasticité des perches [62, 63], des arcs [64], des slacklines [65]... Enfin, parmi tous les sports de cette classification, le corps humain et ses mouvements sont l’objet d’études biomécaniques [66, 67, 68]. Lorsque le mouvement du sportif se fait dans l’eau (natation), sur l’eau (surf), sur la glace (patin à glace) ou sur la neige (ski, snowbord), nous discutons de sports de glisse. A chaque fois, il s’agit de déterminer les forces qui permettent au sportif d’avancer et celles qui résistent à son mouvement. Hayes [69] s’est penché sur la question du surf des dauphins et a déterminé les conditions d’entraînement de l’animal par la vague. Plusieurs études sont dédiées à la voile [70, 71], à l’aviron [72, 73, 74], à la nage [75, 76, 77, 78], aux déplacements sur la glace [79, 80, 81] ou sur la neige [82, 83, 84]. Dans la première partie de ce travail (figure 1-a), nous nous intéressons aux sports à records (première ligne de la classification). Nous partons de l’exemple de la course avec l’étude de Keller [8, 9] sur la stratégie optimale pour parcourir une distance donnée en un temps minimal. A chaque fois que le fonctionnement du corps est optimisé, on observe des lois générales, indépendantes de la variabilité des hommes qui réalisent la performance. Nous nous demandons ce qui fixe les records de force en haltérophilie. Quelle masse maximale un athlète peut-il soulever ? De quoi dépend cette masse ? Combien de temps peut-il soutenir une masse plus faible, ou combien de fois consécutives peut-il la soulever ? Les réponses à ces questions se trouvent dans le muscle, qui est le générateur de force ou de mouvement de l’organisme. Nous essayons de comprendre comment le muscle permet de battre les records en étudiant un geste simple de force athlétique : le développé-couché. Dans la deuxième partie de ce travail (figure 1-b), nous nous intéressons à l’aérodynamique des sports de balles (deuxième colonne de la classification). Quelles sont les trajectoires observées dans le sport ? Nous nous sommes étonnés devant les trajectoires très dissymétriques du badminton. D’où vient cette forme ? Dans quels cas la retrouve-t-on ? Nous résolvons les équations de la dynamique d’un projectile qui se déplace à grande vitesse et qui est soumis à la gravité et aux effets aérodynamiques. Une des caractéristiques de ces trajectoires est la saturation de la portée aux grandes vitesses. Nous donnons une expression analytique de la portée qui permet de comprendre la saturation. Nous nous intéressons à ses conséquences sur le jeu. Dans la troisième partie de ce travail (figure 1-c), nous nous intéressons aux impacts dans les sports de balles (deuxième colonne de la classification). Nous nous demandons comment les projectiles qui décrivent les trajectoires présentées dans la partie 2 sont projetées dans les airs. Quelles sont les lois qui régissent les impacts ? Quels sont les paramètres qui déterminent la vitesse de la balle ? Nous prenons l’exemple du pointu au football, pour savoir si la manière dont on frappe le ballon (avec la pointe ou le plat du pied) joue sur l’efficacité de la frappe. Nous étendons cette discussion aux autres sports de balles, en comparant l’efficacité de la frappe et du lancer. Nous discutons quelques moyens d’atteindre des vitesses de balle plus élevées : en utilisant une articulation ou un effet élastique. Enfin nous prenons l’exemple du smash au badminton, où la déflexion du shaft 2 de la raquette permet de frapper le volant plus fort. 2. Le shaft de la raquette de badminton est la partie qui relie le manche au tamis. INTRODUCTION GENERALE 5 6 INTRODUCTION GENERALE Première partie Les Sports à Records 7 Introduction La première catégorie de sports que nous explorons est celle des sports à records. Depuis les Jeux Olympiques Antiques, les hommes se disputent le titre de plus rapide ou de plus fort du monde dans des disciplines telles que la course, la lutte, le lancer ou encore le saut [85]. Les Jeux Olympiques modernes reposent toujours sur la volonté de battre les records : courir plus vite, soulever des masses plus grandes, sauter plus haut, lancer plus loin. Figure 3 – Les records aux Jeux Olympiques : vitesse, force, saut et lancer. Actuellement, l’homme le plus rapide du monde est le jamaïcain Usain Bolt (L0 = 1,96 m, M0 = 94 kg), il parcourt D = 100 m en T = 9,58 s. Sa vitesse moyenne est D/T = 10,4 m/s et le pic de vitesse atteint lors de sa course est 12,2 m/s. A titre de comparaison, l’animal le plus rapide est le guépard qui peut atteindre 32 m/s. Mais le guépard n’est pas endurant : il doit s’arrêter toutes les heures pour refroidir son organisme en haletant, alors que l’homme (qui a perdu ses poils au cours de l’évolution) transpire pour abaisser sa température. L’homme est donc plus endurant, certains sont capables de courir 300 km en une journée. Le kenyan Kipsang (L0 = 1,82 m, M0 = 62 kg) court le marathon (42,2 km) en 2 h 03 min, sa vitesse moyenne est 5,7 m/s. Chez les femmes, l’américaine Griffith-Joyner (L0 = 1,70 m, M0 = 59 kg) court le 100 m en 10,49 s et l’américaine Radcliffe (L0 = 1,73 m, M0 = 54 kg) court le marathon en 2 h 15 min. Concernant les sports de forces, les hommes les plus forts sont capables de soulever une masse de 500 kg avec les bras au développé-couché ou au soulevé de terre. Aux Jeux Olympiques, l’iranien Rezazadeh (L0 = 1,86 m, M0 = 152 kg) est capable de soulever une barre de masse M∗ = 263 kg depuis le sol jusqu’au dessus de sa tête à l’épaulé-jeté. La russe Tatiana Kashirina (L0 = 1,77 m, M0 = 102 kg) soulève 186 kg à l’arraché. Le scarabée Ontophagus taurus mesure 10 mm et peut soulever 1141 fois son poids, la fourmi peut soulever 1400 fois son poids. Pour réaliser toutes ces performances, les athlètes poussent leur corps à son fonctionnement optimal pour établir un record et battre les adversaires, ou eux-mêmes (Sergeï Bubka a battu 35 fois son propre record du monde au saut à la perche). L’optimum n’est pas le même suivant le record à établir. Les sportifs les plus forts sont lourds, les plus endurants sont légers. Mais malgré la variabilité des morphologies et des caractères des sportifs qui établissent les records, le point commun à tous est cette optimisation. On s’attend ainsi à trouver des lois physiques régissant les records et qui dépendent d’un petit nombre de 9 10 paramètres dans toutes ces disciplines. Ce sont ces lois que nous discutons, pour la course et pour l’haltérophilie. La physique des sports à records commence avec les articles de J.B. Keller [8, 9], qui réussit à prédire l’évolution des records de course en utilisant des lois physiques simples (équation du mouvement et conservation d’énergie). (a) (b) D∗ Figure 4 – (a) Usain Bolt, détenteur des records du monde sur 100 m (9,58 s) et 200 m (19,19 s). (b) Vitesse moyenne D/T pour parcourir une course de distance D sur le temps T. Les points (●) représentent les records du monde enregistrés sur des courses de 45 m à 2 km et la courbe (−) présente la prédiction de Keller [9]. La figure 4 présente la vitesse moyenne D/T de course obtenue lors des records du monde sur des courses de 45 m à 2 km. Pour les courtes distances, la vitesse moyenne augmente avec la distance, alors qu’elle décroît pour les distances supérieures à D∗ . Keller utilise une méthode variationnelle pour déterminer la stratégie optimale permettant de parcourir une distance D en un temps T minimal. Ces deux paramètres sont liés par l’équation (1) : D = ∫ T 0 v(t) dt avec v(0) = 0 (1) Selon Keller la vitesse du coureur v(t) satisfait à l’équation cinétique (2) : dv dt = V − v τ (2) Cette équation signifie que l’athlète met un temps τ pour atteindre la vitesse V choisie. Cette vitesse V est majorée par la vitesse maximale de l’athlète Vmax. Keller écrit cette équation sous la forme d’une équation du mouvement par unité de masse : dv dt + v τ = f(t) avec f(t) ≤ F (3) où f(t) = V /τ est la force propulsive et −v/τ est la force résistive. La force f(t), choisie par le coureur, est bornée par sa force maximale F = Vmax/τ . Le coureur atteint sa vitesse maximale Vmax au bout d’un temps τ s’il déploie sa force maximale F. Il décrit ensuite la consommation d’énergie du coureur par unités de temps et de masse : dE dt = σ − fv avec E(T) ≥ 0 et E(0) = E0 (4) 11 avec σ le taux de production d’énergie par le métabolisme et fv le taux de dissipation d’énergie. E0 est l’énergie disponible à l’instant initial et l’énergie du coureur ne peut pas devenir négative. Les constantes τ , F, σ et E0 sont des caractéristiques physiologiques du coureur. La question est de déterminer la fonction f(t) permettant de maximiser D à T fixé, tout en satisfaisant les contraintes f(t) ≤ F et E(T) ≥ 0. Dans ce problème, Keller identifie deux régimes : — le régime des sprints (D ≤ D∗ ) pour lequel même si f(t) = F, l’athlète ne peut épuiser son énergie initiale E0 — le régime des courses de fond (D ≥ D∗ ) pour lequel l’athlète ne peut pas courir à vitesse maximale sous peine de ne pas pouvoir finir la course. Pour les courses courtes (D ≤ D∗ ), le coureur emploie sa force maximale F, sans dépenser toute l’énergie disponible. Keller calcule l’expression de la distance parcourue D pendant le temps T définie par la relation (1) et en déduit la vitesse moyenne D/T : D T = Vmax [1 + τ T (e −T/τ − 1)] (5) La relation (5) est tracée en ligne continue (−) sur la figure 4-(b) (en ajustant τ = 0,89 s et F = 12 N/kg) pour D ≤ D∗ . Ce régime où la vitesse est maximale est valable pour les courses de distance inférieures à D∗ , pour laquelle l’énergie est nulle à l’arrivée : E [T(D∗)] = 0. En intégrant l’équation (4) dans le cas f(t) = F, et en utilisant la condition d’énergie nulle à l’arrivée, Keller obtient la limite entre les deux régimes pour D∗ = 290 m. Pour les courses plus longues (D ≥ D∗ ), il faut prendre en compte la dissipation d’énergie. L’athlète choisit la force f(t) produite au cours du temps pour minimiser le temps de parcours et arriver à la fin de la course à énergie nulle. Keller utilise une méthode variationnelle et montre que la meilleure gestion de l’énergie consiste à courir à vitesse constante, après la phase initiale d’accélération. Dans ce régime des courses longues, on a donc v(t) = V et en intégrant la relation (4), on obtient : E(T) = E0 + σT − V 2T/τ = 0. On peut en déduire la valeur de V et la vitesse moyenne D/T : D T = (στ + E0τ T ) 1/2 (6) Cette relation (6) est tracée en ligne continue (−) sur la figure 4-(b) pour D ≥ D∗ , en ajustant σ = 42 J/kg.s et E0 = 2400 J/kg. Les prédictions de Keller permettent de retrouver l’allure des records enregistrés sur des courses de 50 m à 2 km, en ajustant les caractéristiques physiologiques des coureurs (τ - F - σ - E0). L’intérêt du modèle de Keller est qu’il permet de comprendre l’évolution des records de vitesse avec des lois physiques simples et fournit des données physiologiques sur la machine humaine. Un coureur de 80 kg a ainsi une réserve d’énergie de 190 kJ et son métabolisme produit 3,4 kJ/s. Sa réserve lui permet d’effectuer une marche de 250 m de dénivelé avant d’être fatigué. Et sa production d’énergie lui permet de retrouver la même énergie en 1 h. Sa force maximale de 960 N lui permet de soulever une masse de 98 kg, et il atteint sa vitesse maximale 13,5 m/s en 0,9 s. Cependant, ce modèle a quelques limites, en particulier sur la modélisation de la consommation d’énergie. En effet, Woodside [14] a montré qu’un taux de production d’énergie constant σ assure que l’athlète peut courir indéfiniment à vitesse constante V = στ ≈ 6,1 m/s, même après avoir épuisé toute son énergie. Cette vitesse 12 correspond à la moyenne du record sur 10 km. Pour des courses plus longues comme le marathon, la vitesse moyenne est inférieure : V = 5,7 m/s, on ne peut pas considérer une production d’énergie inépuisable. Woodside introduit un terme de fatigue (proportionnel à l’énergie dépensée), et réussit à étendre le résultat de Keller aux très longues courses (de 10 km à 275 km). Même si l’analyse de Keller reproduit bien les vitesses moyennes des records sur les courses de 50 m à 10 km, quelques faiblesses subsistent. Des mesures physiologiques ont montré que la vitesse des coureurs n’est pas constante, mais qu’elle varie d’environ 10% et le débit maximal d’oxygène consommé lors de l’effort ne reste pas constant comme postulé par Keller, mais augmente jusqu’à sa valeur maximale, et chute en fin de course. Plusieurs auteurs [86, 87, 88, 89, 90] ont tenté d’améliorer le modèle de Keller, mais avec la même démarche mathématique, ils ont obtenu les mêmes résultats. En s’appuyant sur une analogie hydraulique et des éléments physiologiques plus réalistes [91] Bonnans et Pons [92] ont réussi à rendre compte d’une stratégie optimale de course. Figure 5 – L’américain Justin Spring aux Jeux olympiques de Pékin le 9 août 2008. Photographie de Dylan Martinez Une dernière limite du modèle de Keller se trouve dans l’équation (4) : il n’y a pas de dissipation d’énergie à vitesse nulle. Si cette approximation peut être valable pour la course, où l’athlète est toujours en mouvement, elle est incompatible avec les épreuves de force telles que la croix de fer en gymnastique, réputée pour être épuisante, comme le laisse entrevoir Justin Spring sur le figure 5. Dans cette partie, nous nous intéressons à une autre grande catégorie de records : les records de force. Nous nous inspirons de la démarche de Keller pour comprendre quelle est la masse maximale qu’un homme peut soulever. Mais les équations cinétique (2) et mécanique (3) pourraient s’appliquer à n’importe quelle machine, et ne prennent pas en compte le fonctionnement du muscle. Les limites du modèle de Keller montrent qu’une approche purement macroscopique est insuffisante pour décrire correctement les records de force. Le muscle, générateur de la performance est disséqué dans le chapitre 1 pour comprendre l’origine moléculaire la contraction musculaire, et arriver à une loi qui rend compte des phénomènes microscopiques en jeu. Le chapitre 2 est consacré à l’étude de la dynamique d’un geste simple : le développé-couché. Nous verrons comment le couplage des descriptions mécanique macroscopique et musculaire microscopique nous permet d’expliquer la dynamique observée. Enfin, le chapitre 3 présente une analogie capillaire du muscle pour aller plus loin dans la compréhension microscopique de la contraction musculaire. Chapitre 1 Le muscle Figure 1.1 – Coupe longitudinale d’une fibre musculaire du psoas de lapin. Images de microscopie électronique, d’après H.E. Huxley [93]. Sommaire 1.1 Physiologie du muscle . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.1.1 Constitution du muscle . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.1.2 Contraction musculaire . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.2 Description phénoménologique du muscle . . . . . . . . . . . . . . 19 1.2.1 Impulsion nerveuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1.2.2 Relation force-longueur . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.2.3 Relation de Hill entre force et vitesse de contraction . . . . . . . . 21 1.3 Modélisations du muscle . . . . . . . . . . . . . . . . . . . . . . . . . 22 1.3.1 Modèles viscoélastiques actifs . . . . . . . . . . . . . . . . . . . . . . 23 1.3.2 Modèles microscopiques . . . . . . . . . . . . . . . . . . . . . . . . . 24 13 14 CHAPITRE 1. LE MUSCLE Introduction L’origine du mouvement a depuis toujours éveillé la curiosité des hommes et stimulé leur imagination. Selon leur caractère, ils ont pu les dessiner, les disséquer, les observer ou encore les soumettre à des expériences. C’est le recoupement de tous ces indices qui a permis de comprendre le fonctionnement du muscle. Nous revenons ici sur quelques théories des anciens et les éléments clés qui nous ont permis d’arriver à la compréhension actuelle du muscle. (a) (b) (c) Figure 1.2 – (a) Etude de bras, Léonard de Vinci, 1510 [94, 95, 96]. (b) Préparation du muscle de grenouille dans une seringue étanche, stimulé mécaniquement par Swammerdan en 1758 [97]. (c) Expérience de stimulation électrique d’une cuisse de grenouille un jour d’orage, réalisée par Galvani en 1791 [98]. A partir d’observations des mouvements des êtres vivants et de leur anatomie, diverses hypothèses ont pu être formulées. Louis de La Forge rapporte en 1664 [99] : « personne ne doute que les nerfs qui aboutissent dans les muscles ne servent au mouvement volontaire, mais tout le monde n’est pas d’accord de la manière qu’ils y servent. Les Médecins anciens semblent avoir cru que l’Ame s’en servait comme de la bride de nos chevaux, tirant tantôt un nerf, tantôt un autre, selon la partie qu’elle voulait mouvoir ». Aristote (IVe siècle avant J.C.) compare le mouvement animal à celui des automates : les os sont les fers et les bois des automates, les nerfs et les tendons (« neurona ») sont des ressorts qui se tendent et se détendent pour mouvoir le corps. L’origine du mouvement est l’Ame qui se trouve dans le coeur et transmet un souffle (« pneuma ») qui communique le mouvement. Ce pneuma influence Descartes qui l’interprète comme « un certain vent très subtil, ou plutôt une flamme très vive et très pure, qu’on nomme les Esprits Animaux », dans le traité de l’Homme en 1633 [100]. Ces esprits, dont le coeur est la source, entrent dans le cerveau, passent dans les nerfs et gonflent les muscles, qui se raccourcissent et transmettent le mouvement. Il compare le corps aux fontaines des jardins du Roi : « la seule force dont l’eau se meut en sortant de sa source est suffisante pour y mouvoir différentes machines. Et véritablement l’on peut fort bien comparer les nerfs de la machine que je vous décris, aux tuyaux des machines de ces fontaines ; les muscles et ses tendons aux autres divers engins et ressorts qui servent à les mouvoir ; les Esprits Animaux à l’eau qui les remue. [...] De plus la respiration et autres telles actions qui lui sont naturelles et ordinaires, et qui dépendant du cours des esprits, font comme le mouvement d’une horloge, ou d’un moulin que le cours ordinaire de l’eau peut rendre continu ». Tout le mouvement 1.1. PHYSIOLOGIE DU MUSCLE 15 du muscle se fait parce que son ventre s’emplit ou se vide de plusieurs petits Corps, que l’on nomme les Esprits Animaux. Au XVIIe siècle, plusieurs expériences prouvent que le muscle se contracte sans changer de volume. Swammerdan [97, 101] prélève un muscle de la cuisse d’une grenouille (noté b sur la figure 1.2-(b)) et le scelle dans une seringue en verre hermétique a , une goutte d’eau placée dans l’aiguille de la seringue e. Il stimule mécaniquement le nerf f pour provoquer la contraction du muscle. Il n’observe pas de déplacement de la goutte vers le haut, qui révélerait une augmentation de volume. Aucun fluide ne gonfle le muscle lors de la contraction. Glisson [102] étudie la contraction du bras d’un homme dans un caisson étanche rempli d’eau. Il n’observe aucune variation de la hauteur du liquide. Borelli [103, 104] pratique l’incision d’un muscle sous l’eau et n’observe aucune bulle d’air. L’hypothèse des nerfs étant des tuyaux creux est définitivement abandonnée après l’invention du microscope. Puis vient la théorie de l’électricité animale sécrétée par le cerveau et qui se décharge lorsque le nerf et le muscle sont reliés par un conducteur. De vives contractions des muscles sont observées en stimulant électriquement les nerfs. Galvani [98] découvre en 1791 que la contraction a lieu même lorsque la stimulation électrique est éloignée et que le nerf est relié à un long conducteur (qui sert d’antenne). Un jour d’orage, il place une cuisse de grenouille reliée à un long fil conducteur sur la terrasse et observe encore des contractions grâce au « fluide électrique ». Puis les découvertes sur le muscle se s’enchaînent, mêlant les observations de plus en plus précises de microscopie électronique et de diffraction de rayons X [105] et les expériences comportementales. La compréhension actuelle de la contraction musculaire est venue du croisement entre méthodes complémentaires : l’observation du mouvement, les expériences sur le muscle et l’observation des constituants du muscle par la dissection et l’imagerie. Nous présentons les constituants du muscle et le mécanisme de la contraction dans la partie 1.1. La partie 1.2 revient sur les expériences comportementales historiques qui ont permis de caractériser le muscle de manière macroscopique avant d’avoir une idée des mécanismes microscopiques. La partie 1.3 présente les différents modèles de la contraction musculaires qui ont été formulés pour rendre compte des observations expérimentales. 1.1 Physiologie du muscle 1.1.1 Constitution du muscle Le corps humain compte 639 muscles qui représentent 40 % de la masse sèche du corps, plus que n’importe quel organe [106]. Leur fonction principale consiste à produire une force ou un mouvement en se contractant. Notre étude porte sur le muscle strié squelettique, qui est un tissu musculaire à contraction volontaire, constitué de fibres à plusieurs noyaux, striées longitudinalement et transversalement. Les muscles squelettiques sont reliés aux os par les tendons et ont pour fonction principale la locomotion. La figure 1.3 montre de quoi sont faits les muscles à différentes échelles. Un muscle est formé de faisceaux de fibres musculaires parallèles (L ∼ 10 cm, φ ∼ 100µm). Chaque fibre contient elle-même des faisceaux de myofibrilles parallèles (L ∼ 10 cm, φ ∼ 1µm) entourée de réticulum sarcoplasmique. Chaque myofibrille peut être décomposée dans sa longueur en unités fonctionnelles élémentaires : les sarcomères (L ∼ 3µm, φ ∼ 0,5µm), associés en série. Le sarcomère est ainsi la cellule contractile élémentaire, et le muscle se construit en associant les sarcomères en série, et les myofibrilles en parallèle. C’est cette structure qui 16 CHAPITRE 1. LE MUSCLE (a) (b1) (b2) (b3) 0, 5 µm 50 µm 0, 2 µm myosine actine ponts (b4) 0, 1 µm Figure 1.3 – Schéma des différents constituants du muscle (a). Images de microscopie électronique, tirées de H.E. Huxley [93] : coupe longitudinale d’une myofibrille (b1), zoom sur quelques sarcomères (b2), à l’intérieur du sarcomère sur les filaments de myosine et d’actine (b3) et sur les ponts actine-myosine (b4). (a) (b) Figure 1.4 – Coupes longitudinale (a) et transversale (b) d’une fibre d’un psoas de lapin. Images de microscopie électronique, d’après H.E. Huxley [93]. Le segment noir mesure 0,5 µm. 1.1. PHYSIOLOGIE DU MUSCLE 17 est responsable de l’aspect strié des fibres musculaires squelettiques, visible sur les photos des figures 1.3 et 1.4. Les muscles striés squelettiques de tous les êtres vivants (mammifères, poissons, oiseaux, insectes...) sont construits à partir de la même brique élémentaire : le sarcomère, dont les caractéristiques varient très peu d’une espèce à l’autre [107]. La section du biceps humain étant de l’ordre de 15 cm2 , il contient environ 5.104 fibres musculaires soit 5.108 myofibrilles et chacune est décomposée en 105 sarcomères dans la longueur. Chaque sarcomère est constitué d’un réseau alterné de filaments épais de myosine et de filaments fins d’actine, tous parallèles. Lors de la contraction musculaire, les filaments de myosine tirent sur les filaments d’actine. Ces derniers coulissent entre les filaments de myosine, si bien que leur longueur reste inchangée mais le sarcomère se contracte, comme illustré sur la figure 1.5. La contraction simultanée de tous les sarcomères des fibres sollicitées provoque la contraction du muscle. myosine actine (a) (b) (c) (d) (e) Figure 1.5 – (a) Coupes longitudinales d’un sarcomère relâché (en haut) et contracté (en bas) d’un psoas de lapin en microscopie électronique. (b) Schéma du coulissement des filaments d’actine autour du filament de myosine. (c, d, e) Coupes transversales du sarcomère : réseaux des filaments d’actine (c), des filaments de myosine (e) et zone de recouvrement entre les filaments d’actine et de myosine (d). Les images de microscopie électronique sont empruntées à H.E. Huxley [93]. 1.1.2 Contraction musculaire Le sarcomère est donc la brique élémentaire du muscle squelettique et pour comprendre la contraction musculaire il faut s’intéresser à l’interaction entre les myofilaments de myosine et d’actine qui le constituent. Le filament épais est un polymère constitué de quelques centaines de protéines de myosine, associées à d’autres protéines qui assurent la cohésion 18 CHAPITRE 1. LE MUSCLE 38, 5 nm 14 nm 43 nm 5 nm 140 nm (a) (b) (c) (d) (e) (f1) (f2) (f3) (f4) (f5) Figure 1.6 – Interaction entre les filaments de myosine et d’actine : (a) Filament épais, constitué de protéines de myosine. (b) Protéine de myosine, composée d’une tige longue de 140 nm et d’une double tête, (c) Filament fin, constitué de protéines d’actine, de troponine et de tropomyosine. Mécanisme d’interaction des têtes de myosine du filament épais avec le filament fin : états relâché (d) et contracté (e). Mécanisme d’action d’une tête de myosine (f1 à f5). de l’ensemble. Chaque protéine de myosine est constituée d’une partie linéaire de 140 nm de long, flexible en au moins deux points, et d’une double tête longue de 10 nm, sur laquelle se trouve le site d’interaction avec l’actine. Les protéines de myosine sont torsadées pour former le myofilament épais et les têtes de myosine sont réparties de manière hélicoïdale avec un pas de 43 nm. Le myofilament d’actine est formé de protéines d’actine, de tropomyosine et de troponine. Les sites actifs du filament fin sont distants de 38,5 nm. Dans le muscle au repos (cf. figure 1.6-(d)), les complexes protéiques tropomyosinetroponine écrantent les sites actifs du filament fin et bloquent l’action des têtes de myosine, qui sont libres (f1) [108, 109, 110]. Lorsqu’on décide de contracter le muscle, un potentiel d’action parcourt un motoneurone, et se propage le long des fibres musculaires associées. Des ions calcium sont relâchés par le réticulum sarcoplasmique, se fixent sur la troponine, modifient la conformation de la tropomyosine et démasquent les sites de liaison des têtes de myosine (e). Dans tous les sarcomères de la fibre, les têtes de myosine se lient à l’actine (f2), puis basculent de 60○ et tirent le filament d’actine (f3), grâce à l’énergie apportée par une molécule d’ADP et un phosphate. Pour se détacher de l’actine (f4), chaque tête de myosine doit capter une molécule d’ATP. L’ATP 1 est ensuite hydrolysé en ADP et phosphate, et la tête se déplie (f5). Le mécanisme se répète aussi longtemps que les ions calcium sont présents, donc tant que le potentiel d’action est maintenu et que l’organisme fournit de l’énergie, sous forme d’ATP. Le travail conjoint de nombreuses têtes sur chaque filament de myosine permet de faire coulisser les filaments d’actine entre les filaments de myosine dans chaque sarcomère. Quand le potentiel d’action cesse, les ions calcium sont repompés dans le réticulum sarcoplasmique, les têtes absorbent une dernière molécule d’ATP pour se libérer et le muscle se relâche. Le carburant du muscle est l’ATP, qui permet de décrocher les têtes de myosine et d’amorcer un nouveau cycle. (Lorsqu’on meurt, le réticulum sarcoplasmique devient perméable aux ions calcium, les têtes de myosine s’accrochent aux filaments d’actine, et comme on n’a plus d’ATP pour les détacher, le muscle reste contracté. Ce phénomène est appelé la rigidité cadavérique.) 1. L’adénosine tri-phosphate (ATP) est la molécule qui fournit (par hydrolyse) l’énergie nécessaire aux réactions chimiques du métabolisme, chez tous les êtres vivants. 1.2. DESCRIPTION PHÉNOMÉNOLOGIQUE DU MUSCLE 19 Le rôle des ponts actine-myosine est le point clé de la théorie des filaments coulissants [111] développée par Huxley (cf. paragraphe 1.3.2). Plusieurs expériences de microscopie optique ont montré que [112] que la force produite par une fibre musculaire dépend du recouvrement des filaments d’actine et de myosine et donc du nombre de ponts actinemyosine (cf. paragraphe 1.2). La force développée par une tête de myosine au cours d’un cycle a pu être déterminée expérimentalement assez récemment f ≃ 3 pN [113, 114, 115, 116] ainsi que la durée typique d’un cycle τcycle ≈ 10 ms. La contraction simultanée des sarcomères entraîne le raccourcissement des myofibrilles et la contraction de la fibre musculaire. Quand plusieurs fibres musculaires se contractent ensemble, on observe un mouvement macroscopique. 1.2 Description phénoménologique du muscle Avant que les mécanismes moléculaires de la contraction musculaire soient expliqués, plusieurs expériences macroscopiques ont permis de caractériser le muscle. Nous décrivons dans cette partie comment la force développée dépend de l’impulsion nerveuse reçue, de la longueur du sarcomère ou de sa vitesse de contraction. 1.2.1 Impulsion nerveuse Depuis les premières découvertes de Galvani, on a compris que le muscle se contracte lorsqu’il est stimulé électriquement. La réponse mécanique d’une fibre musculaire dépend de la fréquence des stimulations qui lui sont imposées. F (%) F (%) F (%) t(ms) (a) (b) (c) Figure 1.7 – Evolution temporelle de la force générée par le muscle en réponse à une stimulation S1 isolée, ou si les stimulations S2 et S3 sont suffisamment espacées (a). Sommation des réponses si S2 et S3 sont plus rapprochées (b) et (c). Lorsque la fibre musculaire est stimulée par une impulsion électrique, elle répond par 20 CHAPITRE 1. LE MUSCLE un phénomène électrique et un phénomène mécanique. Le phénomène électrique, qui correspond au potentiel d’action musculaire, dure de 1 à 3 ms. La réponse mécanique est une secousse (d’une durée de 10 à plusieurs centaines de ms), qui arrive après une phase de latence plus ou moins longue. Au niveau de la fibre, la réponse suit une loi de tout-ou-rien : si l’intensité du choc est suffisante pour dépolariser la membrane de la fibre (et laisser passer les ions calcium), on observe une secousse d’intensité maximale, sinon rien. L’amplitude de la réponse et le temps de latence peuvent varier en fonction du type de fibre musculaire (lente ou rapide). Au niveau du muscle, la réponse apparaît à partir d’un seuil puis croît graduellement lorsque l’intensité augmente, à mesure que le nombre de fibres sollicitées augmente. F (%) t(ms) A B C Figure 1.8 – Evolution temporelle de la force générée par le muscle en réponse à un train de stimulations S. Si la fréquence des stimulations est faible, on observe une secousse isolée à chaque stimulus : A. Si la fréquence augmente, on observe une force d’amplitude constante, modulée par la fréquence de stimulation. L’amplitude de la force augmente avec la fréquence de stimulation : B et C. En plus de la sommation spatiale des réponses mécaniques de chaque fibre, il existe une sommation temporelle. Ainsi, deux stimuli séparés d’un intervalle suffisant (supérieur à la durée de la secousse) produisent deux secousses identiques (cf. figure 1.7-(a)). Mais si le stimulus de la deuxiè