The Effects of Exhaustive Exercise on ACL Injury Risk by Christopher Asplund A THESIS submitted to Oregon State University University Honors College in partial fulfillment of the requirements for the degree of Honors Baccalaureate of Science in Exercise and Sport Science (Honors Associate) Presented May 31, 2016 Commencement June 2016 AN ABSTRACT OF THE THESIS OF Christopher Asplund for the degree of Honors Baccalaureate of Science in Exercise and Sport Science presented on May 31, 2016. Title: The Effects of Exhaustive Exercise on ACL Injury Risk. Abstract approved: ______________________________________________________ Samuel T. Johnson Background: Certain knee movements place the anterior cruciate ligament (ACL) at risk of injury. These injuries commonly affect athletes especially at the end of events. The purpose of this study was to determine the effects of exhaustive exercise on frontal plane hip and knee mechanics during two tasks in order to better understand the risk factors for ACL injury. Methods: Forty, healthy, active female subjects performed drop jump landings (DJ) and side-step cut landings (SSC) before and after a 30-minute bout of exercise. The following frontal plane dependent variables were collected during the tasks: maximum hip and knee moments, angle at initial contact, maximum angle prior to maximum knee flexion, and overall displacement. For each dependent variable a 2 (task) x 2 (time) repeated measures ANOVA was performed. Results: There were no significant interactions or main effects for time, but there was a significant main effect for task for hip angle at initial contact (p=0.006), hip angle displacement (p=0.032), and hip abduction moment (p<0.001). Conclusion: The subjects did not have changes in frontal plane mechanics in response to the exercise. The SSC had greater hip abduction at initial contact, abduction moments, and overall adduction than the DJ. Key Words: ACL, fatigue, biomechanics, knee abduction Corresponding e-mail address: [email protected] ©Copyright by Christopher Asplund May 31, 2016 All Rights Reserved The Effects of Exhaustive Exercise on ACL Injury Risk by Christopher Asplund A THESIS submitted to Oregon State University University Honors College in partial fulfillment of the requirements for the degree of Honors Baccalaureate of Science in Exercise and Sport Science (Honors Associate) Presented May 31, 2016 Commencement June 2016 Honors Baccalaureate of Science in Exercise and Sport Science project of Christopher Asplund presented on May 31, 2016. APPROVED: Samuel T. Johnson, Mentor, representing School of Biological and Population Health Sciences Marc F. Norcross, Committee Member, representing School of Biological and Population Health Sciences Eunwook Chang, Committee Member, representing School of Biological and Population Health Sciences Toni Doolen, Dean, University Honors College I understand that my project will become part of the permanent collection of Oregon State University, University Honors College. My signature below authorizes release of my project to any reader upon request. Christopher Asplund, Author ACKNOWLEDGEMENTS First, I would like to offer my sincerest gratitude to my mentor, Dr. Sam Johnson. He has taught me so much about research methods, laboratory work, and the writing process. He was always there to offer me support and encouragement when I needed it, while also pushing me to achieve my full potential. I truly could not have done this without him. I would also like to extend my thanks to my committee members. To Dr. Marc Norcross and Eunwook Chang, I have learned so much from both of you in the laboratory and the classroom. Thank you for your understanding, patience, and dedication to helping me learn. Thank you to the other students in the laboratory with whom I learned alongside. To Baker Cronin and Anne Pollard, you were my role models as we progressed through data collection and always inspired me to hold my work to the highest standards. Lastly, I would like to thank my parents. Thank you for always motivating and supporting me in everything that I do. I would not be where I am today with you. TABLE OF CONTENTS Page Chapter 1: Introduction………………………………………………………………..1 Chapter 2: Literature Review………………………………………………………….6 Chapter 3: Methods………………………………………………………………..…26 Chapter 4: Results……………………………………..……………………………..34 Chapter 5: Discussion……………………..…………………………………………40 Chapter 6: Conclusion………………......……………………………………………46 References……………………………………...…………………………………….47 Appendix: ANOVA Tables…………………………………………………………..57 LIST OF FIGURES Page Figure 1: Drop jump landing task ……………………………………………….…..33 Figure 2: Side-step cut landing task ……………………………………………...….33 Figure 3: Hip adduction angle at initial contact…………………………………...…36 Figure 4: Maximum hip adduction angle…………………………………………….36 Figure 5: Hip angle displacement……………………………………………………37 Figure 6: Internal hip abduction moment (normalized by height and body weight)...37 Figure 7: Knee adduction angle at initial contact……………………………………38 Figure 8: Maximum knee adduction angle……………….…………….……………38 Figure 9: Knee angle displacement…..………………………………………………39 Figure 10: Internal knee adduction moment (normalized by height and body weight)……………………………………………………………………………….39