LE3 .A278 2021

2021

Lattimer, Lauren

Acadia University

Bachelor of Kinesiology

Honours

Kinesiology

Kinesiology

INTRODUCTION: Neuromuscular control provides joint stability, and it has the potential to influence the risk of sustaining athletic injuries via delayed muscle activation, decreased force production, and altered activation patterns. Neuromuscular fatigue will increase the effects of inadequate neuromuscular control, further increasing the risk of injury. The hip abductors and external rotators function to stabilize the hip joint during dynamic activity, preventing movement into adduction and internal rotation. Movement into these positions are associated with lower extremity injuries, such as anterior cruciate ligament (ACL) injuries.Typically, majority of ACL injuries are due to non-contact mechanisms and occur during weight acceptance phase of rapid athletic maneuvers such as changing directions, landing from a jump, or pivoting. Therefore, the purpose of this research was to investigate the effect of a hip muscle fatigue protocol on hip joint kinematics in females during dynamic jump landings and unanticipated cutting tasks. METHODS: Twenty-two female participants were initially recruited for this study, of those twenty-two participants, sixteen (mean age 20.38±0.96 years) of them had complete kinematic data sets that went on to be analyzed. They completed a series of triple hop (THop) tasks and 90o and 135o unanticipated cutting tasks pre- and post-fatigue protocol. The hip kinematics were measured using a 3D motion capture system for participants dominant leg only during the stance phase of tasks and were then compared pre-and post-fatigue. The fatigue protocol specifically targeted the external rotators and abductors at the hip, consisting of three sets of modified stork stance and resisted lateral step exercises. A one-way repeated measures MANOVA was used to determine effects of time on hip kinematics. RESULTS: Statistical analysis revealed a significant effect of fatigue on hip flexion angle (p=0.037) during the THop testing. There was a significant effect of fatigue on hip abduction angle (p=0.006) during the 90o unanticipated cutting task. An analysis of clinical data revealed a significant effect of fatigue on performance of THop, decreasing the distance travelled. DISCUSSION: The results indicate that when participants hip abductors and external rotators are in a fatigued state , they will demonstrate hip joint kinematics associated with lower extremity injury during dynamic tasks. These positions include decreased hip flexion during the THop and decreased hip abduction during 90o unanticipated cut post-fatigue. The position of no return described for ACL injuries includes both of these positions, indicating that hip musculature fatigue possibly increased the risk of ACL injuries in participants.This suggests that as the hip musculature fatigues the joint becomes unstable, impacting the generation of hip flexion and resistance of hip adduction collapse during dynamic tasks, meaning participants will be at a greater risk for sustaining injuries. IMPORTANCE: The findings of this study emphasize the importance of targeting hip musculature strength and endurance when designing injury prevention and intervention programs. Additionally, it showed that incorporating fatigue into training programs may be beneficial for identifying athletes that execute dynamic maneuvers with high-risk positions. This information could be used to create unique training programs for athletes to correct poor neuromuscular control and mechanics.

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https://scholar.acadiau.ca/islandora/object/theses:3617