LE3 .A278 2021

2021

Lattimer, Lauren

Acadia University

Bachelor of Kinesiology

Honours

Kinesiology

Kinesiology

INTRODUCTION: The combined manifestation of neuromuscular fatigue and reactive agility tasks create high-risk situations for ACL injury and these components are rarely discovered independent of one another. Decreased force production, delayed neuromuscular activation and hindered motor coordination that results from neuromuscular fatigue leads to hazardous compensatory movement strategies that can often place excessive strain on the ligaments of the knee joint. Proximal hip musculature plays an integral role in the dynamic stabilisation and force attenuation of the lower extremity and thus has been postulated to have influence over the positioning of more distal joints, including the knee. Considering the high demand of unanticipated cutting and jumping tasks on the musculoskeletal system, developing an understanding of the impact of intrinsic hip muscles over knee kinematics and kinetics during demanding tasks is of great importance to minimizing injury risk. METHODS: Twenty-two female subjects were recruited to participate in the study with sixteen subjects (mean age; 20.38±0.96) data being collected and analyzed. Subjects completed pre-and post-testing following a fatigue protocol that targeted the external rotators and abductors of the hip. The pre-and post-testing consisted of triple hop (for distance) and a series of unanticipated cutting tasks. All fatigue and dynamic testing were conducted solely on the subjects’ dominant leg. Force plate data and 3D motion capture was used to examine knee kinematics and kinetics during testing. A two-way repeated measures MANOVA was employed to determine the effects of fatigue on variables of performance of the dynamic tasks. RESULTS: Statistical analysis showed a significant decrease in muscle strength and triple hop performance (p=0.026) following fatigue. More specifically, a significant decrease in knee flexion angles (p=0.007) was observed in the POST condition of triple hop testing. IMPORTANCE: The neuromuscular fatigue of proximal musculature (intrinsic hip muscles) is capable of affecting movement patterns at more distal joints, being the knee. The compensations that occurred as a result of hip muscle fatigue placed the knee in positions of higher ACL injury risk during dynamic tasks. Due to this, integration of proximal muscle strengthening into rehabilitation and prevention programs for lower extremity injuries should be considered. Furthermore, incorporating a fatiguing element into return to play testing may be beneficial in solidifying return to play decisions following injury.

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https://scholar.acadiau.ca/islandora/object/theses:3615