Date of Award

Spring 2011

Document Type


Degree Name

Master of Science in Education (MSEd)


Human Movement Sciences


Athletic Training

Committee Director

Bonnie Van Lunen

Committee Member

Nelsen Cortes

Committee Member

Stacie Ringleb

Call Number for Print

Special Collections LD4331.E44 B36 2011


Over the past decade, youth lacrosse participation has substantially increased across the United States. As well, fatigue has been shown to have a detrimental effect on lower extremity biomechanics, potentially increasing the risk for injury. Yet, the effects of fatigue on lower extremity biomechanics in the young adolescent athletic population have not been addressed. The purpose of this study was to assess the effects of a fatigue protocol [Slow Linear Oxidative Fatigue Protocol (SLO-FP)] on lower extremity biomechanics during a side-step cutting task (SCT) in adolescent male lacrosse athletes. This quasi-experimental design was conducted in a controlled laboratory with 24 male recreational lacrosse players (age=11.6±1.5 years; height=153.9±14.0 cm; mass=44.7±2.2 kg). Each subject performed five successful trials of an unanticipated SCT before and after the SLO-FP. A VO2peak test was performed prior to the SLO-FP. The SLO-FP consisted of four intervals; each interval included four-minutes of jogging (speed set at 70% max VO2peak) and one minute of running (speed set at 90% max VO2peak) for a total of 20 minutes. Dependent variables included knee flexion (KF) angles, hip flexion (HF) angles, knee abduction moments (KABM), hip abduction angles (HAB), hip abduction moments (HABM) and vertical ground reaction force (VGRF) at initial contact. Repeated measures ANOVAs were conducted to compare statistical differences between pre and post SLO-FP. Alpha level was set a priori at 0.05. Fatigue significantly altered some dependent measures which were: decreased VGRF (0.256±0.123 N/mBW to 0.185±0.15 N/mBW, p = 0.037), KF (-24.51±7.9° to -20.96±5.39°, p = 0.018), adductor moment for KABM (0.851±0.135 Nm/Kgm to 0.016±0.096 Nm/Kgm, p =0.016), HF (56.31±17.48° to 51.88±16.25°, p =0.003), HAB (-14.85±5.08° to -12.33±5.98°, p=0.002); and a shift from an adductor moment to an abductor moment for HABM (0.034±0.22 Nm/Kgm to -1.52±0.21 Nm/Kgm, p =0.019). Post-fatigue, the adolescent athletes adopted a cutting position that has been shown to potentially increase the demands at the knee. These results suggest that fatigue affects lower extremity biomechanics and may put these individuals at increased risk of injury. It is important that injury prevention programs start at early ages, and take into account the effects of fatigue.


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