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This study attempted to determine the effect of eccentric quadriceps femoris, hamstring, and placebo fatigue on stance limb dynamics during the plant-and-cut phase of a crossover cut. Twenty female college students (task trained) were tested. Hamstring fatigue resulted in decreased peak impact knee flexion moments (p = .01), increased internal tibial rotation at peak knee flexion (p = .05), and decreased peak ankle dorsiflexion (p = .05). Quadriceps fatigue resulted in increased peak ankle dorsiflexion moments (p < .01), decreased peak posterior braking forces (p = .01), decreased peak knee extension moments (p = .01), delayed peak knee flexion (p = .01), delayed peak propulsive forces (p < .01), and delayed subtalar peak inversion moments (p = .05). Fatigue of either muscle group produced earlier peak ankle plantar flexion moments (p = .05) and decreased peak propulsive knee flexion moments (p = .05). Variables requiring further study (p = .1) provide discussion data. Soleus, gastrocnemius, tibialis anterior, and deep posterior compartment calf muscles serve as dynamic impact force attenuators, compensating for fatigued proximal muscles.
J Orthop Sports Phys Ther. 1997;25(3):171-184.
Key Words: women, muscle, fatigue, compensatory dynamics