title: The effect of quadriceps femoris, hamstring, and placebo eccentric fatigue on knee and ankle dynamics during crossover cutting.
abstract: 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 < or = .01), increased internal tibial rotation at peak knee flexion (p < or = .05), and decreased peak ankle dorisflexion (p < or = .05). Quadriceps fatigue resulted in increased peak ankle dorsiflexion moments (p < .01), decreased peak posterior braking forces (p < or .01), decreased peak knee extension moments (p < or = .01), delayed peak knee flexion (p < or = .01), delayed peak propulsive forces (p < .01), and delayed subtalar peak inversion moments (p < or = .05). Fatigue of either muscle group produced earlier peak ankle plantar flexion moments (p < = .05) and decreased peak propulsive knee flexion moments (p < or = .05). Variables requiring further study (p < or = .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.
authors.affiliation: University of Kentucky, Sports Medicine Center, Lexington 40536, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Nyland
authors.forename: R
authors.initials: R
authors.lastname: Shapiro
authors.forename: D N
authors.initials: DN
authors.lastname: Caborn
authors.forename: A J
authors.initials: AJ
authors.lastname: Nitz
authors.forename: T R
authors.initials: TR
authors.lastname: Malone
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000843:Ankle Joint / Q000502:physiology*; D005260:Female; D006801:Humans; D007700:Kinetics; D007718:Knee Injuries / Q000209:etiology / Q000517:prevention & control; D007719:Knee Joint / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D012016:Reference Values; D012420:Running / Q000502:physiology*; D014741:Video Recording