Effect of lower-extremity muscle fatigue on postural control

Gribble PA, Hertel J. Effect of lower- extremity muscle fatigue on postural control. Arch Phys Med Rehabil 2004;85:589-92. Objective To examine the effects of fatigue of the lower extremity on postural control during single-leg stance. Design Pretest-posttest. Setting University research laboratory. Participants Fourteen healthy volunteers (age, 21±2y) with no history of lower-extremity injury or neurologic deficits. Interventions Testing consisted of isokinetically fatiguing the sagittal plane movers of the ankle, knee, or hip with measures of static postural control. Postural control was assessed with three 30-second trials during unilateral stance with eyes open. Main outcome measure Center of pressure excursion velocity (COPV) in the frontal and sagittal planes. Results Fatigue at the knee and hip led to postural control impairment in the frontal plane, whereas fatigue at the ankle did not. In the sagittal plane, fatigue at all 3 joints contributed to postural control impairment. Conclusions Our results suggest that there is an effect of localized fatigue of the sagittal plane movers of the lower extremity on COPV. It appears that fatigue about the hip and knee had a greater adverse affect on COPV.