Hip abductor weakness and lower extremity kinematics during running.

OBJECTIVE To determine if females with hip abductor weakness are more likely to demonstrate greater knee abduction during the stance phase of running than a strong hip abductor group. STUDY DESIGN Observational prospective study design. SETTING University biomechanics laboratory. PARTICIPANTS 15 females with weak hip abductors and 15 females with strong hip abductors. MAIN OUTCOME MEASURES Group differences in lower extremity kinematics were analyzed using repeated measures ANOVA with one between factor of group and one within factor of position with a significance value of P < .05. RESULTS The subjects with weak hip abductors demonstrated greater knee abduction during the stance phase of treadmill running than the strong group (P < .05). No other significant differences were found in the sagittal or frontal plane measurements of the hip, knee, or pelvis. CONCLUSIONS Hip abductor weakness may influence knee abduction during the stance phase of running.