Relationship Between Hip and Knee Muscle Volume and Neuromuscular Function in Women With Patellofemoral Pain.

OBJECTIVE

To investigate the relationship between hip and knee muscle volume and neuromuscular function (isokinetic strength, rate of torque development, and torque variability) in women with patellofemoral pain (PFP).

DESIGN

Cross-sectional study.

SETTING

University research laboratory.

PARTICIPANTS

Twenty women with PFP.

MAIN OUTCOME MEASURES: Isokinetic strength (60 degrees/second and 180 degrees/second), rate of torque development, and torque variability were assessed with an isokinetic dynamometer for hip extension, hip abduction, knee extension, and knee flexion. Muscle volume of the lower extremity muscles (cm 3 /kg·m) was quantified through magnetic resonance imaging. Pearson r correlation or Spearman ρ coefficients were calculated to evaluate the relationship between muscle volume and neuromuscular function, with significance set at P < 0.05.

RESULTS

Muscle volume for all muscle groups was moderately correlated with isokinetic strength at 60 degrees/second, r ≥ 0.452, P ≤ 0.046. Hip abduction and extension were moderately correlated with isokinetic strength at 180 degrees/second, r ≥ 0.485, P ≤ 0.030; however, no significant correlations were identified between muscle volume and rate of force development or torque variability, P < 0.05.

CONCLUSIONS

The results suggest that isokinetic strength is associated with hip and knee muscle volume in women with PFP; however, additional measures of neuromuscular function (rate of torque development and torque variability) are not associated with muscle volume in lower extremity muscles.