Abstract
Anterior knee pain syndromes are among the most common sources of pain and dysfunction at the knee. Numerous attempts have been made to identify exercises that selectively promote action of the vastus medialis oblique (VMO) muscle in order to counter lateral patellar tracking. The purpose of this study was to evaluate (via EMG) action of the VMO muscle versus the vastus lateralis (VL) muscle during two exercises. First, EMG ratios were evaluated during isolated knee extension and then repeated with isometric hip adduction during knee extension. The results of this study demonstrated a statistically-significant decrease in VL activity during knee extension combined with isometric hip adduction. Inhibition of the vastus lateralis allows more favorable medialization of the patella by the VMO, potentially making knee extension with isometric hip adduction an effective adjunct to patellofemoral rehabilitation.