COMPARISON OF 5 ISOMETRIC EXERCISES IN THE RECRUITMENT OF THE VASTUS MEDIALIS OBLIQUE IN PERSONS WITH AND WITHOUT PATELLOFEMORAL PAIN SYNDROME

Strengthening of the vastus medialis oblique (VMO) has been advocated as a treatment for patellofemoral pain syndrome (PFPS), as weakness of this component of the quadriceps is postulated to contribute to malal ignment of the patella. This study investigated the surface electromyo graphic activity (EMG) of the VMO relative to the vastus lateralis (VL ) during five isometric exercises in eight PFPS female subjects and 19 controls. The area under the EMG curve of each muscle was normalized to the EMG area acquired while subjects performed a submaximal isometr ic contraction (50% of maximum voluntary contraction), and the ''norma lized'' outcome measure was expressed as a proportion (VMO:VI). A two- factor repealed measures analysis of variance indicated no differences in the VMO:VL proportion between the control group and PFPS participa nts across the five exercises (p > .05). The VMO:VI proportions for me dial tibial rotation and knee extension combined and knee extension al one were significantly greater than for the other three exercises (p < 0.005). Hip adduction or the combination of hip adduction and knee ex tension did not result in greater recruitment of the VMO compared with the VI.