Electromyographic Analysis of the Vastus Medialis Oblique and Vastus Lateralis Muscles in Patellofemoral Pain Syndrome Rehabilitation Exercices

Abstract

Patellofemoral pain syndrome is a pathology commonly found in Physical Therapy practice. This pathology is generally caused by biomechanical changes that lead to a lateral glide of the patella. It has been advocated that strenthening of the vastus medialis oblique (VMO) muscle is essential for the treatment of the patellofemoral pain syndrome. However there is a lack of consensus of the VMO muscle can be accomplished. The objective of this study was to verify through surface electromyography the activation pattern of hte VMO and vastus lateralis (VL) muscles in four exercices usually prescribed for strenthening of these muscles. Nine normal individuals without significant lower limb malalignment participated in the study. ANOVA for repeated measures revealed a significant decrease (p<0,05) in the integrated electromyography values of the VL muscle during open kinetic, isometric knee extension exercise with hip external rotation and knee at 30º of flexion. It was also observed an increase in the VMO/VL ratio during the same exercise, caused by a decrease in the activation of the VL. It was  not observed any statistical difference in the activation any statistical difference in the activation values of the medialis muscle during open kinetic, isometric knee extension exercise with foot inversion and knee at 30º of flexion, open kinetic, isometric knee extension exercise with hip in neutral and knee at 30º of flexion and closed kinetic, isometric knee extension with hip in external rotation and knee at 30º of flexion. More studies are suggested to test if the findings of the current study will similar in subjects with patellofemoral pain syndrome.