THE DIFFERENCE OF ELECTROMYOGRAPHIC ACTIVITIES OF VASTUS MUSCLE IN OPEN AND CLOSED KINETIC CHAIN EXERCISES BETWEEN SUBJECTS WITH AND WITHOUT PATELLOFEMORAL PAIN SYNDROME

Abstract

In this study, ten normal subjects and ten patients with patellofemoral pain syndrome (PFPS) were enrolled for knee isokinetic exercise test and closed kinetic chain exercise by squatting-standing respectively. Surface electromyography was applied to vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during exercise. According to the integrated electromyography, VMO/VL ratio was calculated by dividing normalized EMG of VMO by those of VL. The statistic results revealed that the VMO/VL ratio of patients with PFPS was significantly lower than those of normal subjects during knee isokinetic exercise (p=0.047). However, there is no statistic difference in VMO/VL ratio between the subjects with and without PFPS during closed kinetic chain exercise (p=0.623)