Activity of the Quadriceps during Semisquat and Squat Exercises with Isometric Hip Adduction and Abduction in Young Healthy Persons

ABSTRACT

OBJECTIVE: To determine the effects of isometric hip adduction and abduction on the activity of vastus medialis obliquus (VMO) and vastus lateralis (VL) during semisquat and squat exercise. METHOD: Thirty healthy male subjects without history of knee pain were recruited. Subjects performed a traditional exercise combined with hip adduction and abduction during semisquat and squat exercise. A total of 3 repetitions lasting 6 seconds each were executed following two-minute intervals. The EMG signals were collected from VMO and VL of the dominant leg. The data were normalized to the maximal isometric voluntary contraction of VMO and VL at 90degrees of knee flexion using isokinetic dynamometer and analysed in terms of their RMS values. RESULTS: The activity of both VMO and VL was significantly greater during both semisquat and squat exercise with hip adduction and abduction than without hip adduction and abduction. The VMO/VL ratio was significantly greater. The squat exercise produced significantly greater VMO and VL activity than the semisquat exercise, regardless of hip position. However, there were no significant differences in VMO/VL ratio between semisquat and squat exercise. CONCLUSION: Combining isometric hip adduction using theraband during semisquat exercise produced higher VMO/ VL ratio through more selective VMO activation and could be easy and effective rehabilitation program in patellofemoral pain syndrome.