Yukihisa YAGATA

Department of Orthopaedic Surgery, Okayama University Medicine School

(Received 26 May 1997; accepted 26 June 1998)

Abstract: This study was carried out to evaluate the effectiveness of various forms of quadriceps isometric exercises to facilitate the activity of the medial vastus muscle over that of the lateral vastus muscle. Five quadriceps isometric exercises were studied in 15 healthy volunteers (15 limbs) and 11 patients (15 limbs) with disuse quadriceps muscular atrophy. The amplitude of the integrated surface-EMG was evaluated for the medial vastus, lateral vastus and femoral rectus muscles. The quadriceps setting exercise in conjunction with isometric contraction of the hip adductor muscles in the foot-supinated standing position demonstrated the highest value in the ratio of medial vastus to lateral vastus muscle activity (VM/VL). It was found that this quadriceps isometric exercise facilitates the activity of the medial vastus muscle over the lateral vastus muscle.

Key words: quadriceps strengthening exercise, medial vastus muscle, closed kinetic chain exercise