Changes in lower limb muscle activity based on angle of ankle abduction during lunge exercise

[Purpose] This study compared the activity of the quadriceps femoris muscle according to the angle of ankle abduction during a lunge exercise. [Subjects and Methods] Fifteen male healthy volunteers participated in the study. All participants performed the lunge exercise with different angles of ankle abduction (0°, 20°, 40°, 60°). The activity of the rectus femoris (RF), vastus lateralis (VL) and vastus medialis oblique (VMO) muscles were recorded for the four angles by using a surface electromyography system. [Results] There were significant differences between the rectus femoris (RF), vastus lateralis (VL) and vastus medialis oblique (VMO) with every angle of the ankle joint. The most significantly increased muscle activity was evident in the vastus medialis oblique (VMO) when the ankle abduction was 60°. [Conclusion] These findings suggest that as the ankle abduction angle increases during the lunge exercise, the muscle activity of the quadriceps femoris muscle increases and this could be helpful in the selective muscle strengthening of the vastus medialis oblique muscle (VMO) with the ankle in the 60° abduction position.