Activity patterns of the hamstring muscles during a lateral weight shift in the standing position

Abstract

In this study, we examined the relationship between the activity pattern of hamstring muscles and postural change of weight shift, in the standing position. We used surface electromyographic data from the medial gluteus medius, biceps femoris, and semitendinosus muscles of 10 healthy male participants. During exercise tasks, we observed two groups of participants: those who registered ankle dorsiflexion during lateral weight shift movements and those who did not. The former group registered an increase in hamstring muscle activity and the latter group registered no change. Similar to a previous study, an increase in gluteus medius muscle activity was detected along with the start of lateral weight shift. It appears that the biceps femoris muscle works to increase hip extension before semitendinosus muscle activity, causing a forward weight shift and dorsiflexion of the ankle joint during lateral weight shift in the standing position.