Muscle Activation on Stable and Various Unstable Surfaces with Bodyweight and 30%1RM Weight during Deep Squat with Methods of RMS and Linear Envelope

The purpose of the study was to analyze and compare muscle activaty of leg and trunk muscles during deep squat on stable and various unstable surfaces with the method of RMS value and Linear Envelope for nineteen healthy male volunteers.No difference was in the RMS value and power mode of most selected muscles with bodyweight or 30%1RM weight during stable and unstable platform(hard bearing surface).The RMS value of some selected muscles,such as rectus abdominis,erector spinae,tibialis anterior,in variable condition changed,which differ from power mode.On the rubber disk,which is the soft support surfaces,the RMS value and power mode of some muscles were significantly changed.Most muscle activitation was greater as the external load increased in stable and the same instable state.