Application of a New Muscle Exercise Device using Intermittent Sole Pressure Stimulation

[Purpose] The aim of this study was to determine the lower-limb muscle activities during muscle exercise using an on-the-bed muscle training device that utilizes the intermittent inflation of an oval rubber balloon placed against the sole. [Subjects and Methods] Ten healthy subjects were asked to adopt a semi-recumbent position with a flat oval chloridized polyvinyl balloon placed against the sole. The subjects were asked to extend both their legs when they felt the inflation of the balloon on their plantar surface. This exercise was defined as leg exercise against intermittent sole pressure stimulation (ExISPS). [Results] The root-mean-square (RMS)-EMG values of the vastus medialis during ExISPS in the semi-recumbent position were similar to those when standing up from 45-degree knee flexion and calf-raising. The RMS-EMG values of the biceps femoris showed no significant difference among these exercises. The RMS-EMG values of gastrocnemius medialis during ExISPS in the semi-recumbent position were higher than those when standing up from 45-degree knee flexion and standing up from a chair. [Conclusion] The findings of this study suggest that the muscle activities during ExISPS mimic or are greater than those required of the leg in daily life.