Electromyographic analysis of the hamstring muscles during bicycle ergometry

Abstract

Electromyographic (EMG) analysis performed on a sample of 20 non-competitive male cyclists between the ages of 18 and 36 was utilized to compare the effect of the upright versus forward-lean position of the trunk on hamstring muscle activity during bicycle ergometry. The peak and summated EMG values, expressed as a percentage of maximal voluntary isometric contraction, were recorded continuously during a 45-second testing period in which subjects changed from the upright to forward-lean positions every 15 seconds. Paired t tests revealed significant differences between the upright and forward-lean positions (p <.001) in both the peak and summated activity levels. Pearson product correlation coefficients showed no significant correlation between angle of sacral tilt and EMG activity. It was determined that the forward-lean position significantly increased hamstring activity and that angle of sacral tilt is not noticeably correlated with EMG activity. Further research is necessary analyzing EMG activity to find optimum angle of sacral tilt for maximum hamstring output and to measure peak differences in trunk positions using different angles of sacral tilt.