Vibration effects on three measures of relaxation

The effect of vibrotactile stimulation on relaxation as measured by EMG recording of the frontalis and trapezius muscles and by subjective report was assessed. It was predicted that low-frequency vibrotactile stimulation (less than 70 Hz) would facilitate muscle relaxation when measured by both EMG frontalis and trapezius recordings and by subjective report. The participants (8 male and 8 female) were randomly assigned to split-plot, before/after design consisting of four between-subjects treatments and one within-subjects treatment (pre- and post-treatment). The between-subjects treatments were footrest vibration, backrest vibration, footrest-backrest vibration combined, and control. The within-subjects treatment included pre- and post-treatment levels. Results of repeated-measures analyses of variance on each set of data yielded a significant change from pre- to posttreatment condition on all EMG and subjective report measures of muscle tension except the control. The utility of using EMG as a measure of relaxation is discussed.