Pain complaint and muscle soreness associated with high-voltage electrical stimulation: effect of ramp time.

The purpose of this study was to determine the effects of ramp time on subjects' perception of discomfort/pain and muscle soreness associated with high-voltage electrical stimulation. 31 female students were randomly assigned to three treatment groups, each of which was assigned a different ramp time (1.0, 3.5, and 5.0 sec.). The subjects' wrist and finger flexors were stimulated with ElectroStim 180-2 unit using the bipolar electrode arrangement. During the stimulation, the subjects rated their experience of discomfort/pain at the threshold of sensory stimulation, the threshold of motor stimulation, and maximum tolerance of painful stimulation. The session was terminated after 10 tetanic isometric contractions. The subjects were instructed to rate their soreness, 24- and 36-hr. poststimulation using a 10-point ratio scale. A significant F ratio was noted for discomfort/pain perceptual levels but not for ramp time. Scheffé's post hoc analysis showed that the discomfort increased as the current intensity was increased. The F ratio for ramp time and time frame (24- and 36-hr. poststimulation) was not statistically significant for the ratings of muscle soreness. The findings suggest that the patients's complaint of pain and muscle soreness associated with high-voltage electrical stimulation is not affected by the rate of rise of current.