LACK OF EFFECT OF TRANSCUTANEOUS ELECTRICAL NERVE-STIMULATION UPON EXPERIMENTALLY-INDUCED DELAYED-ONSET MUSCLE SORENESS IN HUMANS

The aim of the current study, for which ethical approval was obtained, was to assess the hypoalgesic efficacy of transcutaneous electrical n erve stimulation (TENS) upon acute stage (72 h) experimentally induced delayed onset muscle soreness (DOMS). TENS naive subjects (n = 48; 24 male and 24 female) were recruited, screened for relevant pathology a nd randomly allocated to one of four experimental groups: control, pla cebo, low TENS (200 mu sec; 4 Hz) or high TENS group (200 mu sec; 110 Hz). DOMS was induced in a standardised fashion in the non-dominant el bow flexors of all subjects by repeated eccentric exercise. Subjects a ttended on three consecutive days for treatment and measurement of elb ow flexion, extension and resting angle (Universal goniometer), Mechan ical Pain Threshold/tenderness (algometer) and pain (Visual Analogue S cale (VAS)) on a daily basis, plus McGill Pain Questionnaire on the th ird day only. Measurements were taken before and after treatment under controlled double blinded conditions. Analysis of results using repea ted measures analysis of variance (ANOVA) and post hoc tests showed so me inconsistent isolated effects of high TENS (110 Hz) compared to the other conditions upon resting angle and flexion scores; no significan t effects were found for any of the other variables. These results pro vide no convincing evidence for any measurable hypoalgesic effects of TENS upon DOMS-associated pain at the stimulation parameters used here .