Prolonged Reduction in Shoulder Strength after Transcutaneous Electrical Nerve Stimulation Treatment of Exercise-Induced Acute Muscle Pain

40 patients with exercise-induced delayed onset muscle soreness (DOMS) of the dominant shoulder were randomized to receive active transcutaneous electrical nerve stimulation (TENS), placebo TENS treatment (placebo) or no treatment. The primary outcome of interest was shoulder strength. Secondary outcomes included the change in pain (Visual Analog Scale; VAS), mechanical pain sensitivity, and shoulder disability (Disability of the Arm, Shoulder and Hand (DASH) score). Results from the trial found that at 48 hours following the fatigue protocol, shoulder strength was significantly lower within both the active TENS group and the placebo TENS group compared to the no treatment group. At 72 hours following the fatigue protocol, shoulder strength remained significantly lower in the placebo TENS group compared to the no treatment group, while no significant difference between the active TENS and the no treatment group was reported. With regards to the change in pain, mechanical pain sensitivity and shoulder disability, there were no significant differences observed between the three groups.