Delayed onset muscle soreness: Lack of effect of therapeutic ultrasound in humans

Objective: To investigate the effects of two dosages of pulsed ultrasound therapy (1MHz, spatial averaged peak intensity 0.8W/cm(2), mark space ratio of 1:4) on acute-stage delayed onset muscle soreness (DOMS). Design: Double-blind, placebo-controlled, randomized trial. Setting: Laboratory of a university physiotherapy department. Participants: Forty-eight healthy volunteers (24 men, 24 women) with no arm pathology or pain at the time of the study. Interventions: Subjects were randomly allocated to one of four treatment groups: control, placebo (sham insonation), low-dosage pulsed ultrasound (mean dosage 172.8J), or high-dosage pulsed ultrasound (mean dosage 345.6J). DOMS was induced in the nondominant elbow flexors in a standardized fashion through repeated eccentric exercise until exhaustion. Main Outcome Measures: Elbow extension, flexion, and resting angles (universal goniometer), pain (visual analogue scale), mechanical pain threshold/tenderness (pressure algometer), and a McGill pain questionnaire. Measurements were taken before and after treatment each day except for the McGill pain questionnaire, which was completed at the end of the trial. Results: Significant differences were seen between groups in relation to range of flexion (p = .0032), with the control group losing least range of flexion. There were no other significant differences between the groups. Conclusion: No convincing evidence was found to support the use of pulsed ultrasound therapy in the management of DOMS at the parameters discussed here. (C) 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.