Delayed onset muscle soreness: lack of effect of therapeutic ultrasound in humans.

OBJECTIVE: To investigate the effects of two dosages of pulsed ultrasound therapy (1 MHz, spatial averaged peak intensity 0.8 W/cm2, 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 172.8 J), or high-dosage pulsed ultrasound (mean dosage 345.6 J). 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.