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.