Ten volunteers (19-23 years old) performed 9 sets of 12 bilateral knee-extension exercises at 60% 1RM. Following exercise, 4 ultrasound treatments (5-cm transducer head, 1.0-MHz frequency, pulsed mode at 1.0 W/cm2) were applied for 8 min daily to the quadriceps muscle of a randomly selected treatment leg. The placebo leg received similar treatment with the ultrasound apparatus turned off. Knee-extension peak torque values and delayed onset muscle soreness (DOMS) were assessed on each leg prior to exercise and at 20 min and 24, 48, 72, and 96 hr postexercise. Postexercise peak torques declined to 60-70% of preexercise values and returned to normal by 96 hr. DOMS sensation peaked 24 hr postexercise and diminished thereafter. No significant differences in peak torque or DOMS were noted between ultrasound- or placebo-treated legs at any time postexercise. Hence ultrasound, as applied in this study, does not appear to be effective in enhancing postexercise muscle strength recovery or in diminishing DOMS.
Carrie Plaskett, Peter M. Tiidus and Lori Livingston
Peter M. Tiidus, Joel Cort, Sarah J. Woodruff and Pamela Bryden
To evaluate ultrasound’s effectiveness after eccentric-exercise-induced muscle damage.
Random assignment to ultrasound (UT) or placebo (PT). Ultrasound was applied immediately and 24, 48, and 72 h after 50 maximum eccentric contractions of the biceps.
Concentric and eccentric peak torques, resting elbow angle, and subjective muscle soreness were measured before and 24, 48, 72, and 96 h afterward.
No significant differences between UT and PT for biceps concentric or eccentric peak torque were noted. Both groups exhibited significant (P < .01) depression in eccentric and concentric peak torques with a slow return toward preexercise values over 96 h. Resting elbow angles for both groups were significantly lower than preexercise values up to 96 h (P < .01). Muscle soreness increased significantly (P < .05) at 24 and 48 h and returned to preexercise levels by 96 h.
Daily ultrasound did not influence recovery after eccentric-exercise-induced muscle damage.