Nonthermal ultrasound and exercise in skeletal muscle regeneration

Arch Phys Med Rehabil. 2005 Jul;86(7):1304-10. doi: 10.1016/j.apmr.2004.12.037.


Objective: To determine whether continuous nonthermal therapeutic ultrasound (US) and low-intensity exercise (Ex) influence skeletal muscle regeneration after a standardized contusion injury in an animal model.

Design: Randomized controlled trial with blinded comparisons in a 2 x 2 factorial (US by Ex) design.

Setting: Animal care facility and exercise physiology biochemistry laboratory.

Animals: Twenty male Wistar rats (age, 8 mo) received a reproducible bilateral contusion injury to the gastrocnemius muscles. Ten gastrocnemius muscles from 5 noninjured, nontreated rats provided baseline control data.

Interventions: US (continuous duty cycle, 3 MHz; intensity, 0.1 W/cm2 ; transducer, 1cm2 ; duration, 5 min/d; duty cycle, 100%) and exercise (20 min/d of low-intensity treadmill walking at 14 m/min). Gastrocnemius muscles from injured rats received exercise treatment alone (Ex + NoUS), exercise and US treatment (Ex + US), US treatment alone (NoEx + US), and no treatment (NoEx + NoUS).

Main outcome measures: Ninety-six-hour postinjury muscle mass, contractile protein concentration, fiber cross-sectional area, number of nuclei per fiber, and myonuclear density.

Results: Myonuclei per fiber were statistically greater in injured than in noninjured gastrocnemius muscle (P < .05). There were no statistical differences (P > .01) among the 4 injured treatment groups for any of the outcome measures chosen as biomarkers of skeletal muscle regeneration.

Conclusions: There is no evidence that the specific continuous US and Ex protocols investigated enhanced skeletal muscle regeneration after contusion injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Contractile Proteins / metabolism
  • Contusions / physiopathology
  • Contusions / therapy*
  • Male
  • Models, Animal
  • Muscle Fibers, Skeletal / cytology
  • Muscle, Skeletal / injuries
  • Muscle, Skeletal / physiology*
  • Physical Conditioning, Animal / physiology*
  • Random Allocation
  • Rats
  • Rats, Wistar
  • Regeneration / physiology*
  • Ultrasonic Therapy*


  • Contractile Proteins