Although ultrasound is one of the most frequently prescribed treatments for one of the most common sport and athletic injuries skeletal muscle contusions there's really no good scientific evidence showing that it treats injured muscles effectively, said Steven Devor, the study's lead author and an assistant professor of sport and exercise sciences at Ohio State University.
Devor and his colleagues used ultrasound to treat contusion injuries inflicted on rats' gastrocnemius muscles the main muscle in the calf.
Ultrasound treatment didn't hasten healing at all, even when compared to injured muscles that weren't treated with ultrasound.
"It didn't make one bit of difference in the time it took the treated and non-treated calf muscles to heal," Devor said. "Millions of people receive ultrasound treatment every year for muscle injuries, with insurance companies usually covering the cost."
Ultrasound treatments can cost around $50 per 15-minute session.
The study appears in a recent issue of the International Journal of Sports Medicine.
The researchers dropped small weights about six ounces onto the gastrocnemius muscles of rats' right and left hind limbs. The impact created a contusion in each muscle.
"The injury is similar to what might happen to a field hockey player if she was struck in the calf with a hockey stick," Devor said.
The researchers treated one hind limb on each rat with ultrasound daily for seven days for five minutes per session. Ultrasound waves were transmitted through a small wand that was rubbed along the rats' limbs. The other limb, used as the control, was left to recover on its own. Rats were sacrificed at various points during the two-month study so that the researchers could evaluate how each gastrocnemius muscle was healing.
Contact: Steven Devor
Ohio State University