Rabbit study offers clues to massage benefits
Published by Reuters Online
Last Updated: 2008-08-26 12:46:44 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Massage helps people feel better after strenuous exercise by actually pushing the inflammation out of stressed muscles, new research in animals suggests.
Dr. Timothy A. Butterfield of the University of Kentucky in Lexington and his colleagues found "striking" differences between rabbit muscles that underwent massage-like loading immediately after exercise compared to muscles that weren't massaged. "The muscle was able to produce a greater force than the non-massaged control limbs and it also looked a lot better," Butterfield told Reuters Health in an interview.
Athletic trainers and physical therapists frequently use massage to help athletes recover muscle function, he and his colleagues note in their report in Medicine & Science in Sports & Exercise. But while people say they feel better after massage, little research has been done on what is actually happening within their muscles, Butterfield said.
To investigate, he and his colleagues developed an animal model of strenuous eccentric exercise, which requires muscles to contract and lengthen at the same time. Some examples of eccentric exercise include actions of the hamstrings and quadriceps when a runner decelerates, as well as spinal muscle movements that occur when a person carrying an object bends over to set it down, Butterfield explained.
The researchers used machines to move the lower limbs of anesthetized rabbits in a way that mimicked a human lifting very heavy weights. For people, the researcher said, this is the type of exercise that results in "really tight soreness, pain" in the muscles. Then one of each animal's legs was massaged with a computer-driven wheel immediately after exercise, while the other leg was not.
Mechanical tests found the massaged limbs recovered strength faster than the non-massaged limbs. And when Butterfield and his team examined the animals' muscles under a microscope, they found less swelling, inflammation, and tissue damage in the limbs that had been massaged. Massaged muscle also weighed 8 percent less.
Butterfield and his colleagues suggest that massage may lessen the movement of white blood cells into muscle tissue, which would in turn cut down on tissue damage by reducing oxidative damage these cells can cause. "However, this hypothesis requires further testing," they write, noting that the rabbit model used in the study isn't appropriate for "direct translation" to humans.
He and his colleagues are now planning additional research in humans to further investigate mechanisms of massage benefit, and animal studies to examine what's happening to massaged cells at the molecular level.
SOURCE: Medicine & Science in Sports & Exercise, July 2008.