By Nathan Seppa
Offering a modern take on an age-old remedy, scientists report that the satisfaction one gets from rubbing sore muscles seems to have tangible roots. Massages might lessen pain-inducing inflammation in muscles and boost healing in the process.
Researchers from Ontario and California have found clear molecular signs that overworked muscle cells respond to being manipulated by massage. They also found measurable decreases in inflammatory compounds in massaged muscle tissue and indications that muscle cells rev up their energy processors for the inevitable repairs that follow hard exercise. The findings appear in the Feb. 1 Science Translational Medicine.
“This is the best data I’ve ever seen addressing possible mechanisms by which this therapy works,” says Thomas Best, a sports medicine physician at the Ohio State University School of Medicine. “This is very compelling.”
Justin Crane, a kinesiologist at McMaster University in Hamilton, Ontario, and his colleagues recruited 11 active men to participate in an exhaustive workout that taxed their quadriceps, the muscles at the front of the thigh. Shortly afterward, one thigh on each volunteer received a 10-minute massage and the other didn’t. The researchers then took a muscle biopsy from both legs of each volunteer right after the massage and again 2.5 hours later.
Strenuous exercise damages muscle tissue, followed by rebuilding or disposal of damaged muscle cells, Crane says. While inflammation routinely shows up immediately after such hard exercise, lingering inflammation hinders the repair process.
The biopsies taken immediately after massage showed that the muscles of the massaged legs, but not the untreated legs, had reduced levels of an inflammatory protein called tumor necrosis factor-alpha. The biopsies also revealed activation of two kinds of enzymes called kinases right after the massage, an indicator that the muscle cells responded to being manually manipulated, Crane says.
The massaged-leg biopsies taken 2.5 hours later showed reduced levels interleukin-6, a different inflammatory protein, and elevated concentrations of a multipurpose compound called PGC1-alpha. PGC1-alpha plays roles in muscle fiber maintenance and cell metabolism.
The analysis also hinted that muscle cells in the massaged legs were setting the stage for growth of mitochondria, the energy factories in cells. Such growth would facilitate muscle refurbishment, Crane says.
Although massage and other alternative medicines are used by millions of people, the therapies have doubters, in part because studies of these techniques often measure benefits subjectively or lack biological evidence of an effect, the authors note. “I’m more convinced now that massage is effective,” Crane says. “We see inflammation going down and, conversely, other cell signaling going up — two facets of rehab going the right directions.”
Whether these biological changes account for all of massage’s pain relief remains unclear. Lowering inflammation can reduce pain. But Crane says massaging sore muscles might also involve the release of pain-alleviating endorphins and other neurotransmitters. “We really have no idea,” he says.
The study casts doubt on one other theory: Lactic acid builds up in hard-worked muscles, and some people believe massage moves it out of the muscle. But the massaged legs showed no difference in lactic acid from the untreated legs.
