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When most of us get a massage, we leave in a trance with muscles feeling like jelly. But when Mark Tarnopolsky, Professor of Pediatrics in the Department of Medicine at McMaster University, got a massage — as part of a therapeutic regimen for a hamstring injured while waterskiing — he left determined to figure out exactly what was happening in his muscles at the molecular level to make them feel like jelly. His results are reported in Science Translational Medicine.
Scientists recruited eleven healthy male volunteers to exercise “to exhaustion,” for 70 minutes on a stationary bike, and then submit to a 10 minute massage in one leg. Muscle biopsies were taken from both quadriceps immediately after the massage and then again two and a half hours later. Biopsies were also taken at rest, on a separate day when the volunteers had not exercised.
First, the researchers confirmed that the exercise was sufficient to cause damage to skeletal muscle by searching for, and finding, tears in the muscle structure. After ten minutes of massage they found that muscles in the massaged leg had activated proteins that are involved in cellular responses to stretching and other mechanical stimulation. They suggest that these proteins enable the mechanical stimulus of the massage to be transmitted through the skeletal muscle. At this ten minute mark they also found a decrease in the amount of nuclear factor Kappa-B (NF-kB, consisting of subunits NFKB1 and NFKB2) in the nucleus. NFkB is an important regulator of inflammation, and it must be in the cells’ nucleus to exert its effects. This is a significant finding because muscle pain is caused primarily by inflammation.
Two and a half hours later, they found increased expression of proteins involved in tissue repair, metabolic fitness and recovery, and the formation of new mitochondria, which has a protective effect on the cell. The levels of inflammatory cytokines were diminished in the massaged leg, and proteins normally associated with cellular responses to stress from injury were not as highly activated as in the non-massaged leg. Interestingly, massage did not impact muscle glycogen or lactate levels, which rise with exercise. However, they did observe changes in the expression levels of some new genes with unknown functions.
The authors conclude by noting that in reducing levels of inflammatory cytokines, massage alleviates muscle pain in the same fashion as analgesics, such as the nonsteroidal anti-inflammatory drugs (NSAIDs) that comprise the most commonly consumed drugs in the world. With fewer side effects (other than a higher cost in both time and money), massage might thus be a good alternative to these drugs.
Crane et al. Massage therapy attenuates inflammatory signaling after exercise-induced muscle damage. Sci Transl Med. 2012 Feb 1;4(119):119ra13.