"Mammalian skeletal muscle tissue is the same regardless of which species of mammal it is in,” says Steven Devor, the study's lead author and an assistant professor of exercise science education at Ohio State University.

He and his colleagues studied the effects of aerobic exercise - in this case, galloping on a treadmill - on small sections of skeletal muscle tissue taken from the limbs of retired racehorses.

The findings support a "use-it-or-lose-it” philosophy: After ten weeks of regular workouts, the horses' muscles showed fewer signs of damage caused by exertion, even after the horses worked out at their maximum capacity. The results apply to humans and are especially important for older adults, Devor stresses.

"We have to work at keeping muscle mass as we age, otherwise that mass wastes away," he says. "This weakness leaves a muscle more prone to injury even when it's the least bit exerted. Also, joints are less likely to break if the musculature surrounding them is strong. According to these results, aerobic exercise training improves the ability of aging skeletal tissue to resist injury."

Some minor muscle damage is normal after a new or a particularly difficult workout. The pain that often appears a day or two after such exertion is called delayed onset muscle soreness, or DOMS.

"The way to get rid of this kind of pain is to stay physically active," Devor said. "It's ironic, but muscles are most often injured during exercise. But muscles get stronger by repairing this damage."

The current study builds on experiments Devor previously conducted in rats - about ten years ago, he helped identify the mechanism that causes DOMS. He was part of a team that found that this damage happens when tiny sarcomeres pull apart as the muscle lengthens.

MEDICA.de; Source: Ohio State University