Researchers from McMaster University, working with collaborators from the US, UK, and other Canadian universities, have discovered the genes which are responsible for some people to gain muscle and others don’t.
Their study is published in the journal Cell Reports.
The Natural Sciences and Engineering Research Council of Canada and the UK Medical Research Council provided grants to the study.
The findings are significant as they will provide clues to how to keep seniors healthy and safe.
Researchers compared the genetic responses of muscles in the two legs, and found what drives exercise-related muscle growth.
The key appears to lie in a set of 141 genes that regulate growth of the body’s skeletal muscles. Tethered to the skeleton by tendons, they are the muscles that control power and movement.
Throughout the experiment, participants built up muscle in one of their legs through a prescribed regime of weight training. For the first eight weeks of the study, the opposite leg served as a non-exercising control. For the last two weeks, the non-exercising leg was immobilized entirely with a brace to keep it from bearing weight.
The variation in muscle gain through weightlifting was consistent with results that the project’s supervisor Stuart Phillips, a professor of Kinesiology, had seen in 22 years of studying muscles at McMaster.
Muscle gains in the subjects’ active legs ranged from 1 to 15 per cent over the full 10 weeks, averaging 8 per cent, while muscle loss in their immobilized legs ranged between 1 and 18 per cent, averaging 9 per cent. In other words, the average subject lost muscle through inactivity at about five times the rate he had gained it through weightlifting.