In just 2 weeks of not using their legs, young people lose a third of their muscle strength; putting their muscle strength at a level comparable to a person 40 to 50 years their senior, new research says. The research stems from a study conducted by the Center for Healthy Aging and the Department of Biomedical Sciences at the University of Copenhagen.

A university news release reports that researchers sought to examine what happens to the muscles in younger and older men after a period of high inactivity, by way of so-called immobilization with a leg pad.

Andreas Vigelsø, PhD, the Center for Healthy Aging and the Department of Biomedical Sciences at the University of Copenhagen, outlines the researchers’ findings.

“Our experiments reveal that inactivity affects the muscular strength in young and older men equally. Having had one leg immobilized for 2 weeks, young people lose up to a third of their muscular strength, while older people lose approximately one fourth. A young man who is immobilized for 2 weeks loses muscular strength in his leg equivalent to aging by 40 or 50 years,” Vigelsø says in the release.

The release notes that when immobilized for 2 weeks, young men lose 485 grams of muscle mass on average, while older men lose approximately 250 grams. It also states that the participants’ physical fitness was also reduced while one leg was immobilized in the pad.

Martin Gram, researcher at the Center for Healthy Aging and the Department of Biomedical Sciences, points out that the more muscle mass an individual has, the more they will lose.

This means, “if you’re fit and become injured, you’ll most likely lose more muscle mass than someone who is unfit, over the same period of time. But even though older people lose less muscle mass and their level of fitness is reduced slightly less than in young people, the loss of muscle mass is presumably more critical for older people, because it is likely to have a greater impact on their general health and quality of life,” Gram says.

The release reports that following 2 weeks of immobilization, the participants bicycle-trained three to four times a week for 6 weeks. Yet Vigelsø states that unfortunately, bicycle training was not enough for the participants to regain their original muscle strength.

“Cycling is, however, sufficient to help people regain lost muscle mass and reach their former fitness level. If you want to regain your muscular strength following a period of inactivity, you need to include weight training,” Vigelsø adds.

[Source: University of Copenhagen]