You’ve heard the expression, “The bigger you are, the harder you fall.” With respect to muscle mass and strength, this statement is not far from the truth. No matter how strong or big you are, you lose muscle strength and mass with inactivity.
It takes only a couple of weeks of inactivity to lose hard-earned muscle strength, and it takes even longer to regain it, according to a recent study from the Center for Healthy Aging and the Department of Biomedical Sciences at the University of Copenhagen in Denmark. Being younger and stronger isn’t necessarily protective, either. The study found that young, physically fit subjects not only lost a significant amount of their muscle strength, but also significant muscle mass.
In the study researchers sought to determine the effect of retraining as rehabilitation after short-term leg immobilization in both young and older men. They measured leg strength, leg work capacity, leg lean mass, leg muscle fiber type composition, and the blood supply of each subject.
For two weeks, the 17 young and 15 older men kept their legs motionless. That was followed by six weeks of bicycle endurance training. In the two-week immobilization period, the young men lost about 30 percent of the muscle strength in their legs. Essentially, it was as if their legs had the same amount of muscle as much older men. The older group similarly lost about 25 percent of their leg muscle strength.
The study confirms that the more muscle a person has, the more they will lose if they are sidelined by an injury, illness, or a vacation.
Athletes have a good reason to fear time off, considering that by taking just two weeks off, it will take them six weeks to simply regain that muscle.
“The more muscle mass you have, the more you’ll lose. Which means that 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,” said exercise scientist Martin Gram in this press release.
Age is another contributing factor in retaining muscle mass. Muscle generally decreases with age, so it wasn’t surprising that this study found the young male group had approximately two pounds more muscle in each leg compared to the older male group. However, after two weeks of immobilization, the young male group lost over a pound of muscle mass, while the older male group lost about half of that.
“A young man who is immobilized for two weeks loses muscular strength in his leg equivalent to aging by 40 or 50 years,” said Andreas Vigelsoe, another author of the muscle study. “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.”
This study highlights once again how detrimental inactivity can be on the body’s muscle reserves, while confirming that it takes about three times the amount of inactive time to get muscle mass back.
What if some periods of inactivity are unavoidable? At times, athletes must deal with injury, illness, or unplanned events. To really offset any loss in muscle during these periods properly, see our previous article, “Nutritional Strategies for the Injured Athlete.”
Vigelso A, Gram M, Wiuff C, Andersen JL, Helge JW, Dela F. Six Weeks’ Aerobic Retraining After Two Weeks’ Immobilization Restores Leg Lean Mass and Aerobic Capacity But Does Not Fully Rehabilitate Leg Strength in Young and Older Men. Journal of Rehabilitation Medicine 2015;47:552-60.