Researchers say they may have worked out why there is a natural loss of muscle in the legs as people age - and that it is due to a loss of nerves. In tests on 168 men, they found that nerves controlling the legs decreased by around 30% by the age of 75. This made muscles waste away, but in older fitter athletes there was a better chance of them being 'rescued' by nerves re-connecting. The scientists published their research in the Journal of Physiology.
As people get older, their leg muscles become smaller and weaker, leading to problems with everyday movements such as walking up stairs or getting out of a chair.
Failure to expand the motor unit size to compensate for declining motor unit numbers distinguishes sarcopenic from non-sarcopenic older men [wiley.com] (open, DOI: 10.1113/JP275520) (DX [doi.org])