Older adults have to exercise more than younger adults in order to maintain their muscle mass.
To examine how much exercise was needed to maintain or increase muscle mass, size and strength in adults aged 20 to 35 years and ages 60 to 75, researchers assigned all participants three sets of resistance training exercises (leg press, knee extensions and squats) three times a week. In the 32-week second phase, participants were divided into three groups: some were assigned to stop resistance training altogether, some were told to reduce training to one day a week, and others were asked to cut down training to one day and one set of resistance exercises (as opposed to three sets) a week.
It was found that in the younger adults, muscle size was maintained in both groups that reduced their training. This was not the case in the older adults, whose muscle size shrank even if they did one to three sets of the exercises one day a week. However, one day of resistance training a week was enough for both younger and older adults to maintain their strength.
The study is the first to suggest that older adults require greater weekly maintenance exercise than younger individuals to maintain resistance-training-induced increase in muscle mass.