Just because older people get stronger muscles doesn’t mean their legs get stronger — muscle size and leg strength don’t go hand in hand as we age.

Older people who start with less muscle in their legs, weaker legs, or are older in age tend to lose more leg strength over three years—even when you account for each factor on its own.

As people get older, their legs get weaker much faster than they lose muscle mass — so something else besides just losing muscle must be making them weaker.

For older people lifting weights, doing just one set of exercises builds just as much strength as doing four sets—so more sets don’t necessarily mean stronger muscles.

For older people, lifting weights once or four times a week might not make much difference in how much stronger they get—but it could make a big difference in how much their muscles grow.

Older women who lift weights—even just one arm or leg at a time—gain muscle and fight off the natural muscle loss that comes with aging.