Training one arm or leg at a time helps older women build muscle just as well as training both at once—but it doesn’t help them use both sides together any better.

Whether older women train one arm or leg at a time or both together, they both gain muscle—just as much as each other—and both are better than not training at all.

When older women train by pushing or pulling with both arms or legs at the same time, they get better at using both sides together, making their strength more efficient.

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.

If you train one leg at a time, that leg gets much stronger than the other when tested alone — but if you train both legs together, both legs get stronger at the same rate, with no one leg getting ahead.

When older women try to push with both legs at once on a leg press or pull with both arms on a lat machine, they’re weaker than when using each side separately—but this doesn’t happen when they extend their knees.