If you're an older adult who got stronger from light weight training, doing more sets might help you build even more muscle—but we're not as sure about this as we are for people who didn't respond to the light training at all.

If you're an older adult who's already seeing some muscle growth from light weight training, doing more sets might help you build even more muscle—but the extra gain isn't big enough to be sure it's real and not just luck.

If older people don’t get stronger from doing just one or two sets of weight exercises, doing four sets might help them build more strength—but it doesn’t work as reliably as it does for making muscles bigger.

For older people, doing four sets of weight exercises instead of just one can help build more muscle—but only if their body is already somewhat responsive to exercise; if it’s not responsive at all, more sets don’t help.

If you're an older adult who's already getting stronger from light weight training, doing even more weight training might help you build even more muscle—but not as much as it helps people who didn't respond to light training at all.

If older people who didn’t get stronger from doing just one set of weight exercises start doing four sets instead, they’ll likely grow bigger muscles in their thighs after 10 weeks of working out twice a week.