Some older people’s muscles grow when they lift weights, and others don’t — this claim says that changing how many times you lift can tell the difference between those who grow and those who don’t, based on how much their thigh muscle size changes after just one set.

If older adults do not gain muscle from regular weight training, doing more sets and reps might help them finally start building muscle.

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.

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, their thigh muscles will grow bigger — and this was measured with a detailed scan.

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.