If young, healthy guys do leg workouts twice a week for six weeks, they get stronger — and doing lighter weights for more reps works about as well as heavier weights for fewer reps, except for hamstring curls, where more reps seem to help more.

Lifting heavy weights at least twice a week, doing full movements for a few sets each time, and doing it early in your workout can help healthy adults get stronger compared to not exercising or doing other types of training.

If college guys who've lifted weights before do a specific 12-week workout plan—3 times a week, 8 exercises, 3 sets each—they'll get 25% stronger in their arms, based on how much they can lift in one go on a curl machine.

Whether you lift light weights many times or heavy weights fewer times—both can make you stronger in exercises like squats and deadlifts, as long as you push to exhaustion.

If you're a guy who lifts weights and gets close to failure—like stopping just 1 or 2 reps short—you'll get just as strong as if you pushed yourself to the absolute max. Over 10 weeks, both ways boost leg strength by 20–35%.

If young guys lift weights all over their body 3 times a week for 9 weeks, they'll get stronger — no matter if they switch up their exercises or stick to the same ones.