Even if you do a lot of leg workouts, your thigh muscles grow about the same amount whether you do 20 or 50 sets a week—just doing any consistent training makes them bigger.

If you're a young man who already trains regularly, doing more sets with lighter weights for 6 weeks can make your thigh muscle grow a little bigger — but doing fewer sets with heavier weights won't make it grow at all.

Doing a lot more leg workouts—over 50 sets a week—doesn’t make your thigh muscles grow bigger than doing 20–40 sets a week, even if you train for 12 weeks.

Doing more weightlifting each week helps you build more muscle—but only up to a point. After a certain number of sets, doing even more doesn’t help much more.

When people who already lift weights train with different methods—like starting light and going heavy, or doing sets to failure—all of them get about the same muscle growth if they do the same total amount of work.

Even though the guys doing the most workouts looked like they might have grown a little more, the difference wasn’t big enough to say for sure that more sets = more muscle.