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.

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.

Even doing a huge number of leg sets—over 50 a week—didn’t make anyone’s muscles shrink, which means there might be a very high limit to how much training your muscles can handle without losing size.

You don’t need to train every day—just twice a week for two months can make your upper and middle thighs bigger, as long as you do enough total work.

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.

If you're already fit and lift weights, doing 5 to 20 sets of exercises for each muscle group every week won't make you grow bigger muscles any more or less than any other number in that range.