If you're new to working out, doing leg exercises for 10 weeks can make one of your big thigh muscles grow bigger, even if the individual muscle fibers don't get thicker.

When untrained men get stronger in a static leg press, the main reason is that their thigh muscle near the hip gets bigger and its fibers angle more, which helps push harder.

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 new to strength training, having more tiny blood vessels around your fast-twitch muscle fibers might help those muscles grow more when you start working out.

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.

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.