If you're already experienced with weight training, doing the exact number of sets your past logs suggest (1.2 times your usual) builds more muscle than doing a fixed number of 22 sets every week — and this is shown by measuring your thigh muscle thickness with ultrasound.

Higher weekly resistance training volume leads to greater muscle hypertrophy in trained individuals.

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.

People who already train regularly are more likely to see real muscle growth when their workout plan is customized for them, rather than using a one-size-fits-all routine — and the difference is about half as many more people seeing real gains.

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.

Doing more sets of weightlifting seems to build muscle more reliably than how close you get to failing on each set—whether you stop short or push to exhaustion doesn’t change the muscle growth much if you’re doing the same number of sets.