If you're new to lifting weights, doing a moderate amount of workouts each week will make you stronger faster than doing very few workouts — and you'll keep getting stronger week after week for the first 9 weeks.

If you're new to weight training, doing three sets of each exercise instead of just one will help you get stronger faster — and after about nine weeks, the difference becomes even bigger.

If you're already fit and lift weights, doing 5 to 10 sets per muscle group each week will make you stronger—but doing more than that (like 15 to 20 sets) won't make you any stronger, no matter how hard you push.

If you're already experienced with weight training, doing 5 to 10 sets per muscle group each week builds just as much muscle and strength as doing 15 to 20 sets—so going over 10 sets won't give you extra gains.

If you're already fit and lift weights, doing anywhere from 5 to 20 sets per muscle group each week will make you stronger and build more muscle — and it doesn't matter much which number you pick within that range.

Lifting weights more often helps you get stronger, but after a certain point, you don’t get much stronger no matter how much more you lift—plus, this slowdown happens sooner for strength than for muscle growth.