If you slowly add more sets to your leg workouts every two weeks, you’ll get stronger in the squat than if you keep doing the same number of sets the whole time.

If you're already strong and lift weights, training each muscle group either once or five times a week for eight weeks will give you about the same strength gains on the bench press, squat, and row.

If you're already strong and lift weights regularly, doing 10–15 hard sets per muscle group each week for 2 months will make you stronger and add a little muscle — whether you train your whole body every day or just once a week.

If you're already fit and lift weights, doing way more sets (15–20 per muscle group per week) doesn't make you stronger faster—in fact, you might even gain less strength than if you stick to just 5–10 sets.

For guys who already lift weights, doing short bursts of heavy lifts with brief rests in between can help them lift a little more weight after 8 weeks than doing regular sets, even if they do the same total amount of work.

If you're already experienced with weightlifting, doing rest-pause sets (short breaks between reps) for 8 weeks might help you lift a little more weight in squats than doing regular sets, but not better than drop sets.