Doing around 31 sets per muscle group each week is the sweet spot for building muscle, and doing more than that won't give you noticeably better results.

If you're a guy who already works out regularly, doing 5, 10, 15, or even 20 sets of exercises per muscle group each week won't make your muscles grow any bigger than the others—after 6 months, they all end up looking about the same.

If you're already used to lifting weights, doing just a few sets per week — but pushing each set to your max — builds the same amount of muscle as doing a lot more sets.

We don't currently have enough proof to say whether working out a specific muscle group three times a week builds more muscle than doing it twice a week. Because the research isn't clear on this, experts can't yet recommend training muscles more than twice weekly for growth.

If you lift weights, your muscles grow bigger — but only up to about 45 sets a week per muscle group; after that, you don’t get much extra growth no matter how much more you train.

Everyone’s body responds differently to workouts—what works wonders for one person might be too much or too little for another, because of differences in genes, energy use, and how fast they recover.