Here’s a rundown of the health benefits of doing squats, when and how to add them to your exercise routine, and how to do them correctly.

What Muscles Do Squats Work?

Why do fitness trainers love to prescribe squats? “Not only is the squat a fundamental movement pattern that has functional carryover to many activities of daily living and sport, it also challenges and strengthens many muscles,” says Tony Ambler-Wright, CSCS, product manager and master instructor for the National Academy of Sports Medicine (NASM) and a coach at the performance training center Movement Edge, who’s based in Roswell, Georgia. There are three categories of muscles involved in a squat. They include the gluteus maximus, the largest muscle in your butt; the quadriceps muscles, which include the rectus femoris, vastus lateralis, vastus medialis obliquus, and vastus intermedius; and a deep calf muscle called the soleus. There are also helper muscles, like those in the inner thighs, hamstrings, back, and calves, while stabilizers, which help you maintain proper form, include your abdominals and inner and outer thighs.

What Are the Benefits of Doing Squats?

Here are five:

Are Squats Safe for Everyone?

Squats are safe for most people. Yet there are some caveats. “There may be variations that may be less appropriate for certain individuals, depending on their medical and injury history, training history and status, and goals,” Ambler-Wright says. Variations of squats include: the pistol squat, the overhead squat, a jump squat, a goblet squat, and a box squat. The key is finding a squat variation and progression you can do without pain or risk of a particular condition worsening or injury risk increasing. For instance, if you have a knee or hip injury, you might need to modify how wide you stand or how deep you squat, Ambler-Wright says. Pregnant women may also have to modify the move. If you’re unsure, check with your doctor before doing squats.

How Many Squats Should You Be Doing and How Often?

The Physical Activity Guidelines for Americans (PDF) recommends that adults do strength training of all major muscle groups two or more nonconsecutive days a week. Yet how often you do squat and how many you do will depend on many variables, including how intense the squat is, what variation you’re doing, what your goals are, what your current fitness level is, and how much rest and recovery time you’ll need, Ambler-Wright says. The American College of Sports Medicine (ACSM) (PDF) recommends doing one set of 8 to 12 repetitions if you’re healthy, but you may want to do more if you’re trying to build muscular endurance or less if muscular strength is your goal. You can do total-body strength workouts or do upper body strength one day, lower body the next, according to ACSM. Whether you do squats (and leg workouts) on the days you’re doing cardio will depend on your fitness program and goals.

How to Do a Squat Correctly

Learning the right squat form will help prevent injury and ensure you’re using your muscles effectively. Follow Ambler-Wright’s instructions for basic, bodyweight squat: