According to American Council on Exercise-certified fitness professionals, squats are one of the most effective exercises for toning your lower body. Whether you use your own body weight or add resistance with hand weights, squats work most of the muscles in your lower body and help improve your balance. Although squats are an effective exercise for your quads, hamstrings and gluts, they must be done properly to avoid injury.
Primary Muscles Used
The primary muscles used in any squat are your quadriceps and hamstrings. These are the two large muscle groups in your thigh. The four muscles that comprise the quadriceps, known more commonly as the quads, run along the front of the thigh. The hamstrings are the three muscles running along the back of your thigh. Working together the quads and hamstrings allow you to flex the thigh and extend the leg. When lowering and raising in a squat, you can run your hands along your thighs and feel these muscles contracting and releasing to support your body. The other primary muscle used in a squat is the gluteus maximus, the largest muscle in your rear end.
Secondary Muscles Used
In addition to the large muscles of your rear end and lower legs, several other muscles are used to perform a squat. The soleus and gastrocnemius muscles in your calf support and balance you as you raise and lower in a squat or in any standing exercise. During a squat, your torso gets most of its support from the erector spinae muscle group and the transverse abdominals. The erector spinae are a group of muscles in your lower back, while the transverse abdominal muscles run along your sides from your ribs to your hips. Because the gluteus maximus rarely works alone, your other gluteal muscles -- the gluteus minimum and medias -- also get a workout when doing squats.
Even though large and small muscles help support you in a squat, you can injure yourself if a squat isn't performed properly. At the lowest point, your rear end should be in a flat line with knees or slightly above; your buns should never go lower than your knees. Another key point is to keep your knees from poking out over your toes when in the lowest position of the squat. Throughout the squat, your knees should stay in line with your ankles or the center of your foot. During the entire exercise, keep your back flat, not arched, and your abs tight to avoid straining your back. To get the most out of your squat sets and to avoid injury, make your movements slow and steady.
Squats have many variations depending on your fitness level and how hard you want to work. The basic squat is done with both feet on the floor and without weights. If you want to work your muscles a bit harder, you can hold hand weights by your sides or on your shoulders. People really wanting to build up their thigh muscles hold a weighted barbell across their shoulders. To add a calf boost to your squat routine, raise up onto your calves when you come back to standing from the squat. To improve balance and add a challenge, perform your squats on a single leg. The non-working leg can be raised or remain relaxed on the floor.