Squats work nearly every large muscle in your lower body. Body weight or air squats primarily work your lower body muscles, while weighted squats work not only your lower body but also specific muscles in your upper body. No matter how you choose to practice your squat workout, you'll be sure to walk away with firmer legs and tighter, rounder gluteal muscles.
Hips
The squat is one of the best exercises for developing the shape of the gluteal muscles that make up your posterior hips. The gluteus maximus, the major extensor of the thigh, is the primary muscle in the hips worked during a squat.
Legs
A squat works your quadriceps, hamstrings and adductor muscles. Your quadriceps work to extend and stabilize your knees, important when performing squats. Hamstrings mainly flex your knees as well as extend your thighs in the upward phase of the squat. The wider your squat stance, the more extensively your adductor muscles, located on your inner thighs, are used. Your calf muscles, gastrocnemeus and soleus, are used to a lesser extent while doing a squat. These muscles primarily stabilize your knees and ankles.
Back
Though not a target body part, back muscles come into play when performing weighted squats. Your erector spinae muscles are the prime movers of back extension. These muscles contract continuously to support your torso and spine while bearing the extra weight used during your squats.
Abdomen
The rectus abdominis and transverse abdominis muscles of your abdomen also help support your spine and upper body when performing a weighted squat. Both increase intra-abdominal pressure, or create a "block," important when working with heavy weights.
References
- "Strength Training Anatomy, Second Edition"; Frederic Delavier; 2006
- "Anatomy & Physiology, Second Edition"; Elaine N. Marieb; 2005
- American Council on Exercise: Barbell High Back Squat
