Stand with your feet shoulder-width apart, toes pointing slightly out. Push your hips back and bend your knees to lower yourself down, extending your arms forward for balance, until your thighs are about parallel to the floor. Drive through your heels to stand back up. Sit back like there's a chair behind you that someone may or may not have moved - hips lead, knees follow, heels never leave the floor.

Works: quads, glutes, hamstrings, calves

Breathing: Inhale as you lower, exhale as you drive back up.

Common Mistakes: Letting the knees cave inward on the way up, lifting the heels and tipping onto the toes, and folding the chest forward instead of sitting the hips back.

Make Easier: Reduce the depth with High Squats, or hold onto a wall or chair for support as you sit back.

Make Harder: Pause for a 2-count at the bottom of every rep, add explosive power with Jump Squats, or work toward single-leg strength with Pistol Squats.