Take a wide stance with your toes turned slightly out, bring your hands together at your chest and sink into a squat. Holding that depth, lift both heels off the floor, rising onto the balls of your feet, then lower the heels back down - all without your hips bobbing up so much as an inch. Your quads hold the fort while your calves do laps around it, and both will be filing complaints by the end of the set.

Works: calves, quads, glutes, inner thighs

Breathing: Exhale as the heels rise, inhale as they lower - keep it flowing through the hold.

Common Mistakes: Rising out of the squat with every heel lift, letting the knees cave inward as the legs tire, and rushing the raises instead of lifting and lowering with control.

Make Easier: Hold a shallower squat, rest a hand on a wall or chair for balance, or build up with standing Calf Raises first.

Make Harder: Sink deeper into the hold and pause for a 2-count at the top of every raise, or finish each set with Jump Squats while the legs are already burning.