The single-leg squat strengthens the entire lower body, emphasizing the quads, hamstrings, and glutes. It also improves stability, balance, and core strength.
Stand tall on a bench or box that's about knee height. Hold your arms straight out in front of you.
Lift one leg out in front of you. Balancing on the opposite leg, bend your knee and slowly lower your body until the heel of the extended leg lightly touches the floor. Pause, then push yourself back up to the starting position.
Do not let the squatting knee turn inward.
Keep your supporting foot firmly planted, making sure not to let your heels lift off of the floor.