A lunge is a fundamental lower-body exercise that involves stepping one leg forward and lowering your body until both knees are bent at roughly 90-degree angles, then pushing back to the starting position. Lunges strengthen your quadriceps, glutes, and hamstrings, and are a functional movement found in daily activities like climbing stairs or walking. To perform a standard lunge, stand upright, step forward with one leg, lower your hips, and then push through your front foot to return to the start.