QUADS & GLUTES: Dumbbell Squat works quads (and when low enough, the butt, the hamstrings, & lower back) 1. Holding dumbbells at sides, stand upright with your feet shoulder width apart. 2. Bend from knees until thighs are almost parallel to the ground (avoid letting knees turn inwards). 3. Keep back flat, lower back slightly arched inwards and head up. 4. Return to upright position and repeat.