Stand in front of a chair, facing away from it, with a dumbbell gripped vertically in both hands at chest height. Feet should be just wider than shoulder-width with your toes slightly turned out. Brace your core and keep your chest up. Bending at the knees, drive your hips back and down. Lower slowly with control until your glutes touch the chair, inhaling as you do so. Pause at the bottom, then push through your feet to extend your legs and drive your hips forward to return to the start position, exhaling as you do so.