Position two aerobic steps a short distance apart, parallel to one another. Stand with one foot atop each with a dumbbell placed vertical in the centre of the two steps. Keep a flat back and bracing your core, reach down to grab hold of the dumbbell securely with both hands. Stand tall with the dumbbell between your legs. Brace your core and keep your chest up. Bending at the knees, drive your hips back and down. Lower slowly with control until your thighs are parallel to the floor, inhaling as you do so. Pause at the bottom, then extend your legs and drive your hips forward to return to the start position, exhaling as you do so.