Stand with your feet just less than shoulder width apart with a flat back and your core braced. Place a small plate under the heels of your feet. Keeping your chest up, bend at the knees and drive your hips back and down like you're sitting on a chair. You can either cross your arms over your chest or simultaneously bring your arms up and out in front of you to provide a counter-balance. 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.