Stand with your feet shoulder width apart with a flat back and your core braced. Keeping your chest up, bend at the knees and drive your hips back and down like you're sitting on a chair. You can 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. Then with control, elevate your heels off the floor and maintain that position for the requirement amount of time.