Set-up: Set your feet slightly wider than shoulder width, brace your stomach and establish a neutral spine posture. Raise your chest up and look forwards and slightly upwards.
Movement: Start the movement as if you were about to sit down, pushing your hips down and back. Descend as far as you can without excessive rounding of the back and without the knees caving inwards. Your hips should end up well below the height of your knees. At the bottom of the motion rise up onto your toes flexing your calves, and drive back up to the start position.
Emphasis: Brace through your core at all times and try to keep your spine neutral throughout the duration of the movement. Do not let your knees push far forward in front of your toes or cave inward on the movement.
Assists: Holding onto a railing or sturdy door can make the exercise easier and assist in reaching deeper ranges of motion with proper form.