Downward movement phase;
Allow the hips and knees to slowly flex while keeping the torso-to-floor angle relatively constant.
Maintain a position with the back flat, elbow high, and chest up and out.
Keep the heels on the floor and the knees aligned over the feet.
Do not flex the torso or round the back.
Continue flexing the hips and knees until the thighs are parallel to the floor.
Do not accelerate the bar or relax the torso at the bottom of the movement.