Rounding the lower back: Its crucially important that you keep a straight back when you squat! You can ensure your back is straight by keeping eyes facing forward, chest out, shoulder blades back, and back arched. Keep your core muscles tensed throughout the movement to help hold your back in place.
Pushing from the balls of your feet: This puts unnecessary strain on joints and tendons. Always push up through your heels. Curling up your toes can help you get the technique right.
Leaning forward: This happens when your hip move up faster than your shoulders. To prevent this keep the rep timing slow and controlled and stick your buttocks out as you go down.
Knees come too far forward: When you squat down your hips should be dropping straight down, not coming forward. Using a light weight, perfect your form standing side on to a mirror.
Not squatting deep enough: Using squats to their full potential requires squatting down at least until your thighs are around parallel to the floor.
Knees in or out: Dont point your knees in or out when youre lowering or pushing the weight. This puts unnecessary strain on the knee joints.
Looking down: As soon as you look down your back rounds, simple as that.
Instructions
Set up for the smith machine squat by setting the bar to around shoulder height and loading the weight you want to use.
Stand under the bar with your legs around shoulder width apart.
Grasp the bar with a wide grip and position the center of the bar on top of the muscles on your back. The bar should not sit on your neck!
Keeping your back straight and eyes facing forwards and take the weight off the rack.
Take a slight step forward.
Keeping your eyes facing forwards with a straight back, slowly squat down until your thighs are parallel to the floor.
Pushing up through the heels, raise the the bar back to the starting position.