Never allow your knees to track out over your toes during this movement. Doing so will place undue stress on the knee joints.
This exercise requires a good deal of balance and is not recommended for those with balance issues.
Keep your head up and back straight throughout the exercise. Never allow your back to round.
Instructions
Load a barbell with the appropriate amount of weight and position the bar so that it is resting on the muscles on the top of your back, not on the back of your neck.
The bar should feel comfortable. If it doesn't, try adding some padding to the bar. Now take your hands over the back and grip the bar with a wide grip for stability.
Stand with your back straight and a slight bend in your knees. Keep your head up, eyes looking forward and feet close together. You are now in the starting position.
Step sideways with your left leg while maintaining your balance and squat down through your hips.
Keep your torso straight and head up. Don't allow your knee to track out over your toes.
Push yourself back to the starting position by using your heal to drive you.
Repeat this movement with your right leg and then repeat for desired reps.