1. Secure your feet against the back plate of the apparatus and rest the middle of your thighs on the pad. Keeping your lower back in its natural arch, straighten your knees, lowering your body toward the floor. Stop when you feel your back is about to lose its arch. Tuck your chin to your chest and explode back upward, bending your knees and pulling with your hamstrings to raise your body straight and vertical. That's one rep. Use a spotter at first, as beginners can find it difficult to complete even one rep. Try to get strong enough that eight reps is no challenge.