HOW: Place a resistance band above the rig. The thicker the resistance band, the more support you will have. Use heavy weights on the barbell, and set it up behind the rig. Place a sleeve over the barbell as well as a soft surface under the barbell to cushion your knees. Put your body through the band. Place your ankles under the barbell against the cushion. Slowly lower yourself to the ground, using your arms only if necessary, and drive yourself back up by trying to bring your butt to your heels.
FEEL: You will feel your hamstring muscles working very hard with this exercise. You will also feel your core muscles working to keep your trunk in a good position.
COMPENSATION: Do not round or bend your back. You should be able to draw a straight line from your knees to your forehead.