Use a glute-ham machine and lie down on your stomach in the apparatus. Make sure the machine is set up so that your knees are slightly bent. Bend at the waist over the mid-section pad until your upper and lower body is at a 90-degree angle. Then, using your glutes and hamstrings, lift up your upper-body until it is parallel with your hips. Then, lower your upper-body back down to the starting position. When working with just your body-weight, place your hands on the back of your head. When holding a weight plate, hold the plate against your chest, with your arms crossing over the plate and across your body.