This movement is performed with a hyperextensions bench.
Position your body in the hyperextensions bench so that your hips or on the pad. You should be able to freely move up and down without and restriction.
Start with your body extended down, do no hang all the way down.
Raise your body up so that you are parallel to the ground. Or until your feel a contraction in your lower back.
Hold for 1-2 seconds, then lower slowly back down.
For more resistance, you can hold a weight close to your chest during the movement for a greater challenge.
Search on FreeTrainers.com