Lie face down with your entire torso on a bench and the full length of your legs and hip joint off the end of the bench. Grip the bench firmly in both hands. Place the soles of your feet together and drive your knees apart. This is your start position. Focusing the tension in your glutes and keeping the soles of your feet glued together, drive your feet towards the sky. Pause for a count of one at the top, squeezing your glutes, before returning to the start position. Repeat.