Set-up: Begin by lying face down on a lightly cushioned surface.
Movement: With a slight bend in the knee of the working leg, engage the glutes and hamstring, raising your heel into the air. Pause at the top of the motion, and return to the start in control.
Emphasis: Do not push the range of motion by hyperextending the lower back or bending the knee more. Simply flex as far as your glutes and hamstrings will allow, the return to the start.
Repetitions: Complete all repetitions on one side, then the other. This counts as one set.