Secure the center of the tubing in the doorjamb at chest level.
Engage abdominal muscles before beginning the exercise.
Think “archery”. Facing the door hold one handle in each hand. Step away from the door so that there is tension on the elastic when your arms are extended. Keeping your left arm extended pull your right arm to you chest as you rotate your hips and step back with your right foot. Return to the starting position and repeat on left side. Continue alternating sides.