A

Attach the center of a resistance tube to a sturdy object 2 feet above the ground. With an end of the tube in each hand, lie facedown on a stability ball so your rib cage is centered on it. Extend arms in front of you at shoulder height, palms facing down.

B

Draw right arm to your side as you raise torso slightly and twist to the right. Hold for 1 count, then return to start and switch sides to complete 1 rep.