This exercise is a progressed version of a prone position body weight loaded scapular protraction/retraction exercise. It is progressed because it is a single arm version from atop a box. Having only 3 points of contact requires a greater effort in stabilizing through the midline and the shoulder. Regressed versions of this Single Arm movement include being done from the knees, rather than a full push up position, until rotation stability has been solidified. Basic requirements include solid scapular mobility with the strength ability to protract and retract , and a single arm plank hold. There are numerous exercises that are utilized to progress up to this level. This movement can be progressed further by adding a weight or banded component.