Sit on seat and grasp stirrup to one side. Position elbow out to side, slightly lower than shoulder height. Position hand slightly narrower than elbow width, in front of upper arm. Lean forward in seat.
Push stirrup out in front of upper chest while turning torso away from pulley. Return stirrup and torso back to original position allowing torso to rotate back until slight stretch is felt through chest, shoulder or waist. Repeat.
The effective range of motion of Pectoralis Major is only about half of what it is in non-twisting movement.