Start: Attach a stirrup hand to the high pulley and stand sideways to the weight stack. Grab the handle with your inside hand. Take a couple steps away from the stack and perhaps a step back; you want to start with tension in the cable so there's resistance throughout the movement. Pull your shoulders back, and place your free hand on your hip. Keep a slight bend your working elbow.
Finish: Bring the cable handle down and across your body in a wide, arching motion, without changing the angle in your elbow, Stop before your working shoulder pulls forward-you want your shoulders and hips to stay in the same position throughout. Pause, then slowly return to the starting position. Finish the reps with that arm, then turn around and repeat with the other.