This exercise is used to strengthen the rear deltoid muscles, which are very important for other exercises like the bench press.
Begin by attaching a rope attachment to a low pulley machine. Then sit on the machine and grab the ends of the rope with your palms down; sit up so that your back is straight and slightly arched. Next, bend your elbows and pull your hands towards your neck; pull your elbows up and back at the same time. Continue this movement, until your hands are next to your ears and your elbows are out to the side. Also, your forearms will be pointed slightly upward in this position. Squeeze the muscles of your shoulders and back, and then return the weight to the starting position. Repeat this movement until you have completed your set.
Make sure to keep your elbows high throughout the movement, this will keep an emphasis on your rear delts.