While many people carry out various exercises to improve their deltoid muscles, there can be a tendency to ignore the rear deltoids. The Cable Rear Delt Fly is an exercise which focuses specifically on the rear deltoids. As the name suggest, this involves a weightlifting cable machine which you should set about shoulder height. The reason you set it at shoulder height is to ensure that the main focus is on the rear deltoids and not the traps or lats. Using a crossover position, in the shape of an X, pull the handles away and as you get as far as possible stop for a moment and feel your deltoids working. Slowly return back to the starting position, slowly working backwards is as important as the initial stage, and repeat.