Position yourself prone on an incline bench set to a 45-to-60-degree angle holding a pair of light dumbbells in your hands at arm's length. With your palms facing each other and a slight bend in your elbows, pinch your shoulder blades together as you work the weights up in a wide , arching motion, pausing when your arms are parallel to the ground. Pause for a second, then lower them back down to the starting position. Keeping your palms facing each other will emphasize the entire upper back, while doing the exercise with your thumbs facing each other and pinky side of your hand rising upward will target the rear shoulders a bit more. Finally, rotating your palms outward so your thumb side of your hand lead the movement will bring the external rotators more into play.