A rear delt fly done with dumbbells strengthens your upper back muscles and shoulders while working on stabilization strength in your spine, deep abdominals and hips. The exercise requires you to maintain a neutral spine position and avoid moving the torso. Doing a rear delt fly with dumbbells requires you to maintain your posture throughout the movement. Use a lighter weight if you find it difficult to perform the exercise with proper form or use a heavier weight if you can do the exercise with little effort, according to the National Academy of Sports Medicine.
Standing Dumbbell Rear Fly
Stand with your legs about hip-width apart and hold a dumbbell in each hand by your side. Choose a weight that allows you to perform eight to 12 repetitions.
Bend your torso forward and bend your legs slightly so that your arms extend below your body with your hands facing each other as you hold the dumbbells. This is the starting position.
Exhale and raise your arms out to your sides with your hands facing down, squeezing your shoulder blades together during the movement. Do not round your spine or move your head forward.
Inhale and lower your arms to the starting position. This completes one repetition. Perform two to three sets of eight to 12 reps.
Single Arm Dumbbell Rear Fly
Stand with your legs about hip-width apart and hold a dumbbell in your left hand by your side.
Bend your torso forward at your waist so that your arms extend below your body. This is the starting position.
Exhale and raise the weight with your left arm, keeping your hand facing down and your right hand on your right thigh. Do not move your torso as you lift. Shift your weight toward your right foot as you lift.
Lower your arm to the starting position as you shift your weight back toward the center of your body. This completes one repetition. Perform two to three sets of eight to 12 reps.
Switch the dumbbell to your right hand and repeat the movement to work this arm. When raising the weight with your right arm, shift your weight toward your left foot. Perform two to three sets of eight to 12 reps.
Stop performing this exercise if you experience pain in any joint, especially if you lack stabilization strength and exhibit excessive curvature in your upper spine. Work on improving your posture and movement patterns before attempting this exercise.