Dumbbell Rear Fly
Reviewed by Dylan Maurick, Physiotherapist
The Dumbbell Rear Fly is an isolation exercise that strengthens the rear shoulders and upper back to improve posture and shoulder balance.
Dumbbell Rear Fly
Muscles Worked: Dumbbell Rear Fly
The dumbbell rear fly mainly trains your rear delts, the part of your shoulders that pulls your upper arms out and back. Your traps and other upper back muscles help keep your shoulder blades steady so the rear delts can do the work. Because the weight is far from your body, even light dumbbells create a lot of tension at the top. You should feel the back of your shoulders and upper back working, not your lower back or neck.
Technique and form
How to perform the Dumbbell Rear Fly
- Stand with feet shoulder-width apart holding a dumbbell in each hand, then hinge at the hips to bring your torso parallel to the floor while maintaining a neutral spine.
- Allow the dumbbells to hang directly beneath your shoulders with palms facing each other and a slight bend in your elbows.
- Brace your core and squeeze your shoulder blades together as you prepare for the movement, maintaining a flat back position.
- Inhale, then exhale as you raise both arms out to the sides, keeping the slight bend in your elbows consistent throughout the movement.
- Continue lifting until your arms are approximately parallel to the floor, forming a T-shape with your torso.
- Focus on using your rear deltoids and rhomboids to control the motion, rather than momentum or arm strength.
- Pause briefly at the top position, squeezing your shoulder blades together before slowly lowering the weights back to the starting position while inhaling.
- Maintain tension in your upper back throughout the entire set, avoiding any swinging or jerking motions.
Important information
- Keep your neck aligned with your spine throughout the exercise, avoiding the tendency to look up or strain forward.
- Choose a weight that allows you to maintain proper form—using too heavy dumbbells will cause you to recruit your trapezius muscles instead of targeting the rear deltoids.
- Make sure your elbows stay slightly bent at the same angle during the entire movement to protect your joints and maximize rear deltoid engagement.
- If you experience shoulder pain during this exercise, try reducing the range of motion or switching to a supported version where your chest rests on an incline bench.
Is the Dumbbell Rear Fly good for muscle growth?
Yes. The dumbbell rear fly is a solid muscle-building exercise for the rear delts because it loads a part of the shoulders that many pressing exercises barely challenge. If your goal is rounder shoulders and better upper-back balance, this move fills a gap that bench presses, overhead presses, and front raises often leave.
- Direct rear-delt tension — The rear fly puts the back of your shoulders in the main role instead of making them assist another lift. That matters because rear delts are often undertrained compared with front delts from pressing work, so direct sets can help bring up lagging shoulder size.
- Light weight works well — You do not need heavy dumbbells here because the long arm position makes the exercise hard fast. That lets you train the target muscle with less joint stress than trying to turn it into a heavy row or shrug.
- Better shoulder balance — Building the rear delts and upper back can help balance out lots of chest and front-shoulder training. Pairing rear flyes with presses or even dumbbell-lateral-raise gives your shoulders more complete development from front to side to back.
- Easy to place in a program — Since this is an isolation lift with a low fatigue cost, it fits well after bigger pulling work or on shoulder day. It also pairs well with cable-standing-face-pull-with-rope if you want extra upper-back and rear-delt volume without beating up your recovery.
Programming for muscle growth
Do 3-4 sets of 10-20 reps with 45-75 seconds rest, 2-3 times per week. Higher reps usually work better here because the rear delts respond well to smooth, controlled reps and lighter loads. Stop each set when your form starts turning into a shrug or swing, because that shifts work away from the rear delts.
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FAQ - Dumbbell Rear Fly
Dumbbell rear flies primarily target the posterior deltoid (rear shoulder) muscles, while also engaging the trapezius, rhomboids, and infraspinatus muscles of the upper back. This comprehensive activation makes it excellent for creating balanced shoulder development and improving posture.
Choose weights that allow you to maintain perfect form while feeling tension in your rear deltoids throughout the movement—typically much lighter than what you'd use for pressing exercises. Most lifters benefit from dumbbells between 5-20 pounds, focusing on controlled movement rather than heavy loading.
The most common mistakes include using momentum to swing the weights, insufficient hip hinge positioning, and internally rotating the shoulders during the movement. Keep your chest parallel to the floor, maintain a slight elbow bend throughout, and focus on squeezing your shoulder blades together at the top of the movement.
Include rear flies 1-3 times weekly, either on shoulder days or back training sessions. Since rear deltoids recover relatively quickly and are often undertrained, you can safely target them more frequently than larger muscle groups, especially if you have rounded shoulders or postural issues.
Try face pulls, bent-over cable flies, or rear deltoid machine flies as alternatives that may feel more comfortable. You can also perform the movement lying face-down on an incline bench, which provides additional support and often reduces stress on the shoulder joint while maintaining muscle activation.
Workouts with Dumbbell Rear Fly
Dumbbell Rear Fly
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