FITBODY Exercise Library · Shoulders
Rear Delt Fly
The rear delt fly, also called the reverse dumbbell flye, strengthens the back of your shoulders and upper back for balanced shoulders and better posture, a move most training programs leave underworked in women over 40.
How to Do the Rear Delt Fly
The rear delt fly, often called the reverse dumbbell flye or the dumbbell rear delt raise, is a cornerstone move for sculpting balanced shoulders. It targets the posterior deltoids, and its benefits go well beyond looks, supporting posture, shoulder stability, and functional strength. Balanced shoulders need work across the front, side, and back of the shoulder, and this is the move that covers the back.
Keep your neck long and in line with your spine, and let the movement come from your shoulders, not a swing of the weights. If you cannot feel your rear delts, adjust your torso angle slightly and drop the weight. With the women I coach, lighter and stricter always wins here.
What Muscles Do Reverse Flyes Work?
Reverse flyes primarily target the posterior deltoids at the back of the shoulders, but the movement engages several supporting muscles that make it a well rounded upper back exercise. For a closer look at the shoulder muscle itself, see this deltoid anatomy overview. Building the back of the shoulder fits naturally into a broader strength training plan for women over 40.
See the full muscle breakdown
- Posterior deltoids: the main target, moving the arm out and back and building balanced shoulders and posture.
- Rhomboids: retract the shoulder blades toward the spine, a core action of the movement.
- Trapezius: the middle and lower fibers assist the scapular retraction and depression.
- Infraspinatus and teres minor: rotator cuff muscles that externally rotate and stabilize the shoulder.
- Erector spinae: stabilize the back through the hinge position.
- Serratus anterior and latissimus dorsi: support scapular stability and keep the trunk steady.
Sets and Reps
The rear delts are small and respond best to lighter load and higher reps done with control. Choose a weight you can pause and squeeze at the top, not one you have to swing.
| Goal | Sets | Reps |
|---|---|---|
| Posture and rear delt focus | 3 | 12 to 15 |
| Muscle building | 3 to 4 | 8 to 12 |
| Beginner or returning | 2 | 12 to 15 |
Rest 45 to 60 seconds between sets. Keep the load light enough to pause and squeeze at the top, and place this after your main pressing or pulling work.
Benefits of the Reverse Flye
- Shoulder strength, stability, and shape. Strengthening the posterior deltoids adds to shoulder stability and creates a more balanced, proportionate upper body.
- Posture correction. Building the back of the shoulders and upper back counteracts the forward slouch and rounded shoulders that come from long hours of sitting.
- Shoulder pain relief. Balancing the forces across the shoulder joint distributes load more evenly and supports long term joint health.
- Athletic performance. Stronger, more stable shoulders support upper body power and help protect against common shoulder injuries.
Variations and Modifications
Seated Reverse Dumbbell Fly
Sit on the end of a bench and hinge forward over your thighs, then run the same fly. Sitting removes lower back fatigue and makes it easier to stay strict through each rep.
Chest Supported Reverse Fly
Lie face down on an incline bench set around thirty to forty five degrees. The bench takes the lower back and momentum out entirely, so the rear delts do all the work.
Cable or Band Reverse Fly
Use a light band or cable for steady tension through the whole range, which many women feel more clearly than dumbbells. It pairs well with a broader strength training plan.
The rear delt fly sits alongside the other moves in my best posture exercises for women, including the scapular retraction exercise, wall angels, and the superman hold. Work them together for a complete upper back and posture routine.
Common Mistakes to Avoid
- Swinging with momentum. Slow down and lead with the elbows so the rear delts do the work, not your lower back.
- Going too heavy. Heavy load pulls the bigger traps and lats in. Lighten up so you can pause and squeeze at the top.
- Shrugging at the top. Keep your shoulders down and away from your ears as you lift.
- Rounding the back. Keep a flat back and a braced core through the hinge to protect your spine.
Are Reverse Flyes Bad for Your Rotator Cuff?
Done with good form and appropriate weight, reverse flyes are generally not bad for the rotator cuff. In fact, they can help strengthen the muscles around it, including the infraspinatus and teres minor, and improve overall shoulder stability and mobility. Like any exercise, though, they carry a risk if done poorly, so a few points keep them safe.
- Proper form. Keep a slight bend in the elbows, avoid lifting the weights above parallel, control the lowering phase, and do not shrug the shoulders toward the ears.
- Appropriate weight. Weights that are too heavy compromise form and strain the cuff. Start light and build gradually.
- Controlled movements. Smooth, controlled reps prevent the strains that jerky, rapid motions can cause.
- Strength and flexibility. Train all parts of the deltoid and the cuff for balance, and keep up shoulder mobility work.
- Listen to your body. Stop if you feel pain beyond normal muscle fatigue, and check with a professional or physical therapist for guidance.
Rear Delt Fly FAQs
What muscles does the reverse dumbbell fly work?
The reverse dumbbell fly primarily works the rear deltoids, the back portion of your shoulder muscles, along with the rhomboids and middle trapezius that pull your shoulder blades together. The rotator cuff assists by stabilizing and rotating the shoulder through the movement. These are the muscles that hold your shoulders back and counter the forward, rounded position that builds up from sitting and pressing exercises. Because most training programs favor the front of the body, the rear delts are often underdeveloped. In my coaching I use the reverse fly to balance the shoulders and support better posture.
Is the reverse dumbbell fly good for posture?
Yes, the reverse dumbbell fly is one of the better exercises for posture, because it directly strengthens the rear delts and upper back that pull your shoulders back. Rounded shoulders come from a combination of a tight, dominant front side and a weak back side, and this movement loads the weak back side. Research on scapular strengthening in women found improvements in forward head and shoulder posture over a few weeks of consistent work. For the best result, I pair the reverse fly with chest and shoulder mobility so both sides of the imbalance are handled. Steady, light, consistent reps do more here than heavy load.
How much weight should I use for reverse dumbbell flyes?
Start much lighter than you would for most exercises, often just three to eight pounds, because the rear delts are small and easily overpowered by bigger muscles. The right weight lets you pause and squeeze at the top without swinging or shrugging. If the dumbbells pull you out of your hinge or your traps take over, the load is too heavy. It is better to earn a clean, controlled rep than to move a heavier weight sloppily. You can add small increments over time as the rear delts get stronger.
How often should I do reverse dumbbell flyes?
Two to three times a week is a good target, since the rear delts recover quickly and respond well to regular work. You can include them on upper body or shoulder days, or add a light set as posture work between other exercises. Two or three sets of twelve to fifteen reps suits most people. Because the load is light, you do not need long recovery between sessions. Consistency across the week matters more than pushing any single set hard.
Why do I feel reverse dumbbell flyes in my traps or neck instead of my rear delts?
Feeling the movement in your traps or neck usually means the weight is too heavy or you are shrugging as you lift, so the bigger upper back muscles take over. The fix is to lighten the load, keep your shoulders pulled down away from your ears, and lead the movement with your elbows rather than your hands. Slowing the tempo and pausing at the top also helps you find the rear delts. It can take a few sessions of light, deliberate practice before the right muscles switch on. If you feel any sharp shoulder or neck pain, stop and check with your physical therapist or doctor.
References
- Campos, Yuri A. C., et al. “Different Shoulder Exercises Affect the Activation of Deltoid Portions in Resistance-Trained Individuals.” Journal of Human Kinetics, vol. 75, no. 1, 2020, pp. 5-14, doi.org/10.2478/hukin-2020-0033.
- Coratella, Giuseppe, et al. “An Electromyographic Analysis of Lateral Raise Variations and Frontal Raise in Competitive Bodybuilders.” International Journal of Environmental Research and Public Health, vol. 17, no. 17, 2020, article 6015, doi.org/10.3390/ijerph17176015.
- Bergquist, Ronny, et al. “Muscle Activity in Upper-Body Single-Joint Resistance Exercises with Elastic Resistance Bands vs. Free Weights.” Journal of Human Kinetics, vol. 61, no. 1, 2018, pp. 5-13, doi.org/10.1515/hukin-2017-0137.
- Valdes-Badilla, Pablo, et al. “Effectiveness of Elastic Band Training and Group-Based Dance on Physical-Functional Performance in Older Women with Sarcopenia: A Pilot Study.” BMC Public Health, vol. 23, 2023, doi.org/10.1186/s12889-023-17014-7.
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I’m Julie Lohre, an IFBB Fitness Pro and certified personal trainer and nutrition specialist. For more than 20 years I have helped women over 40 get stronger, leaner, and more confident through personalized online coaching built around their real lives.