Rear Delt Flyes
The dumbbell rear delt fly is an isolation exercise where you hinge forward and raise light weights out to your sides. It builds the posterior delts, the muscles at the back of your shoulders, which often get less work than the fronts. It suits beginners and experienced lifters alike, as long as you are happy to go light and focus on control.
Muscles worked
The Rear Delt Flyes mainly works your posterior delts, with your traps and lats helping.
Setting up
- Choose light dumbbells, 2-6 kg each for most beginners. This move is about feeling the back of the shoulders work, not lifting heavy.
- Stand with your feet about hip-width apart and a soft bend in your knees. Hinge forward at the hips until your torso is roughly 45 degrees or lower, keeping your back flat and your head in line with your spine.
- Let the dumbbells hang straight down beneath your shoulders, palms facing each other, with a slight bend in your elbows that stays fixed throughout.
- Look at the floor a short distance ahead of your feet so your neck stays long and relaxed.
How to do the Rear Delt Flyes
- Brace your midsection and set your shoulder blades gently down and back, before you start to lift.
- Start the movement by leading with your elbows, moving the dumbbells out and slightly back in a wide arc rather than lifting with your hands.
- Raise the weights until your upper arms are roughly level with your torso, or just above, with your elbows slightly higher than your wrists.
- Pause for a second at the top and squeeze your shoulder blades together, feeling the work across the back of your shoulders.
- Lower the dumbbells slowly over about two to three seconds, keeping the same arc and the same elbow bend.
- Stop just short of letting the weights touch or rest, then start the next rep with your torso still in the same position.
Form tips
- Think of pushing your elbows out to the walls beside you, not lifting the dumbbells up. This keeps the work on the rear delts.
- Keep your shoulders away from your ears. If you feel the tops of your shoulders and neck taking over, your traps are doing too much, so lower the weight.
- Hold your torso still. If your chest rises as the weights go up, you are swinging, so go lighter and slow down.
- Imagine holding a pencil between your shoulder blades at the top of each rep, so you finish with a clear squeeze.
- If balancing bent over is tricky, rest your chest on an incline bench set to about 30-45 degrees, or sit on the end of a bench and lean forward.
Common mistakes
Swinging the weights up with momentum
Drop to a lighter pair of dumbbells and take two to three seconds to lower each rep. Your torso angle should not change at all during the set.
Shrugging the weights up
Keep your shoulders down and away from your ears, and lead with your elbows. If you can only manage this with lighter dumbbells, use them.
Standing too upright
Hinge further forward at the hips until the dumbbells hang under your shoulders. If you stand tall, the movement turns into a side raise and the rear delts do less.
Straightening and bending the elbows during the rep
Set a slight bend at the start and hold that angle all the way up and down. Locked-straight arms or bending and pulling like a row shifts the work away from the target muscles.
Sets and reps
| Build strength | 3-4 sets of 8-10 reps with a weight that lets you keep strict form, resting 90-120 seconds. Add weight in small steps only when every rep looks the same as your first. |
|---|---|
| Build muscle | 3-4 sets of 12-15 reps, resting 60-90 seconds. Stop each set when your form starts to slip, about 1-2 reps before you would need to swing. |
| Fat loss and general fitness | 2-3 sets of 12-15 reps, resting 45-60 seconds, as part of a full-body workout. This is a small isolation exercise, so pair it with bigger compound lifts and regular activity. |
Pick a weight where the last rep or two of each set is hard but your form stays clean. When every set feels easy, it's time to go up.
Rear Delt Flyes alternatives
Machine taken, or want some variety? These work the same main muscles.
Rear Delt Flyes FAQs
What weight should I use for rear delt flyes?
Start lighter than you think, often 2-5 kg per hand. You should be able to pause at the top and lower under control. If you have to swing or shrug to finish a rep, the weight is too heavy.
Why do I feel rear delt flyes in my traps or upper back instead of my shoulders?
This usually means the weights are too heavy or your shoulders are creeping up towards your ears. Lower the weight, keep your shoulders down and lead with your elbows. Some work in the traps and lats is normal, but you should feel the back of your shoulders most.
Can I do rear delt flyes seated or on an incline bench?
Yes. Sitting on the end of a bench and leaning forward, or lying chest-down on an incline bench, takes away the need to hold your hinge. That makes it easier to keep your torso still and focus on the rear delts, and it is a good option for beginners.
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