Prone Bench Single Arm Dumbbell Rear Delt Fly
In SetGrip: Dumbbell Rear Delt Fly (Prone Bench, Single Arm)
- Secondary muscles
- Traps, Rhomboids
- Body part
- Shoulders
- Position
- Lying
- Laterality
- Unilateral (one arm at a time)
- Category
- Strength
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Working one dumbbell at a time from a face-down position on the bench combines chest support with a unilateral focus, so each rear delt gets its own strict set. Unlike the across-bench single arm version, you lie along the bench here, which frees the working arm to sweep straight out to the side.
How to do the Prone Bench Single Arm Dumbbell Rear Delt Fly
- Lie face down on a flat bench with a dumbbell in one hand, hanging towards the floor.
- Keep your arm straight and lift the dumbbell out to the side, away from your body.
- Pause for a moment at the top, then slowly lower the dumbbell back down to the starting position.
- Repeat for the desired number of repetitions, then switch to the other arm.
Tip: Lead with the elbows and think of reaching wide rather than lifting up.
Muscles worked
Primary
Delts · Shoulders
Front raises hit the front delt, lateral raises the side, and Y or rear raises the back head; whichever you pick, the burn should build across the top of the shoulder by the last few reps.
Secondary
- Traps — The upper traps will take over if you shrug, so a slight downward pull of the shoulders keeps them out of it.
- Rhomboids
Common mistakes
- Swinging from the hips — a small bounce at the bottom is the sign of a weight that is too heavy; lighten it and lift from a dead stop.
- Shrugging as you raise — the traps take over when the shoulders rise toward the ears; keep them down and lead with the elbows.
- Raising far above shoulder height — on lateral and front raises the upper traps take over past parallel, so stop around shoulder level unless the variation is built to go overhead.
- Locked elbows — keep a soft bend in the elbow throughout so the load stays on the shoulder rather than the joint.
Sets, reps and where it fits
| Goal | Sets × reps | Rest |
|---|---|---|
| Muscle growth | 3–4 × 10–15 per side | 60–90 s |
| Endurance / finisher | 2–3 × 15–20 per side | 45 s |
| Strength | Not ideal — pick a compound lift for the same muscle | — |
Raises are accessory work and belong after the presses in a shoulder or push session. Superset lateral raises with a rear delt fly using the same dumbbells for a complete shoulder finisher.
Variations and alternatives
Similar exercises
Frequently asked questions
What muscles does the Prone Bench Single Arm Dumbbell Rear Delt Fly work?
The Prone Bench Single Arm Dumbbell Rear Delt Fly primarily works the delts. It also involves the traps and rhomboids, which assist the movement and stabilise the joints.
Is the Prone Bench Single Arm Dumbbell Rear Delt Fly good for beginners?
It is rated intermediate, so it suits people who already train regularly. Beginners can still do the Prone Bench Single Arm Dumbbell Rear Delt Fly with light load and a spotter or coach watching the first few sessions; if it feels awkward, pick an easier variation from the alternatives below first.
What can I do instead of the Prone Bench Single Arm Dumbbell Rear Delt Fly?
If you cannot do the Prone Bench Single Arm Dumbbell Rear Delt Fly, try the Behind Back Barbell Rear Delt Raise, the Seated Cable Rear Delt Fly or the Prone Bench Dumbbell Rear Delt Fly. Each of them trains the delts through a similar movement, so you can swap them in without changing the rest of the workout.
How many sets and reps should I do?
It depends on your goal. For the Prone Bench Single Arm Dumbbell Rear Delt Fly, a sensible starting point is muscle growth: 3–4 × 10–15 per side with 60–90 s rest; endurance / finisher: 2–3 × 15–20 per side with 45 s rest. Do it after your compound lifts. It is a finishing movement, not the main event.
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