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  7. Dumbbell One Arm Reverse Fly With Support

Exercise guide

Dumbbell One Arm Reverse Fly With Support

  • Intermediate
  • Isolation
  • Rep-based
  • Back
  • Shoulders

This unilateral isolation exercise targets the posterior deltoids and mid-back muscles while using a bench for stability to eliminate momentum and isolate the target muscles. It is highly effective for correcting muscle imbalances and improving shoulder health and posture.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Dumbbell One Arm Reverse Fly With Support demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Deltoids
  • Rhomboids
  • Trapezius

Secondary

  • Biceps
  • Serratus anterior

Equipment

  • Dumbbell

Setup

  1. Set an incline bench to a 45-degree angle.
  2. Stand or kneel behind the bench, leaning your non-working forearm and forehead against the top of the backrest for total body stability.
  3. Hold a dumbbell in your working hand with a neutral grip (palm facing your body), letting the arm hang straight down toward the floor.
  4. Position your feet in a staggered stance to ensure a stable base and keep your spine neutral.

How to do it

  1. Exhale as you raise the dumbbell out to the side in a wide arc until your arm is roughly parallel to the floor.
  2. Lead the movement with your elbow, keeping a slight, fixed bend in the joint throughout the lift.
  3. Inhale as you slowly lower the dumbbell back to the starting position, maintaining tension on the rear delt.
  4. Follow a controlled tempo, such as 2 seconds up and 2 seconds down, avoiding any bouncing at the bottom.

Form checklist

  • Keep your torso and hips square to the bench; do not rotate your body to help lift the weight.
  • Maintain a slight bend in the elbow to protect the joint and focus tension on the deltoid.
  • Avoid shrugging the weight toward your ear; keep the shoulder blade depressed.
  • Ensure the movement occurs at the shoulder joint only, not by swinging the torso.

Pro tips

  • Think about pushing the dumbbell 'out' toward the side wall rather than 'up' to better engage the posterior deltoid.
  • Slightly rotate your wrist so your pinky is higher than your thumb at the top of the movement to maximize rear delt recruitment.
  • Pause for a one-second squeeze at the peak of the contraction to fully engage the rhomboids and traps.

Make it harder

  • Implement a 3-second isometric hold at the top of each repetition.
  • Slow down the eccentric (lowering) phase to 4 seconds to increase time under tension.

Frequently asked

What muscles does the dumbbell one arm reverse fly with support work?
The dumbbell one arm reverse fly with support primarily targets the deltoids, rhomboids, and trapezius, and also works the biceps and serratus anterior as secondary muscles.
What equipment do you need for the dumbbell one arm reverse fly with support?
The dumbbell one arm reverse fly with support uses dumbbell.
Is the dumbbell one arm reverse fly with support good for beginners?
The dumbbell one arm reverse fly with support is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Band Incline Y RaiseIntermediate · deltoids, rhomboids, and trapezius
  • Dumbbell Incline Rear Lateral RaiseIntermediate · deltoids, rhomboids, and trapezius
  • Dumbbell Rear FlyBeginner · deltoids, rhomboids, and trapezius
  • Dumbbell Rear Lateral RaiseIntermediate · deltoids, rhomboids, and trapezius

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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