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  7. Dumbbell Bent Over Alternate Rear Delt Fly

Exercise guide

Dumbbell Bent Over Alternate Rear Delt Fly

  • Intermediate
  • Compound
  • Rep-based
  • Back
  • Shoulders
  • Upper legs

This isolation exercise targets the posterior deltoids and upper back muscles to improve shoulder health and posture. Alternating sides increases the demand on your core to stabilize the torso against rotational forces while allowing for greater focus on each individual muscle.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Dumbbell Bent Over Alternate Rear Delt Fly demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Deltoids
  • Rhomboids

Secondary

  • Erector spinae
  • Glutes
  • Hamstrings

Equipment

  • Dumbbell

Setup

  1. Stand with feet shoulder-width apart, holding a dumbbell in each hand with a neutral grip (palms facing each other).
  2. Hinge at the hips until your torso is nearly parallel to the floor, keeping your back flat and core engaged.
  3. Let the dumbbells hang directly beneath your shoulders with a slight bend in your elbows and your knees slightly flexed.

How to do it

  1. Exhale as you lift one dumbbell out to the side in a wide arc, keeping the elbow slightly bent and leading the movement with your elbow.
  2. Raise the weight until your arm is roughly parallel to the floor, focusing on the squeeze in your rear deltoid and shoulder blade.
  3. Inhale as you lower the weight back to the starting position with a controlled 2-second tempo.
  4. Repeat the movement immediately with the opposite arm, alternating sides for the duration of the set.

Form checklist

  • Keep your spine neutral and avoid rounding your lower back or neck.
  • Maintain a consistent slight bend in the elbows; do not allow the movement to turn into a row.
  • Minimize torso rotation and momentum; the only thing moving should be your arm.
  • Keep your weight centered over the middle of your feet to maintain balance.

Pro tips

  • Imagine trying to touch the side walls with your dumbbells rather than just lifting them up to maximize rear delt tension.
  • Rotate your wrists slightly so your pinky fingers are higher than your thumbs at the top of the movement to better isolate the posterior deltoid.
  • Focus on pulling the weight 'out' rather than 'up' to reduce trap involvement.

Make it harder

  • Add a 2-second isometric hold at the peak of each repetition to maximize time under tension.
  • Slow the eccentric (lowering) phase to 3-4 seconds to increase muscle fiber recruitment.

Frequently asked

What muscles does the dumbbell bent over alternate rear delt fly work?
The dumbbell bent over alternate rear delt fly primarily targets the deltoids and rhomboids, and also works the erector spinae, glutes, and hamstrings as secondary muscles.
What equipment do you need for the dumbbell bent over alternate rear delt fly?
The dumbbell bent over alternate rear delt fly uses dumbbell.
Is the dumbbell bent over alternate rear delt fly good for beginners?
The dumbbell bent over alternate rear delt fly is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Band Bent Over Rear Deltoid KickbackIntermediate · deltoids and rhomboids
  • Cable Rear Delt Row Parallel BarIntermediate · deltoids and rhomboids
  • Alternate Front Kick In Place With Arm CirclesBeginner · abs, calves, deltoids, and pectorals
  • Barbell Behind The Back Push PressAdvanced · deltoids, glutes, and quadriceps

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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