Dumbbell Rear Fly exercise animation (Male)

Dumbbell Rear Fly

Target muscle
Deltoid Posterior
Synergist muscles
Deltoid Lateral, Infraspinatus, Teres Minor, Trapezius Lower Fibers, Trapezius Middle Fibers
Equipment
Dumbbell
Body part
Shoulders
Type
Strength

The dumbbell rear fly is a bent-over isolation exercise that targets the rear delts (posterior deltoid), with help from the lateral deltoid, the rotator-cuff muscles (infraspinatus and teres minor), and the mid and lower traps. It builds the back of the shoulders, improves posture, and balances out heavy pressing work.

How to do the Dumbbell Rear Fly

  1. 1Hold a dumbbell in each hand with a neutral grip (palms facing each other) and stand with your feet about hip-width apart, knees slightly bent.
  2. 2Hinge forward at the hips until your torso is close to parallel with the floor, keeping your back flat and your core braced.
  3. 3Let the dumbbells hang straight down beneath your shoulders with a slight, fixed bend in your elbows.
  4. 4Lead with your elbows and raise the dumbbells out to the sides in a wide arc, squeezing your shoulder blades together.
  5. 5Lift until your upper arms reach roughly shoulder height, keeping the weights in line with your torso rather than swinging them up toward your head.
  6. 6Pause briefly at the top with your rear delts fully contracted.
  7. 7Lower the dumbbells under control back to the start, resisting the weight all the way down.
  8. 8Complete your reps, then stand up tall and set the dumbbells down safely.

Form tips

  • Keep a slight, fixed bend in your elbows for the whole set so the rear delts do the work instead of the triceps.
  • Think about pulling with your elbows, not your hands, to keep tension on the back of the shoulders.
  • Use a lighter weight than you expect — this is a small-muscle isolation move, and momentum easily takes over.
  • Keep your neck in a neutral position by looking at a spot on the floor a few feet ahead, not straight down or up.

Common mistakes

  • Using too much weight and swinging the torso to heave the dumbbells up, which shifts the work off the rear delts onto momentum and the lower back.
  • Shrugging the shoulders toward the ears, which recruits the upper traps and takes tension away from the posterior delts.
  • Rounding the lower back when hinging, which puts the spine at risk under load.
  • Bending and straightening the elbows like a row, which turns the fly into an arm movement instead of a rear-delt raise.

Frequently asked questions

What muscles does the dumbbell rear fly work?

It primarily works the rear delts (posterior deltoid), with the lateral deltoid, the infraspinatus and teres minor of the rotator cuff, and the mid and lower traps assisting.

How heavy should I go on rear flies?

Go lighter than you think. The rear delts are small, and using too much weight forces you to swing. Pick a load you can control for 12–20 clean reps with a brief squeeze at the top.

Is the dumbbell rear fly good for beginners?

Yes. It is a simple isolation move that strengthens the often-neglected back of the shoulders and improves posture. Start light and focus on the hip hinge and a flat back before adding weight.

Where should I feel the dumbbell rear fly?

You should feel it in the back of your shoulders (rear delts) and between your shoulder blades. If you mostly feel it in your upper traps or lower back, lighten the load and stop shrugging or swinging.

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