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Chest exercises

Dumbbell fly

Also called dumbbell chest fly, flat dumbbell fly, dumbbell flye, dumbbell flies.

What is a dumbbell fly?

A dumbbell fly is a chest isolation exercise performed lying on a flat bench. You hold a dumbbell in each hand, open your arms out to the sides and bring them back above your chest while keeping a small, nearly fixed bend in the elbows. It mainly trains the pectoralis major, with the front of the shoulders assisting. Unlike a dumbbell press, the elbows do not bend and straighten through the repetition.

Two-frame anatomical illustration of a flat-bench dumbbell fly on a white background. In the left frame, a man lies on a flat bench with his feet on the floor and holds a dumbbell in each hand. His arms are open wide at chest level with a small bend in both elbows and his palms facing inward. In the right frame, the same man has brought the dumbbells together above his chest while keeping the slight elbow bend. The pectoralis major is shaded bright red in both frames. Lighter shading also appears over the front of the shoulders, biceps and parts of the forearms.

How do you perform a dumbbell fly?

Set up

  1. Set a bench flat, sit at the end and rest one dumbbell on each thigh.
  2. Use your thighs to guide the dumbbells up as you lie back, then hold them above your chest with your palms facing each other.
  3. Plant your feet, draw your shoulder blades back against the bench and soften your elbows slightly.

Execution

  1. Open your arms out to the sides in a wide arc, keeping the same small bend in your elbows.
  2. Stop when your upper arms reach about the line of your torso, or sooner if you cannot keep your shoulders comfortable and controlled.
  3. Bring the dumbbells back above your chest along the same arc without turning the movement into a press.
  4. After the final rep, bring the dumbbells toward your chest, raise your knees to meet them and use your thighs to help you sit up.

Common mistakes

  • Bending and straightening the elbows

    Changing the elbow angle turns the return into a press and makes the path harder to repeat. Choose lighter dumbbells if the arms cannot hold the same slight bend.

  • Lowering past a controllable range

    The long arm position makes the bottom the hardest part to stop. End the descent while the shoulders still feel comfortable and the dumbbells can reverse smoothly.

  • Letting the shoulders roll forward

    That changes the stable position you set on the bench. Keep the shoulder blades against the pad while the arms move around them.

  • Using dumbbells that turn the arc into a press

    If the elbows keep bending as the weights descend, the load is too much for a repeatable fly. Reduce it until the elbow angle can stay nearly fixed.

  • Dropping the dumbbells out to the sides after the set

    The arms are least supported in that position. Bring the weights inward first and use the thighs to help you return to sitting.

Where it fits in a session

After the main pressing work in a chest or upper-body session, when a lighter isolation movement fits the plan.

Use a load that lets the elbows keep the same slight bend and the bottom position stay controlled. If either changes from rep to rep, reduce the weight or shorten the range.

Muscles worked

Front
Front — Schematic surface view. Some muscles are partly visible or not shown.
Back
Back — Schematic surface view. Some muscles are partly visible or not shown.

Primary

Secondary

Select a muscle name to locate it.

Schematic surface view. Some muscles are partly visible or not shown.

The compact list reflects the overlap across all three required movement-specific checks: each identifies the chest or pectoralis major as the target, and each includes the front of the shoulder. The checks disagreed over whether to include biceps brachii, coracobrachialis or triceps, so those muscles are not listed as targets.

Scientific studies on dumbbell flyes

Direct comparisons with presses have measured muscle activity. They help describe the movement, but do not establish which exercise builds more chest muscle.

Flyes and presses place different demands on the arms. The available comparisons do not establish a muscle-growth winner or an ideal fly depth.

Do flyes work the chest more than presses?

The findings are mixed. In 17 trained men, a six-repetition maximum test found greater average chest, front-shoulder and triceps activity with a barbell press. Biceps activity was greater during flyes, even though the elbow angle stayed nearly fixed.

An earlier study of 12 men and women found no clear chest or front-shoulder activation difference between barbell presses, dumbbell presses and flyes. It tested three repetitions with each exercise’s six-repetition maximum.

These different protocols do not establish equivalent training effects or a growth advantage. A muscle-activity recording is not a measurement of muscle gained.

Sources

Does the comparison change through the repetition?

Yes. In the 17-man study, chest activity favored the press near the top of the lifting phase, but did not clearly differ in the lower or middle portions. The earlier study also found a shorter relative activation time during flyes.

Neither experiment compared training through different fly depths. These results do not establish that a deeper stretch, shortened repetitions or touching the dumbbells together produces more growth.

Sources

Variations

  • Anatomical illustration of an incline dumbbell fly at the open and closed positions, with the chest highlighted.
    Incline dumbbell flyUses an inclined bench while keeping the same wide arm arc and nearly fixed elbow angle.
  • Decline dumbbell fly — Uses a decline bench, changing the body's angle to the weights.
  • Dumbbell floor fly — Uses the floor to stop the upper arms and limit the bottom range.
  • Two frames of a standing cable crossover, side by side. A muscular figure stands in a split stance, one foot forward and flat and the rear heel lifted, torso upright, holding a handle in each hand. The machine itself is not drawn: each cable runs up and away out of the frame, so the two high pulleys are implied rather than shown, and there is no upright or weight stack in the picture. In the left frame the arms are open wide at shoulder height with the cables taut and the elbows slightly bent. In the right frame the arms have swept down and forward along a wide arc so the two handles meet in front of the hips, the elbow bend unchanged. The chest is shaded red in both frames, across the whole of the pectoral muscle rather than an upper or lower portion; the rest of the body is drawn in grey.
    Cable crossoverUses two cable handles while standing instead of dumbbells on a bench.
  • Anatomical illustration of a seated pec deck fly before and after the arm pads move together, with the chest highlighted.
    Machine chest flyUses a chest fly machine whose pads or handles guide the arm path.
  • Single-arm dumbbell fly — Moves one dumbbell at a time while the other arm stays out of the repetition.

Related tools

Frequently asked questions

What muscles do dumbbell flies work?

Dumbbell flies mainly train the pectoralis major, with the anterior deltoid at the front of the shoulder assisting. Some reference lists include additional arm muscles, but they do not agree on those as muscles the exercise trains, so this guide keeps the list compact.

What is the difference between a dumbbell fly and a dumbbell press?

A fly keeps a small, nearly fixed bend in the elbows while the arms open and close in a wide arc. A press bends the elbows as the dumbbells lower and straightens them as the weights rise. The same bench and dumbbells can be used, but the movements are different.

How low should I go on a dumbbell fly?

Lower until your upper arms are around the line of your torso, or stop sooner if you cannot keep the shoulders comfortable and controlled. The picture shows one person's bottom position, not a depth every reader has to copy.

Should my arms be straight during a dumbbell fly?

Keep a small bend in the elbows rather than locking them rigidly. Hold that angle through the repetition so the movement stays an arm arc instead of becoming a press.

Should the dumbbells touch at the top?

No. Bring them above the chest and close together under control. There is no need to knock them together or reach farther by lifting the shoulders away from the bench.

Can I do dumbbell flies without a bench?

A dumbbell floor fly is the closest alternative. The floor stops the upper arms earlier and therefore limits the bottom range, so treat it as a variation rather than trying to recreate the bench setup on unstable furniture.

Are cable crossovers the same as dumbbell flies?

They share the wide chest-fly arm motion, but the setup is different. A cable crossover is performed standing between two pulleys, while this guide covers two dumbbells on a flat bench.

Sources

  1. Baig MA, Bordoni B. Anatomy, Shoulder and Upper Limb, Pectoral Muscles. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK545241/
  2. Elzanie A, Varacallo MA. Anatomy, Shoulder and Upper Limb, Deltoid Muscle. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK537056/
  3. Solstad TE, Andersen V, Shaw M, Hoel EM, Vonheim A, Saeterbakken AH. A Comparison of Muscle Activation between Barbell Bench Press and Dumbbell Flyes in Resistance-Trained Males. 2020. https://www.jssm.org/jssm-19-645.xml-Fulltext
  4. Welsch EA, Bird M, Mayhew JL. Electromyographic activity of the pectoralis major and anterior deltoid muscles during three upper-body lifts. 2005. https://pubmed.ncbi.nlm.nih.gov/15903389/

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