Dumbbell Fly Form

Prop up your phone and RepSensei counts your dumbbell chest fly reps and flags some visible issues, right on your device. Video never leaves your phone.

How to do it

1. Lie on a flat bench with a dumbbell in each hand, feet flat on the floor and shoulder blades squeezed together.
2. Press the dumbbells up over your chest, palms facing each other, with a slight bend in your elbows.
3. Keeping that bend fixed, open your arms out wide in an arc, as if hugging a big tree.
4. Lower until you feel a stretch across your chest, with your elbows around bench height.
5. Squeeze your chest to bring the dumbbells back up along the same arc until they nearly touch.

Coaching cues

Fixed elbow bend

The elbows stay slightly bent the whole time. If they bend more, it becomes a press.

Hug a tree

Thinking of a wide arc keeps the effort on the chest.

Stop at the stretch

Lower to a stretch in the chest, not to the floor.

Common mistakes and how to fix them

Going too heavy

Heavy flyes force you to bend the elbows and press, or strain the shoulders at the bottom. Fix: Use roughly half the weight you would press, or less, and control the lowering.

Lowering too deep

Dropping the elbows well below the bench over-stretches the front of the shoulder. Fix: Stop with elbows about level with the bench.

Arms locked straight

Straight elbows load the elbow joint and make the lever even longer. Fix: Keep a soft, steady bend in the elbows.

Losing the shoulder blade squeeze

Shoulders roll forward and take over from the chest. Fix: Set the shoulder blades back and down before each set.

Clanking the dumbbells together

Banging them at the top loses tension on the chest. Fix: Stop just before they touch and squeeze.

Muscles worked

Main: Chest. Also: Shoulders, Biceps.

Who should take care

If you have had shoulder problems, start with a cable or machine fly where the range is easier to control. Stop if you feel pain in the front of the shoulder and see a physiotherapist.

Variations

• Butterfly: Easier: the pec deck machine guides the arc.
• Flat Bench Cable Flyes: Alternative: constant tension from cables.
• Incline Dumbbell Flyes: Variation: an incline bench for more upper chest.
• Dumbbell Bench Press: Alternative: a press that lets you lift heavier.

Filming your dumbbell chest fly

Prop the phone at bench height, side-on or slightly behind your head, two metres away, so your elbows are visible at the bottom. You can track it with the RepSensei camera, which counts reps and can flag some visible issues from one angle; it cannot see everything. See how to film your form.

Questions

How heavy should dumbbell flyes be?

Much lighter than a press. Choose a weight you can lower under control for 10 to 15 reps.

Are flyes or presses better for the chest?

Presses let you lift heavier; flyes add a big stretch. Most programmes use presses first and flyes as an extra.

How low should I go?

Until you feel a stretch across your chest, typically with elbows around bench height.

See the Dumbbell Flyes exercise guide with a 3D figure.

More form guides

• Bench Press form
• Push-Up form

General guidance, not medical advice. Stop if anything hurts. The camera can miss things, so no issue seen doesn't mean perfect form.