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Dumbbell Chest Fly

With arms nearly straight you open the dumbbells in a wide arc from above the chest until a stretch appears across the pecs, then draw them back together along the same curve. The fly isolates the chest and slots best after your pressing work is done. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.

Muscles worked

Chest · pectoralis major Front shoulders · anterior deltoid Serratus anterior

Sets & reps by goal

Goal	Sets × Reps	Rest
Strength	3 sets × 6-8 reps (flys reward moderate loads over maximal ones)	90 sec - 2 min
Muscle	3-4 sets × 9-12 reps	60-90 sec
Endurance	2 sets × 15-20 reps	45 sec

Rep ranges per Helms 2014 · Schoenfeld 2016.

Level — Beginner

Beginner movement, unforgiving loading — light weight and a frozen elbow angle are the whole skill.

Proper form — 5 cues

Fix a soft bend in the elbows and freeze that angle — it never changes mid-rep.
Turn the palms to face each other and keep them facing in all the way.
Lower the arc only until you feel a clear stretch across the chest, never until the shoulders complain.
Draw the weights together as though wrapping your arms around a wide barrel.
Choose a dumbbell noticeably lighter than your pressing weight — the long lever multiplies every kilo.

Breathing: Inhale as the arms open through the arc, exhale as you draw the dumbbells back together.

The 3 mistakes Maddy corrects most

Bending the elbows more as the set gets hard. Shortening the lever quietly converts the fly into a weak press and deletes the stretch the exercise exists for. Fix: Drop to a lighter pair and guard the elbow angle like a rep standard.

Chasing maximum depth on every rep. The bottom of a fly places the shoulder under load in its most vulnerable position, and gravity punishes overreach there. Fix: Stop at the first strong chest stretch and build range gradually over weeks.

Slamming the dumbbells together at the top. Tension drops to nearly zero once the weights stack vertically, so the crash marks the least useful part of the arc. Fix: Finish with the dumbbells apart at ten-and-two and squeeze the pecs for a count.

Common questions

Do I need flys if I already bench press?

Need is strong — pressing builds most of your chest size. Flys add two things presses cannot: a loaded stretch at long muscle length without the triceps limiting the set, and an adduction squeeze across the midline. If chest development lags your pressing strength, a fly variation is usually the first accessory worth adding.

Flat bench, incline or floor — where should I do flys?

A flat bench is the standard and suits most trainees. An incline shifts emphasis toward the upper chest fibres. The floor version caps the stretch where the upper arms meet the ground, which makes it the safest room to learn the arc — a genuinely useful stepping stone before the deeper bench versions.

Why do my shoulders hurt during flys and not presses?

The stretched bottom position of a fly asks the front of the shoulder to stabilise a long lever under load — a demand pressing never quite makes. Reduce depth so the stretch lands in the chest, check that the palms stay facing each other, and lighten the load. If pain persists at any depth, swap the movement and get assessed.

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Dumbbell Bench PressChest Ground Dumbbell Chest PressChest Seated Cable FlyChest Seated Chest Press Hammer GripChest Seated Chest Press Straight GripChest

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