Dumbbell Fly
The dumbbell fly is a chest isolation exercise: lying on a flat bench, you open two dumbbells out to the sides in a wide arc and bring them back together over your chest with a fixed elbow bend. It works the chest (mainly the mid-chest fibres) with little help from the triceps, and loads the chest most at the stretched bottom of the arc.
Also called: DB Fly, Flat Fly, Chest Fly, Dumbbell Chest Fly · Equipment: dumbbell · Pattern: push
Step by step
- Sit on the end of a flat bench with a dumbbell resting on each thigh. Lie back and bring the dumbbells up over your chest, arms nearly straight and palms facing each other.
- Plant your feet flat on the floor. Pull your shoulder blades back and down into the bench and keep them there for the whole set.
- Set a slight bend in your elbows, about 15–20°, and keep that angle fixed for every rep.
- Breathe in and open your arms out to the sides in a wide arc, under control, until you feel a moderate stretch across your chest with your upper arms about level with your torso.
- Breathe out and bring the dumbbells back up along the same arc, as if hugging a large barrel, until they meet over your chest just short of touching.
- Keep your wrists straight and your elbows pointing out to the sides throughout, so the movement comes from the shoulders.
- After the last rep, bend your elbows, bring the dumbbells to your chest and sit up with them resting on your thighs.
- Hug a big barrel
- Open to a stretch, upper arms level with your torso
- Shoulder blades back and down into the bench
- Elbow bend set once and fixed
- Control the dumbbells out
- Squeeze them together, just short of touching
In VALDA, these cues are one tap away on the exercise while you train.
What it trains
| Muscle | Role | Evidence |
|---|---|---|
| Pectoralis major: sternocostal (mid) | Prime mover | C |
| Pectoralis major: clavicular (upper) | Secondary | C |
| Pectoralis major: abdominal (lower) | Secondary | C |
| Anterior deltoid: anterior | Secondary | C |
| Biceps brachii: short head | Stabiliser | D |
| Pectoralis minor | Stabiliser | D |
| Serratus anterior | Stabiliser | D |
Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.
What goes wrong, and the fix
Taking the dumbbells too deep
Fix: Open only until your upper arms are about level with your torso.
Elbows bending and straightening
Fix: Set a 15–20° elbow bend at the start and hold that angle for every rep.
A load too heavy to hold the arc
Fix: Pick a load you can move through the full wide arc with a fixed elbow angle.
Shoulder blades coming off the bench
Fix: Pull your shoulder blades back and down before the first rep and hold them there.
Clanking the dumbbells together at the top
Fix: Bring the dumbbells together over your chest, just short of touching.
Dropping into the stretch
Fix: Open your arms at a steady pace and pause briefly at the stretch.
What the research says
Muscle growthGeneral fitnessEndurance
- Role next to pressing — An EMG study at matched effort found the barbell bench press produced more chest, shoulder and triceps activity than the dumbbell fly. The fly isolates the chest rather than out-working the press, so it is usually programmed after pressing.
- Load and effort — Research comparing loads finds muscle growth is similar across a wide range of loads when sets finish close to failure, and sets that end a few reps short of failure capture most of the benefit. Because the stretched bottom limits how heavy a fly can go, moderate loads for about 8 to 15 reps are the common choice.
- The stretch — Studies on the thigh and elbow flexors found training at longer muscle lengths produced as much or more growth than shorter ranges. For the chest this is plausible but untested, and there is no direct research on fly depth.
- Volume — Research links more weekly sets for a muscle to more growth, with diminishing returns. Presses also train the chest, and counting them as partial sets improves how well weekly volume predicts growth.
- Pairing with a row — An acute trial found alternating a muscle with its opposite completed more work in less time without a loss of performance in each set, which is why flies are often paired with rows.
Swap it mid-workout
With VALDA Pro, FLEX offers alternatives like these when you swap an exercise mid-workout.
Log the dumbbell fly in VALDA, with these cues one tap away while you train and your history for it in one place.
General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.