Exercise guide
Dumbbell Alternative Fly
- Intermediate
- Compound
- Rep-based
- Chest
The alternating dumbbell fly isolates the pectorals and anterior deltoids while challenging core stability by moving one arm at a time. This unilateral approach allows for a greater mind-muscle connection and ensures balanced development across both sides of the chest.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Lie flat on a bench with your feet planted firmly on the floor for stability.
- Hold a dumbbell in each hand directly above your chest with palms facing each other (neutral grip).
- Retract your shoulder blades into the bench and maintain a slight, fixed bend in your elbows.
- Position the dumbbells so they are nearly touching at the starting point.
How to do it
- Inhale and slowly lower one dumbbell in a wide arc out to the side until your arm is parallel to the floor, keeping the other arm perfectly still at the top.
- Pause briefly at the bottom of the movement to feel a deep stretch in the pectoral muscle.
- Exhale and use your chest to pull the dumbbell back to the starting position in the same wide arc.
- Repeat the movement with the opposite arm, alternating sides for the desired number of repetitions.
Form checklist
- Keep the stationary arm locked in the vertical position to maintain constant tension.
- Maintain a consistent bend in the elbows throughout the entire range of motion; do not turn the movement into a press.
- Ensure your lower back does not excessively arch off the bench as you lower the weight.
- Control the tempo, especially on the eccentric (lowering) phase, to protect the shoulder joint.
Pro tips
- Imagine you are hugging a large tree to maintain the correct arc and maximize pectoral recruitment.
- Focus on driving your inner elbow toward the midline of your body during the ascent to enhance the peak contraction.
- Squeeze your glutes and core to prevent your torso from rotating toward the moving arm.
Make it harder
- Incorporate a 3-second isometric hold at the bottom of each rep to eliminate momentum and increase time under tension.
- Perform the exercise on an incline bench to shift the focus toward the clavicular head of the pectoralis major.
Frequently asked
- What muscles does the dumbbell alternative fly work?
- The dumbbell alternative fly primarily targets the pectorals, and also works the abs and serratus anterior as secondary muscles.
- What equipment do you need for the dumbbell alternative fly?
- The dumbbell alternative fly uses dumbbell.
- Is the dumbbell alternative fly good for beginners?
- The dumbbell alternative fly is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.