Flat Dumbbell Fly
Chest
Weight & Reps
Dumbbell
The flat dumbbell fly is an isolation exercise that stretches and contracts the chest through a wide arc. It targets the pectoralis major with minimal tricep involvement, focusing on the squeeze at the top.
How to Do Flat Dumbbell Fly
- Maintain a slight bend in your elbows throughout — think of hugging a large tree
- Lower the dumbbells in a wide arc until you feel a deep stretch across your chest
- Squeeze your chest to bring the dumbbells together at the top, not your arms
- Keep your shoulder blades retracted and pinched together on the bench
Form Cues
- Maintain a slight bend in your elbows throughout — think of hugging a large tree
- Lower the dumbbells in a wide arc until you feel a deep stretch across your chest
- Squeeze your chest to bring the dumbbells together at the top, not your arms
- Keep your shoulder blades retracted and pinched together on the bench
Common Mistakes to Avoid
- Bending the elbows too much and turning the fly into a press
- Going too heavy and losing the stretch — flys are a stretch-and-squeeze exercise, not a strength exercise
- Letting the dumbbells touch and clank at the top, which releases tension from the chest
Muscles Worked
Primary
Pectoralis Major (Sternal)
Pectoralis Major (Clavicular)
Secondary
Anterior Deltoid
Biceps Brachii (Short Head)
Recommended Sets and Reps
Strength
4-5 sets
3-5 reps
3-5 min rest
Hypertrophy
3-4 sets
8-12 reps
60-90s rest
Endurance
2-3 sets
15-20 reps
30-60s rest
Variations and Alternatives
Frequently Asked Questions
What muscles does the dumbbell fly work?
The dumbbell fly primarily targets the pectoralis major through a stretch-and-squeeze motion, with minimal tricep involvement. The anterior deltoid and biceps short head assist as stabilizers.
How much should a beginner dumbbell fly?
Beginners should start with 10-20 lb (4.5-9 kg) dumbbells per hand. Flys are an isolation movement — use about 30-40% of your dumbbell bench press weight and focus on the stretch.
Dumbbell fly vs cable crossover — which is better?
Cable crossovers maintain constant tension throughout the range of motion, while dumbbell flys provide a deeper stretch at the bottom. Cables are better for peak contraction, and dumbbells are better for the stretch component.
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