Chest Exercise · Dumbbell

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Dumbbell Decline One Arm Fly

Working one arm at a time on a decline fly forces the core to resist rotation throughout the set, since only one side of the chest is under load at any moment. That unilateral setup also makes it easier to feel exactly where the stretch and contraction happen without a stronger arm compensating. It's a slower, more deliberate way to train the lower chest than doing both arms together.

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Also known as: Db Decline One Arm Fly, Dumbell Decline One Arm Fly

Category

Chest

Equipment

Dumbbell

Target

Pectorals

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Exercise reference published by PlanWorkouts; see our editorial standards.

How to Do the Dumbbell Decline One Arm Fly

1. Lie back on a decline bench holding a dumbbell in one hand, resting it on your thigh.
2. Use your thigh to help raise the dumbbell up to shoulder width, palm facing your torso.
3. Turn your wrist so your palm faces forward.
4. Inhale and slowly lower the dumbbell out to the side until you feel your chest stretch.
5. Exhale and use your chest muscles to raise the dumbbell back to the starting position.
6. Complete the desired number of repetitions, then switch to the other arm.

Technique & Form Tips

Move your arms in a controlled arc toward the front of your body, focusing on horizontal adduction. Follow the demonstrated elbow angle and body support, ensuring your range of motion remains within your personal comfortable limits.

Common Mistakes to Avoid

• Turning fly into a press: Keep the demonstrated elbow bend instead of repeatedly bending and straightening the elbows to press the load.
• Overstretching: Limit the backward movement of your arms to a range that feels stable and comfortable.
• Rushing the contraction: Use a controlled tempo through the entire range, especially as your hands move toward the center.

How to Breathe During This Exercise

Coordinate your breath with the opening and closing phases of the movement.

Comfort and Control

Choose a load and range you can control. Stop if the movement causes pain. If discomfort persists, stop and ask a qualified professional about an appropriate exercise and range.

General guidance: Mayo Clinic on weight-training technique. Follow the specific movement steps above for this variation.

Muscles Worked

The Dumbbell Decline One Arm Fly mainly targets your Pectorals, with your Shoulders helping support the movement.

More Chest Exercises

Archer Push Up Body Weight · Pectorals Assisted Chest Dip (kneeling) Leverage Machine · Pectorals Assisted Seated Pectoralis Major Stretch With Stability Ball Assisted · Pectorals Assisted Wide-Grip Chest Dip (kneeling) Leverage Machine · Pectorals Band Bench Press Band · Pectorals Band One Arm Twisting Chest Press Band · Pectorals

More Pectorals Exercises

Barbell Bench Press Barbell · Pectorals Barbell Decline Bench Press Barbell · Pectorals Barbell Decline Pullover Barbell · Pectorals Barbell Decline Wide-Grip Press Barbell · Pectorals Barbell Front Raise And Pullover Barbell · Pectorals Barbell Guillotine Bench Press Barbell · Pectorals

Equipment Alternatives

Don't have dumbbell? These target the same pectorals with different equipment.

Cable Decline Fly Cable · Pectorals Floor Fly (with Barbell) Barbell · Pectorals Lever Seated Fly Leverage Machine · Pectorals

FAQ

What muscles does the Dumbbell Decline One Arm Fly work?

The Dumbbell Decline One Arm Fly mainly works your pectorals. Your shoulders also works to help support and steady your body. Using good, smooth form makes sure you work the right muscles and avoid unnecessary strain on your joints.

What equipment do I need for the Dumbbell Decline One Arm Fly?

You do the Dumbbell Decline One Arm Fly with a dumbbell. Make sure your equipment is set up safely before starting. If you work out at home or have limited gear, check out our alternative exercises below.

What form mistake should I watch for on the Dumbbell Decline One Arm Fly?

One mistake to watch for is turning fly into a press: Keep the demonstrated elbow bend instead of repeatedly bending and straightening the elbows to press the load.. Use a comfortable range and a controlled return; reduce the load if you cannot maintain the demonstrated setup.

How many sets and reps should I perform on the Dumbbell Decline One Arm Fly?

To tone and grow muscle, do 3 to 4 sets of 10 to 15 smooth reps with 60 seconds of rest, focusing on a full stretch and squeezing the muscle at the top of each rep.

What's a good alternative to the Dumbbell Decline One Arm Fly?

The Cable Decline Fly trains your pectorals with cable and a similar movement pattern. Review its form guide before substituting it, since setup and range of motion can differ.