Chest Exercise · Dumbbell

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Dumbbell One Arm Bench Fly

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

Category

Chest

Equipment

Dumbbell

Target

Pectorals

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Biomechanical cues verified by the PlanWorkouts Science Review Board under CSCS editorial oversight; see our editorial standards.

Flying with one arm at a time isolates each side of the chest fully, without a stronger side finishing the rep for a weaker one the way a two-arm fly can allow. It also forces the core and opposite side of the body to stay braced against the pull of the working arm. This unilateral approach is worth using specifically to correct a chest imbalance.

How to Do the Dumbbell One Arm Bench Fly

1. Sit on a flat bench holding a dumbbell in one hand, resting it on your thigh.
2. Recline back onto the bench while keeping the dumbbell pressed against that thigh.
3. Use your free hand to help guide the dumbbell up into the starting position.
4. Position the dumbbell directly above your shoulder with your arm straight and palm facing inward.
5. Lower the dumbbell out to the side in a wide arc, allowing a slight bend at the elbow.
6. Hold briefly once your arm is level with the floor, then reverse the arc back to the start.
7. Continue for your target number of reps, then switch arms and repeat.

Biomechanical & Joint Load Cues

Single-joint horizontal adduction isolating the sternal and clavicular pectoralis fibers without triceps tricep fatigue limiting set termination.

Common Mechanical Mistakes & Form Errors to Avoid

• Bending Elbows into a Press: Excessively bending elbows into 90 degrees during flyes turns the movement into a press, recruiting triceps instead of isolating pectorals.
• Overstretching the Shoulder Capsule: Dropping arms too far behind the torso plane strains the anterior capsule without adding meaningful pec activation.
• Rushing the Converging Squeeze: Failing to pause briefly at peak contraction in front of the chest misses the maximal short-muscle fiber recruitment.

Proper Breathing Patterns & Core Engagement

Inhale as arms open into full chest stretch; exhale as hands converge in front of the chest.

Injury Modification & Joint Safety

Do not overstretch past comfortable range in the bottom position if you have a history of anterior shoulder subluxation or AC joint sprain. If joint irritation persists, immediately stop and substitute this movement with another exercise from the Chest exercises category.

Muscles Worked

The Dumbbell One Arm Bench Fly primarily targets the Pectorals, with Shoulders as the primary synergist muscle group.

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.

Chest And Front Of Shoulder Stretch Body Weight · Pectorals Barbell Bench Press Barbell · Pectorals Behind Head Chest Stretch Assisted · Pectorals Cable Bench Press Cable · Pectorals

FAQ

What muscles does the Dumbbell One Arm Bench Fly work?

The Dumbbell One Arm Bench Fly primarily targets the pectorals as the primary agonist. The shoulders acts as the primary supporting muscle group during force transmission. Maintaining strict biomechanical alignment ensures maximal tension remains focused on the intended muscle fibers rather than shifting to surrounding stabilizer joints.

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

The Dumbbell One Arm Bench Fly is performed using a dumbbell. Ensure all equipment is securely positioned with collars or safety pins locked before loading working sets. If you train in a home gym or minimal setup, explore our equipment-free and resistance band alternatives below.

What is the most common form mistake on the Dumbbell One Arm Bench Fly?

The most frequent error is bending elbows into a press: Excessively bending elbows into 90 degrees during flyes turns the movement into a press, recruiting triceps instead of isolating pectorals.. Controlling the 2 to 3-second eccentric lowering phase ensures maximal hypertrophic stimulus while shielding connective tissue.

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

For muscle growth and density, execute 3 to 4 working sets of 10 to 15 controlled repetitions with 60 seconds rest, emphasizing a deep stretch and deliberate peak contraction on every rep.

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

If you don't have access to a dumbbell, the Chest And Front Of Shoulder Stretch targets the same pectorals using body weight instead. This alternative replicates the same joint angle and movement plane while allowing you to train effectively with different available gear. You can also substitute it seamlessly in our free Workout Plan Builder.