Dumbbell One Arm Bench Fly
Dumbbell One Arm Bench Fly Exercise Description
The Dumbbell One-Arm Bench Fly is a unilateral chest exercise performed supine on a flat bench. It emphasizes horizontal shoulder adduction, making the pectoralis major the prime mover, with the anterior deltoid assisting. The rotator cuff and scapular stabilizers maintain humeral head alignment as you move, while your trunk resists rotation from the single-sided load to keep you square on the bench. Because this drill uses a long lever arm, it demands a slight, consistent elbow bend, a neutral wrist, and a conservative depth to keep the stress on the chest rather than the front of the shoulder. Training one side at a time helps you focus on smooth control and equal range of motion on both arms without turning the movement into a press.
- Muscle Groups: Chest, Pecs
- Target Muscles: Pectoralis Major - Sternal Head
- Assisting Muscles: Deltoid - Anterior
- Stabilizing Muscles: External Obliques, Infraspinatus, Subscapularis, Trapezius - Lower Fibers, Trapezius - Middle Fibers
- Body Area: Upper Body
- Body Parts: Chest
- Body Surface: Front
- Body Symmetry: Unilateral
- Equipment: Bench, Dumbbell
- Exercise Patterns: Other
- Exercise Type: Strength
- Functional Grouping: Horizontal Shoulder Adduction
- Joint Involvement: Single-joint
- Muscle Location: Mid Chest
- Movement Direction: Other
- Muscle Position: Anterior
- Gender: Male
How To Do The Dumbbell One Arm Bench Fly Exercise
‘- Lie on a flat bench with feet planted, head/upper back/hips in contact. Lightly brace your midsection.
– Hold one dumbbell above mid-chest with a neutral grip (palm facing in). The other hand can lightly hold the bench for stability.
– Set your shoulder blades gently down and together (scapular depression/retraction). Keep the working shoulder “packed.”
– Start with the elbow softly bent about 15–30 degrees; keep this angle nearly constant throughout.
– Keep the wrist neutral (knuckles in line with forearm) and the dumbbell centered over the chest, not the face.
– Lower the dumbbell in a wide arc out to the side, maintaining the same elbow bend and shoulder packing. Control the descent.
– Stop when the upper arm is roughly level with your torso or when you feel a comfortable chest stretch—avoid shoulder discomfort or letting the shoulder roll forward.
– Squeeze the chest to reverse along the same path, bringing the dumbbell back over mid-chest. Do not turn it into a press.
– Keep hips level and ribcage down; resist rotating toward the loaded side.
– Finish each rep with the shoulder down away from the ear and the forearm vertical above the chest.
– To enter/exit safely, use both hands to position or lower the dumbbell, or request a spot if needed.
Dumbbell One Arm Bench Fly Tips
‘- Keep your feet planted and head, upper back, and hips in contact with the bench for a stable base.
– Lightly brace your midsection before you start and maintain that tension throughout the set.
– Hold the dumbbell over mid-chest (not your face) with a neutral grip and a neutral wrist.
– Lightly hold the bench with your non-working hand to help stabilize your body.
– Gently pull your shoulder blade down and together and keep the working shoulder “packed” as you move.
– Start with a soft 15–30° elbow bend and focus on keeping that angle nearly constant during the arc.
– Lower the dumbbell in a wide, controlled arc, maintaining shoulder packing and the same elbow bend.
– Stop the descent when your upper arm is roughly level with your torso or at a comfortable chest stretch—avoid any shoulder discomfort or rolling forward.
– As you raise the dumbbell, squeeze your chest and follow the same path back, resisting the urge to press straight up.
– Keep your hips level and ribcage down to resist rotating toward the loaded side, and finish each rep with the shoulder down away from the ear and the forearm vertical over your chest.
Dumbbell One Arm Bench Fly Beginner Introduction
The Dumbbell One-Arm Bench Fly is a lying, single-dumbbell chest fly variation that highlights one side of the body at a time. Done on a flat bench, it centers on the arm sweeping out to the side and then back over the chest, so the chest muscles do most of the work while the front of the shoulder assists. Because the weight is held in only one hand, the midsection and hips also play a role, working against the urge to twist so the torso stays aligned on the bench.
This movement has a long arm reach, so tension spreads through the chest in a wide arc rather than feeling like a press. A slight bend at the elbow and a straight line from knuckles to forearm help place the effort where it belongs instead of stressing the front of the shoulder joint. The shoulders and upper back contribute by guiding the upper arm smoothly and keeping the joint centered as the weight moves through its path, encouraging controlled motion and an even range on both sides of the body.