chestintermediateReviewed by Dr. Ananya Iyer, DPT

Flat Dumbbell Fly

Classic stretch-mediated hypertrophy movement for chest width.

Recommended Sets3 Sets
Rep Range10–12 Reps
Rest Period60s Rest
Equipmentdumbbell, bench

3D Visual Form & Technique Demonstration

Biomechanically verified form execution and joint angle cues.

Official Video Tutorial · 3D Biomechanics & Form DemonstrationWatch on YouTube
How to Execute the Flat Dumbbell Fly

Lie on flat bench holding dumbbells directly above chest with palms facing each other. Slightly bend elbows and maintain this fixed angle throughout.

  • Primary Muscle: CHEST
  • Secondary Synergists: FRONT-DELTS
  • Rest Interval: 60 seconds between sets

Flat Dumbbell Fly Anatomy Activation

Primary motor unit recruitment for chest with secondary synergist stabilizers.

Primary (chest)
Secondary Synergists
Anterior (Front View)
Anterior Muscle Recruitment: chestFront anatomical silhouette highlighting chest in orange as active agonist.
● Primary Target View
Posterior (Back View)
Posterior Muscle Recruitment: chestBack anatomical silhouette highlighting chest in orange as active agonist.
Secondary / Stabilizer View
Anatomical PlaneTransverse Plane
Primary KinesiologyHorizontal Adduction
Biomechanical VectorMedial converging force towards the sternum
Active Anatomy:Primary: chestSynergist: front-delts
Figure: Biomechanical muscle recruitment model for chest. Highlighted in orange is the primary agonist motor unit; highlighted in blue are synergistic stabilizing groups (front-delts).

Step-by-Step Execution Guide

1

Lie on flat bench holding dumbbells directly above chest with palms facing each other.

2

Slightly bend elbows and maintain this fixed angle throughout.

3

Lower dumbbells outward in wide arc until feeling deep chest stretch.

4

Bring weights back together using pectoral contraction.

Common Mistakes & Form Fixes

Lowering dumbbells too far below bench level risking shoulder strain.

Straightening arms into a press.

Biomechanical Safety & Injury Warning

Do not use excessive load; focus on stretch and mind-muscle connection.

Alternative Exercises & Swaps

If the equipment is occupied or you need a joint-friendly variation, substitute with these approved movements:

Rohan Varma, CSCS
Authored By
Rohan Varma, CSCSHead Strength Coach & Biomechanics Lead
Dr. Ananya Iyer, DPT
Medically Reviewed By
Dr. Ananya Iyer, DPTChief Medical & Biomechanics Reviewer
Last Reviewed & Verified: 2026-03-29
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