Single-Arm Dumbbell Fly
Trains the Pecs.
- Equipment
- Dumbbells and either a flat bench or an adjustable bench
- Mechanic
- Isolation
- Force
- Push
- Level
- Beginner
How to do it
- Lie on a flat bench with one dumbbell held over your chest, palm facing inward.
- Rest the free hand on your hip or your stomach.
- Set a small bend at the working elbow and hold it.
- Open the arm out to the side in a wide arc until you feel a stretch across that side of the chest.
- Bring it back over the chest along the same arc.
- Finish the repetitions on that side, then swap and match them.
Common mistakes
- Letting the body roll toward the working side. One dumbbell out to one side is a rotation the trunk resists for the whole set, and rolling is that resistance being given up.
- Reaching across the body at the top. The arc finishes over the same-side chest, not over the middle of the torso — crossing over adds range the shoulder pays for.
- Taking half your two-dumbbell weight. The trunk has more to do here and it usually runs out first.
- Holding the bench with the free hand and pulling. Resting it is fine; pulling on it cancels the anti-rotation work that made the single-arm version worth choosing.