Upper body · Chest

Pec deck fly

How to do the pec deck fly: seat height, arm position, a shoulder-safe range of motion and common mistakes.

Technique video

The pec deck, or fly machine, trains the chest with a hugging motion: your arms come together in front of your body with the elbows almost fixed. Unlike presses, the triceps barely work, so the chest does all the work. It is a good follow-up after a press, or a chest option when your elbow or wrist bothers you.

Muscles worked

It isolates the pectoralis major, especially its role in bringing the arm toward the midline. The front delts assist.

How to do it

1. Adjust the seat so the handles or pads are at mid-chest height and your arms are almost parallel to the floor.
2. Keep your back against the pad and squeeze your shoulder blades lightly.
3. Grip the handles with your elbows slightly bent.
4. Bring your arms together in front of your chest in an arc, as if hugging a tree, and squeeze for a second.
5. Return slowly until you feel a moderate stretch in your chest, without letting your arms go behind your body.

Common mistakes

• Opening the arms too far on the way back, stressing the front of the shoulder.
• Seat too low, with your hands above your shoulders.
• Leaning off the back pad to push.
• Using momentum and letting the weight snap back.

Variations and progression

The cable crossover does the same movement standing and lets you vary the angle. Facing the machine the other way (chest to the pad) trains the rear delts. It works well with 12–20 controlled reps.

Precautions

It only loads the shoulder, with light weight. If you feel discomfort at the end of the stretch, shorten the range on the way back.

If you have an injury, pain or a medical condition, check with a professional before doing this exercise.