Upper body · Shoulders

Reverse pec deck

How to train the rear delts on a reverse pec deck: setup, arm position, range of motion and why it helps posture and shoulder health.

The reverse pec deck is done sitting facing the back pad of a pec deck machine, opening your arms backward. It trains the rear delts, the back of the shoulder, which tend to lag behind the front delts in press-heavy routines. Strengthening them improves the look of the shoulder and helps posture.

Muscles worked

The rear deltoid brings the arms back. The rhomboids and mid traps assist by squeezing the shoulder blades.

How to do it

1. Sit facing the back pad of the machine, chest against it.
2. Set the handles in front of you at shoulder height, arms almost straight.
3. Grip the handles with a neutral or overhand grip and your elbows slightly bent.
4. Open your arms back in an arc until they line up with your body.
5. Return slowly without letting the plates touch.

Common mistakes

• Squeezing your shoulder blades hard: the work shifts to the mid back. Think "open the arms", not "squeeze the back".
• Taking the arms far behind your body.
• Too much weight, forcing you to use momentum.
• Lifting your chest off the pad.

Variations

• Dumbbells, bent over or chest-supported on an incline bench.
• Cable face pull: adds external shoulder rotation.

It works well for 12–20 controlled reps.

Precautions

It only loads the shoulder, with light weight. It is usually well tolerated even when pressing exercises bother your shoulder.

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