Reverse Pec Deck
The reverse pec deck is a seated rear-delt fly on a pec-deck machine: with your chest against the pad, you sweep the handles out and back in a wide arc. It isolates the rear (posterior) deltoids, with the mid-back muscles assisting, and the chest pad removes any need to balance or brace a hinge.
Also called: Reverse Fly Machine, Machine Rear Delt, Rear Delt Machine, Pec-Deck Rear Delt Fly · Equipment: machine · Pattern: isolation
Step by step
- Set the machine's handles to the rear-delt position and adjust the seat so the handles are level with your shoulders.
- Sit facing the machine with your chest against the pad and your feet flat on the floor.
- Reach forward and take the handles with your palms facing down, arms nearly straight with a slight bend in the elbows.
- Pull your shoulders down away from your ears.
- Sweep your arms out and back in a wide arc, leading with your elbows, until your arms are in line with your body.
- Pause briefly, then let the handles travel forward under control until you feel a stretch across the backs of your shoulders.
- After the last rep, return the handles slowly to the start before letting go.
- Lead with your elbows
- Shoulders down, away from your ears
- Arms wide, in line with your body at the back
- Chest stays on the pad
- Control the return to the stretch
In VALDA, these cues are one tap away on the exercise while you train.
What it trains
| Muscle | Role | Evidence |
|---|---|---|
| Posterior deltoid: posterior | Prime mover | C |
| Rhomboids | Secondary | C |
| Trapezius: middle | Secondary | C |
| Trapezius: lower | Stabiliser | D |
| Rotator cuff | Stabiliser | D |
Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.
What goes wrong, and the fix
Shrugging as you pull
Fix: Pull your shoulders down before the first rep and keep them there.
Pulling the hands behind the body
Fix: End the sweep when your arms are in line with your body.
Elbows bending as you pull
Fix: Keep a fixed slight bend in your elbows throughout the sweep.
Chest leaving the pad
Fix: Keep your chest pressed into the pad for every rep.
Seat at the wrong height
Fix: Set the seat so the handles sit level with your shoulders.
What the research says
Muscle growth · first choiceRehab & prehab · first choiceGeneral fitness · first choiceEndurance
- Range and tension — Reviews find full-range training favours muscle growth most clearly in the legs. Upper-body evidence is limited, so the benefit of the machine's more even tension for the rear deltoids is reasoned rather than measured.
- Machines and free weights — A meta-analysis found machine and free-weight training produce similar muscle growth, while strength gains are specific to the equipment trained on.
- Load and effort — Studies show muscle growth is similar across a wide range of loads when sets are taken close to failure, and sets that finish a rep or two short of failure capture most of that benefit.
- Volume and frequency — Research links more weekly sets for a muscle to more growth, with diminishing returns, and training a muscle about twice a week is a common way to spread that volume.
- Sets and reps — A common approach is 2–4 sets of 10–20 reps, often paired with a pressing or lateral-raise exercise.
Swap it mid-workout
- Cable External Rotation
- Cable Bent-Over Lateral Raise
- Cable Face Pull
- Cable Rear Delt Fly
- Dumbbell Rear Delt Fly
- Barbell High Pull
With VALDA Pro, FLEX offers alternatives like these when you swap an exercise mid-workout.
Log the reverse pec deck in VALDA, with these cues one tap away while you train and your history for it in one place.
General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.