Pec deck

The pec deck is a chest fly on a fixed path. Your back is against a pad, your hips are seated, and the machine decides where your arms travel. That removes almost everything except the work.

Because nothing balances and nothing can tip over, it is the chest exercise most people can push nearest to failure without the set turning into a fight.

Sets, reps and RIR

Machines and cables hold the path for you, so you can work closer to failure than with free weights.

RIR means reps in reserve: how many you could still have done when you racked it. RIR 2 is two short of failure.

How to do it

1. Set the seat so the handles sit at roughly chest height when you are sitting upright.
2. Sit back with your whole spine against the pad and both feet flat on the floor.
3. Take the handles with the elbows slightly bent and the upper arm in line with the shoulder.
4. Bring the handles together in front of your chest and hold for a moment at the point where it is hardest.
5. Let the arms open again under control, and stop when you feel the stretch rather than when the weight stack lands.

Common mistakes

Seat at the wrong height

Handles too high and the front delt takes over. Too low and it turns into a pulldown. Shoulder and handle in the same horizontal line is the reference point.

Letting the stack land

If the plates touch at the back of every rep, the tension resets and you start the next rep from nothing. Stop just short.

Shoulders rolling forward at the top

Hunching to squeeze the handles together shortens the chest with the shoulder instead of the arm. Shoulder blades stay against the pad.

Rushing the stretch

Dropping fast into the open position loads the shoulder at its least comfortable angle. Slow down for the last part of the way out.

How it differs from the neighbouring variants

The cable crossover is the same movement without the fixed path. It costs you stability and gives you a choice of angle. The pec deck wins when the goal is to get close to failure safely.

A dumbbell fly loads the stretched position hardest and goes nearly weightless at the top. The machine keeps something on the muscle all the way through.

What it suits

The pec deck goes after your pressing, or as the whole chest session on a day when your shoulders are sore and pressing is not appealing. Ten to twenty reps, and zero to one rep in reserve on the last set is reasonable here, since a failed rep costs you nothing but the handle coming back.

Muscles worked

Primary: Chest.

Secondary: Front delts.

Estimate your one-rep max

Epley's formula, from a set you have actually done. It is an estimate, and it drifts above eight reps, so keep the input between one and twelve.

What it is called elsewhere

• Norsk Pec deck
• Svenska Pec deck
• Dansk Pec deck
• Deutsch Butterfly (Maschine)
• Español Aperturas en máquina
• Italiano Pectoral machine
• Português Peck deck (voador)
• Русский Сведение рук в тренажёре бабочка
• Français Pec deck

Related chest exercises

• Bench press (barbell)
• Incline bench press (barbell)
• Decline bench press (barbell)
• Close-grip bench press (barbell)
• Landmine press
• Flat dumbbell press

athlate logs this exercise, keeps the numbers, and tells you what you lifted last time.