Muscle man gym training pec deck chest machine flye

Use the pec deck to build a bigger and broader chest

Most gyms have a pec deck machine, but most gym-goers don’t use them properly and fail to build the bigger, broader and more defined chest they want. Here’s how to use the pec deck machine smarter to get the better upper-body results you want, says New Body Plan fitness director Joe Warner

If you want to build a bigger and more defined chest then only ever doing the barbell bench press isn’t the right approach.

Yes, doing this move, or a similar variation such as the machine chest press, will help you add muscular size and strength. But unless you include a range of different exercises that work your chest muscles through different angles and different movement patterns you’re never going to build the impressive pecs you want.

It’s a bit like eating your vegetables: you should consume a wide range of different types to get the maximum health benefits. And it’s the same with chest training: variety is your new secret shortcut to big-chest success.

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And that’s where the pec deck comes in to its own. Why? Because it works your chest muscles in a very different way to all chest-pressing exercises, and helps sculpt size and definition on the outer and inner parts of the chest.

And it’s developing new muscle mass in these areas that can really make your pecs “pop”. So use the advice below to get more out of the pec deck machine and build the bigger, broader and more defined upper body you want!

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What is the pec deck machine?

The pec deck machine (sometimes called a seated machine flye) can be found in most gyms. It’s a very popular machine and for good reason. It’s one of the best bits of kit for working your pectoral – or chest – muscles. There are multiple types of pec deck machine, but two are most common.

The first is a machine with a seat in front of a pin-adjustable weight stack, with two “arms” attached to a pulley system linked to the weight plates.

The position of these arms can be adjusted through a simple pin mechanism to expand or restrict the range of motion these arms can move through. In this type of machine your elbows aren’t locked into position so you need to keep them positioned correctly when doing the exercise.

Some of this type of pec deck are “reversible”, in that you can sit on them the other way around and move the arms back and behind you to work the muscle of your upper back in a similar way to the dumbbell reverse flye.


What’s the other type of pec deck machine?

The other main type of machine you sit in too, but it has two arms with handles that you grip around head height. Your forearms press against pads so that your elbows are locked in position by the machine. You then use your chest muscles to bring your forearms together to meet in front of your chest, then reverse that movement back to the start.

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How does the pec deck machine work?

All pec deck machines work in a very similar way. You sit on the seat, grip the handles, then contact your chest muscles to move your arms forward in a smooth arc until your hands meet in front of your body. The movement pattern this machine uses to work your chest muscles is similar to that of other moves, specifically the dumbbell bench flye and the standing cable flye. See below for a complete guide to using the pec deck.


What muscles does the pec deck machine work?

The primary muscle that gets worked is the pectoralis major, which is the anatomical name for the main muscle of the chest. It’s a large, fan-shaped muscle. It sits on top of the pectoralis minor, a smaller, thinner and triangular-shaped muscle, which is also trained when using the pec deck.


What other muscles does the pec deck work?

The anterior deltoids (or front shoulder muscles) are also involved in the exercise, just as they are in all pressing exercises that primarily target the chest, such as the incline dumbbell bench press.

The biceps also get in on the act if you are using a pec deck in which you grip head-height handles with your forearms against pads, because your biceps need to bend your elbows to get into the start position and maintain this position for the duration of the set. But the biceps aren’t activated in pec decks in which your arms start and stay in either a straight, or only slightly bent, position.


Why can’t I lift as heavy on the pec deck as with the machine chest press?

The pec deck essentially “isolates” your chest, which means that this muscle must do all the work. This limits how much weight you can lift. In the machine chest press, and all other chest-pressing moves, the chest is supported by the shoulder and triceps muscles, which means a greater total weight can be lifted.

It’s just like how you can lift far more when doing an underhand lat pulldown compared to a wide-grip lat pulldown, because your biceps help out in the former, whilst your back muscles must do all the work in the latter.

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How do I use the pec deck machine?

Note: there are many different pec deck machines, each with their own mechanism and settings, so always refer to the machine’s instructions before use

• Adjust the seat and arm settings on the machine. The seat should be set so that when you bring the arms of the machine together they meet in front of the middle of your chest. The machine’s arms should be set so that you feel a good stretch across your chest in the start position.
• Sit back on the seat with your bum and back pushed into the padding. Press your feet into the floor.
• Take hold of the handle at the end of each of the machine’s arms. Grip them hard. • Ensure your chin is raised so your head is in a neutral position and you’re looking straight forward.
• Tense your abs to keep your torso stable, and push your shoulder blades back to lift your chest. This is the start position.
• Keeping a slight bend in your elbows, bring your hands together in a smooth arc until they meet in front of your chest.
• Pause and squeeze your chest muscles hard for at least one second.
• Slowly reverse the arc movement back to the start position, controlling the weight for the whole time. If you let gravity take over the handles can swing back too far, placing excess strain on your chest and shoulder muscles as well as your shoulder, elbow and wrist joints.

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What are the best alternatives to the pec deck machine?

If your gym doesn’t have a pec deck you can replicate the machine’s muscle-building impact with other machines or bits of kit. Here’s some of the best pec deck machine alternative options.

Standing cable flye

The cable flye works your chest and front shoulder muscles in a very similar way to the pec deck machine. One key difference is you’re standing up, so many small stabilising muscles are also recruited, not least your abs, to keep your body in the correct position. A split-foot stance, with one foot forward, makes balancing easier, especially as the amount of weight you’re lifting gets heavier.

Standing cable crossover

The cable crossover is similar to the cable flye, except the handles are attached to the high pulley or the low pulley rather than pulleys at chest height. This changes the angle of the movement and involves the front shoulders more. You also cross your hands in front of your body, rather than them just touching in the middle, and this forces a greater contraction of your chest muscles. Remember to alternate which hands passes in front of the other with each rep.

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Flat bench dumbbell flye

Using dumbbells requires a greater focus on safety, because your delicate shoulder joint can be exposed to excess stress during the lowering phase of each rep. Going too heavy can also risk injury to the pectorals. Always focus on perfect form, even if it means you have to reduce the weight of the dumbbells you use.

Incline bench dumbbell flye

Lying on an incline bench changes the angle of attack to work your chest muscles through a slightly different range of motion to hit different parts of the muscle with greater intensity. But as with the flat bench flye, never start too heavy and always ensure your chest muscles, as well as your shoulder joints, are fully warmed up before starting a set.

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