The Pec Deck: Your Ultimate Guide To a Well-Defined Chest

Whether you’re training for aesthetics- wanting a muscular, toned physique- or for performance- going for a functionally strong torso- you will want to develop your chest. This means working your pectorals hard, through a range of motions and stimuli.

However, there are too many types of chest exercise to count, and it can all be a little overwhelming as you try to program your training sessions. Presses are a good bet: bench press, chest press, push ups and dips should all form core parts of your chest routine. However, for a bit of extra pump- to really put the stimulation into your pectorals in near enough isolation- pec decks are a firm favourite in gyms around the world.

Pec decks do a good job of isolating your pecs, meaning that you can really work on muscular contraction, neuromuscular control and vascularity across them. They are also perfect for all levels: experienced athletes can make the most out of them, but so can beginners, as they take a relatively low amount of skill or experience to perform correctly.

In this article, we’ll look at some of the benefits- and some of the downside- that come with using the peck deck, as well as going through proper form and programming best practice.

Benefits Of Using The Pec Deck

Pec decks are amongst the best machines for specificity when it comes to training the upper body. They are designed solely to allow you to increase the strength and size of your chest muscles. Specifically, it works the pecs (hence the name), though a fair amount of stimulation often also goes into supporting muscles like the anterior deltoids: all the muscles that are used when bringing your arms together in front of your body see some use with the pec deck.

With this in mind, the pec deck is indeed amongst the best exercises you can find for eliciting hypertrophy in your pectorals. It additionally strengthens your torso and brings a great stabilising factor to your shoulder blades, opening up supporting muscles like the serratus anterior for activation.

The movement itself is simple and, as it’s a machine with limited range of motion, hard to get wrong (though it’s best to begin light as you get used to it.) Whilst complex compound exercises like the bench press or dip take a fair amount of skill and practice to complete safely and effectively, the pec deck can be used from day one by any beginner in the gym.

This all being said, let’s look with a little more detail at the pros and cons of including the pec deck in your regular workout programming.


There are a number of advantages to be gained from regularly using a pec deck machine. If you perform the exercises well, under control, and keep the movements steady, the pec deck will allow you to reap a great many rewards:

  • They are great for building the often-neglected inner chest. This can be quite a hard portion of the chest to activate using large, compound movements like the bench press. Leaving it out could result in muscular imbalances, which will have a negative impact on both the functionality and aesthetic quality of your pectorals.
  • With this in mind, pec decks are amongst the best isolation movements available for your chest. Use them towards the end of an upper body workout as assistance finishers to really work on hypertrophy.
  • The muscle you will build here will have carry over into other exercises: most, if not all, compound exercises really in some way on having a strong, muscular torso, towards which the pec deck can greatly contribute.
  • The pec deck is easy to use, making it ideal for beginners bringing in the first of their hypertrophy gains in their upper bodies. They won’t need much by way of skill or instruction and will simply be able to enjoy the mass building.
  • The pec deck also isn’t very demanding on the central nervous system (CNS), making it great for those just building up their workout volume tolerance, or for those, as above, looking to finish off their chest workout after performing larger movements.


However, there are some disadvantages to using the pec deck. In fact, many trainers and athletes swear off them entirely, and their carry over into functional athleticism and actual strength gains are questionable (CITE.) They can be considered unsafe at the worst and ineffective at the best.

The cons of using the pec deck include:

  • The pec deck will put your shoulders into quite a precarious position, akin to bench pressing with the bar too far towards the head end of the bench: from here, your shoulder blades and deltoids can be prone to injury and are at a risk of destabilisation.
  • Though the pec deck may be used to work the inner chest, it only actually works a portion of it. It works the lower portion of your chest far more than the mid- and upper- chest. Though this isn’t necessarily a bad thing- especially if you balance it with upper chest moves like the incline bench press- it is something to bear in mind for those with a tendency to overuse the peck deck.
  • The lack of CNS fatigue could in fact be a negative. We saw above that this fact makes the pec deck good for those looking for a less stimulating exercise. However, a less stimulating exercise is… less stimulating. It may work the individually targeted muscles hard, but it won’t contribute to workload capacity or upper body strength in any meaningful way. Nor can anything so unstimulating build muscle in the long run.
  • Compound movements have their own advantages that cannot be captured by isolation moves, especially those using limited range of motion machines like the pec deck. Don’t rely on the pec deck as an upper body builder- this should be left to large, compound moves like the bench press, dip, and push up. Only use it in a minor capacity, as an assistance or finishing exercise.
  • The pec deck forces you into a range of motion, as do all such machines. If your body doesn’t comfortably fit this range- and most don’t, as we all enjoy varied body mechanics- then you could be forcing your joints into compromised positions, under load. This can lead to short term injuries and longer-term imbalances and soft tissue damage.

Every exercise will have its own pros and cons. So too will every machine (and a large con with a machine is that it’s a machine, with limited function and range of motion.) However, it’s ultimately up to whomever is writing your programme- or even you, yourself- to decide what to include. The pec deck has its place, and can be used to great effect: just don’t rely on it, overuse it, or build a workout around it.

How To Use The Pec Deck

How To Use The Pec Deck

The whole point of resistance machines is that they are easy to use. Beginners and untrained individuals can jump straight on them and get something of a decent workout without having to learn any of the big lifts or figuring out how to navigate the weights room.

The pec deck is no different: it’s easy to use and hard to mess up.

However, there are some tips to follow when you’re using it. To properly execute pectoral flyes on a pec deck:

  1. Adjust the equipment so that the seat is at the right height, or the pads are in a comfortable position. You should be able to adjust it so that your feet are on the floor, the back is supported, and your elbows and wrists are pretty much level with your shoulders.
  2. Your arms should always be in front of you, even if only slightly: you never want them to come behind your body under load. Your elbows should be slightly bent at extension, never locked out. You may need to adjust the arm levers.
  3. Find an appropriate weight setting. Start off on the lighter side and go for 10-12 reps. Then, gradually bring the weight up as you find what works for you. You should never struggle to finish a rep with good form, but the appropriate weight will make you fatigue at the 10-12 rep point, finding it hard to carry on into the last couple of reps.
  4. Now, you’re ready to go through the movement. You want to think of it like slowly clapping your hands, or like a bird flapping its wings in slow motion. Grip the handles, or align your arms on the pads, sit up tall, with relaxed shoulders and neck, and keep your feet firmly planted on the ground. Bring your arms in, so that your hands come to within an inch or so of one another.
  5. Keep a slight bend in your elbows and keep your wrists relaxed throughout.
  6. Go for 3-4 sets of 10-12 reps, or as many sets and reps as your program dictates.

Common mistakes

There are some common mistakes that beginners- and some more advanced athletes- typically make when using the pec deck. These include

Holding the breath

This isn’t a power move in which a good breath and brace is needed. You shouldn’t be tense at all, nor should you cut off your oxygen flow- you have lots of reps to get through. Breath out slowly as you bring your hands together, breath in again as you release them back to the starting position.

Using the legs

Again, this isn’t the bench press where leg drive is a much-needed element. It’s an isolation move and should therefore be used to isolate the pecs. Don’t use your legs. If the weight is too high to shift it with your arms alone, bring the weight down. All effort should be coming from your pecs.

It may also be tempting to press into your feet to steady your body and give that closing movement more power. But remember, the purpose of this exercise is to train the chest muscles, not your legs. If you notice that you are using your legs to gain momentum, decrease the amount of weight you are lifting.

Arching the back

One last time, this isn’t the bench press: you don’t want an arch in your back. Your back should be flat against the seat and well-supported. If you can’t manage this, it’s because the weight is too high and you are trying to compensate using favourable body mechanics. Bring the weight down.

Modifications, Variations And Alternatives

Modifications, Variations And Alternatives

Not all machines are created equal, and not every lifter needs the same thing: there are plenty of different ways of performing a chest flye, both with a pec deck and without.

Let’s start with modifications and variations of the pec deck. Some will have different attachments and positionings, some will use different mechanisms, and some will put you into different positions. For example, it’s common enough to see both variations in which you have to hold onto handles to move through the exercise, and variations in which you line your forearms up on pads. Some will give you an adjustable seat, whilst some seats will be fixed and the mechanism itself will be adjustable.

However, the same basic rules will apply: follow the technique listed above and you shouldn’t go far wrong. If in doubt, always feel free to ask a trainer or member of staff to show you how you local gym’s pec deck works.

There are also different things you can do with a pec deck. Two of the most effective variations include:

  1. Hitting your obliques. Use one arm at a time, keeping the other arm neutral at your side. You will feel your feet working harder to stabilise your torso, and your core will come into play to counter the motion.
  2. Super-setting for a pre-exhaust. If you want to make the most of both compound and isolation movements, super sets are a great way to go. Pec decks work excellently here. Try completing a set of 10-15 push ups straight before using the pec deck: you will fatigue your chest, shoulders and arms quite globally, before going on to really emphasise your pecs.

There are other ways to perform flyes. Perhaps you don’t have access to a pec deck: you train at home, where equipment is limited, or your gym simply doesn’t have one. Don’t worry: there are plenty of ways to hit your chest.

To replicate the effects and feel of a pec deck, you can:

  • Use dumbbells to perform dumbbell flyes. Lie on a bench with light dumbbells in your hands, above your head, palms facing one another. Lower the dumbbells out to the side, in the same butterfly motion that the pec deck uses. Bring them down until they are just above level with your chest, then reverse the motion.
  • Use kettlebells for kettlebell flyes. Use these exactly as you would dumbbells, with the same starting and end points, the same technique, and similar weights. However, hold the handle straight up, with the weight on the outside, so that it starts off resting on your outer forearm.
  • Use cables for cable flyes. Take a handle attachment in each hand, stand up in a neutral position, with the cables set to chest height. Bring your hands up and in front of your chest, together, with your palms facing one another. From here, perform that same butterfly motion, not allowing your hands to come behind your chest.

And there we have it: everything you need to know to begin using the pec deck. You should hopefully know a little about the uses, pros and cons of the pec deck, as well as how to go about setting one up and incorporating it into your training regime.

If your gym doesn’t have a pec deck machine, or if you read the cons list and decided you wanted to try something different, the above exercises should all elicit similar results in terms of hypertrophy, strength gain and muscular activation.

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James Dixon

James Dixon is a fully qualified personal trainer and award winning writer, with a decade’s worth of experience under his belt. Throughout his career, he has helped hundreds of people to meet their dietary and fitness goals, writing exercise and nutrition plans to suit any and every requirement.

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