Chest Fly Machine: How to Use It, Form Tips and Home Options

A chest fly machine is a seated machine where you push two handles (or forearm pads) together in an arc in front of your chest, which isolates your pecs without the shoulders and triceps taking over the way they do on a press. You'll also see it called a pec fly, pec deck or butterfly machine. To use one well you need three things right: a seat height that puts the handles at mid chest, a soft and fixed elbow bend, and a range of motion that stops before your shoulders roll forward. Below is how to set it up, what it works, the mistakes that cost you results, and which home multi gyms and cable machines give you the same movement without paying for a commercial unit.

What a chest fly machine actually is

There are really four machines that people mean when they search for this, and they don't feel the same.

Machine	How you push	Also does	Typical home option
Classic pec deck	Forearms against vertical pads	Nothing else	Rare, mostly on older multi gyms
Pec fly (handle) machine	Grip handles, arms nearly straight	Nothing else	Commercial units only
Dual pec fly / rear delt	Handles rotate to face either way	Reverse fly for rear delts	Some selectorised multi gyms
Cable crossover	Two independent cables	Almost every cable exercise	Home cable towers and functional trainers

The pad version is the most forgiving on your elbows because the load sits on your forearms, but it also tends to let people shrug and roll their shoulders forward. Handle versions are closer to a dumbbell fly in feel. A cable crossover is the most flexible of the lot: you can fly from high, middle or low, one arm at a time, and the line of pull is set by where you stand rather than by a fixed pivot. If you've only got cables, our cable fly guide covers the technique in detail.

The dual machines are worth knowing about, because the reverse direction (the rear delt fly) is arguably the more useful exercise for anyone who sits at a desk all day.

How to use a chest fly machine with good form

Every brand sets things up slightly differently, but the principles carry across.

1. Adjust the seat before you load anything. Sit with your back against the pad and reach for the handles. With your upper arms roughly parallel to the floor, the handles should sit level with the middle of your chest. Move the seat until that's true rather than sliding down or perching forward.
2. Set the start position of the arms. Most machines have a pin or lever that sets how far back the handles start. Choose a position where your hands sit just behind the line of your chest, so you feel a light stretch but not a pull on the front of the shoulder. Beginners should start narrower than they think.
3. Grip and brace. Use a neutral grip on vertical handles (palms facing each other), feet flat, shoulder blades pulled down and slightly back into the pad. Keep that position for every rep; if your shoulders peel forward, the chest stops doing the work.
4. Bend your elbows slightly and lock that angle. A small bend of about 10 to 20 degrees protects the elbow and keeps the load on the pec. The angle shouldn't change during the rep, otherwise you've turned a fly into a press.
5. Bring the handles together in an arc. Think about squeezing your upper arms towards each other rather than pushing with your hands. Bring the handles to touch, or nearly touch, in front of your sternum and hold for one second.
6. Return slowly. Take two to three seconds on the way back, stopping when your hands reach the line of your torso or a fraction past it. Don't let the stack crash down between reps.

Muscles worked

The chest fly machine is a horizontal adduction exercise, so the pectoralis major does nearly all of the work. With the handles at mid chest you'll mostly load the sternal (middle and lower) fibres, while the clavicular (upper) fibres and the front of the shoulder (anterior deltoid) assist. Your biceps hold the elbow angle, and the small muscles around your shoulder blade keep you stable against the pad.

What it doesn't do is train your triceps or ask much of your core, which is exactly why it suits the end of a session when those are tired from pressing.

There's decent evidence that the machine builds muscle on its own. In a 12 week study where untrained young men trained only the pec deck, chest thickness increased by around 17 to 21% in both the upper and lower portions, and doing one set gave about the same result as three (Pinto et al., 2025, J Strength Cond Res). The same study found no sign that the machine favoured one region of the chest over the other, so don't expect a pec deck to "target the inner chest" in any special way.

Where it fits in a workout

Put it after your main presses. A review of exercise order research found that doing a single-joint exercise like the pec deck fly before the bench press, the old pre-exhaust idea, doesn't seem to increase chest recruitment during the press, and the exercise you do first in a session tends to get the most reps and the best strength gains (Simão et al., 2012, Sports Med). So press first while you're fresh, then use the fly machine to finish the chest with lighter, controlled work.

A simple structure that works for most people:

• Beginners: 2 to 3 sets of 12 to 15 reps, once or twice a week, after a chest press machine or bench press.
• Intermediate lifters: 3 to 4 sets of 10 to 15 reps, with the last set taken close to failure. A one second pause at the squeeze makes moderate weights feel heavy.

How much weight should you use?

Less than your ego wants. The fly is a long lever exercise, so a weight that feels light for the first few reps gets hard quickly, and the shoulder joint is most vulnerable at the stretched end of the movement. Pick a load you can control for 12 to 15 reps with a full pause at the front. If you can't hold the squeeze for a second, or your back leaves the pad, it's too heavy.

Stack numbers also aren't comparable between machines. A gym pec deck, a home multi gym and a cable crossover all use different lever arms and pulley ratios, so 30kg on one can feel nothing like 30kg on another. Track your progress on the same machine and ignore what the person before you used.

Common mistakes

Seat too low. This is the big one. With your elbows above shoulder height the movement loads the front of the shoulder capsule, and that's where most fly-related shoulder pain comes from.

Starting too wide. Setting the arms right back gives a dramatic stretch and very little extra benefit. Start with the hands roughly in line with your chest and only add range once you're comfortable.

Turning it into a press. If your elbows bend and straighten during the rep, you're pressing, and the triceps start taking the load. Fix the elbow angle and move only at the shoulder.

Shoulders rolling forward at the finish. Chasing an extra few centimetres at the squeeze by hunching forward shifts the work to the front delts. Keep your shoulder blades back on the pad and stop when the handles meet.

Bouncing the stack. Letting the plates clang between reps takes tension off the chest at the point where it should be working hardest. Control the return and keep the stack a few centimetres off the rest.

Chest fly machines for a home gym

Very few home buyers should get a standalone chest fly machine. Commercial pec fly units are big, heavy and usually priced well into four figures, and they only do one or two exercises. You get the same movement for less from one of two kinds of machine.

Multi gyms with a pec deck station

Most selectorised home multi gyms combine a chest press with a pec deck, so the same arms switch between pressing and flying. You also get a lat pulldown, low row and usually a leg station, which makes them good value per exercise. The trade-off is that the fly arc is fixed by the machine's pivots, and the stacks are lighter than a gym's.

From the machines we've reviewed, the HOMCOM 65kg multi gym is the cheapest selectorised option with a pec fly, at £335.99 when we checked in October 2026, on a 135cm by 103cm footprint that suits a spare room. The Strongway 72kg dual pulley multi gym adds a leg curl station for £469.95, on a 165cm by 105cm frame that stands 210cm tall, so measure your ceiling first. If you'd like more stack for pulldowns, the Strongway 100kg multigym sits around £999.

Of the three, the Strongway 72kg is the one we'd point most beginners towards, because the extra stack and leg work cost relatively little over the HOMCOM.

Check the Strongway 72kg dual pulley multi gym on Amazon

For a wider comparison, including models with Smith bars, see our best multi gym UK guide.

Cable crossovers and functional trainers

A dual pulley cable machine gives you a better chest fly than most fixed machines, because you can set the cables high, low or at chest height and change the angle each set. It also covers rows, pulldowns, face pulls, pushdowns and curls. The downsides are width (two towers take more floor space than a single-stack multi gym) and the pulley ratio, which means the stack figure is higher than the resistance you actually feel.

The GYM MASTER cable crossover is the model we rate for most home lifters, with dual adjustable pulleys, a large stack and a pull up bar in one frame. Other options, including more compact single-tower designs, are in our best cable machine UK roundup.

Check the GYM MASTER cable crossover on Amazon

Plate-loaded vs selectorised

Selectorised machines (with a pin and weight stack) are quicker to change and better for home use, since the plates are enclosed and you don't need a separate set of weight plates. Plate-loaded fly machines are rare at home; they're cheaper to build but you need Olympic plates and space to store them, and changing weight mid-set is slower. Unless you already own plenty of plates, a selectorised multi gym or cable machine is the sensible choice.

What to check before you buy

• Ceiling height. Many stack machines are around 210cm tall, and you need clearance above that for the top pulley.
• Footprint plus working space. Add at least 60cm around the frame so you can sit and move freely.
• Stack weight on pulldowns. The fly station rarely runs out first; the lat pulldown does.
• Seat and arm adjustment. A seat that adjusts in small steps makes it far easier to get the handles to mid chest, which matters more for the fly than for any other station.

If space or budget rules out a machine altogether, our pec deck alternatives cover dumbbell, band and bodyweight swaps that train the same movement. Browse the rest of our home gym equipment reviews for benches, racks and cable kit.

Recommended reads

• Pec deck: how to do it and muscles worked
• Cable fly: how to do it, variations and mistakes
• Best multi gym UK
• Best cable machine UK
• Chest exercises: the best moves for every part of your chest