Machine Chest Fly: How To Do, Muscle Worked, Benefits

Have you ever wondered how the machine chest fly can help maximize your chest muscle growth? It’s not just about using a machine to target your chest muscles, but the science behind the exercise that makes all the difference.

The machine Pec Deck fly works by creating tension on your chest muscles, which causes them to contract and grow. But did you know that how you do the exercise can also affect the muscle groups you’re working?

In this article, we’ll explore the following:

  • What is Machine Chest Fly
  • Muscle Worked During Machine Pec Dec Fly
  • How To Do It Properly
  • Its Benefits
  • Machine Chest Fly Alternates

What is the Machine Chest Fly?

The machine chest fly is a strength training exercise that works the chest muscles. It is a popular exercise in gyms and fitness centers because it isolates the chest muscles. This means that the exercise only works the chest muscles without actively working the triceps or shoulders.

This exercise provides a smooth and controlled movement, resulting in a more focused and intense workout. It is used in strength training and bodybuilding routines to build bigger and stronger chest.

It is performed using a machine that has two handles attached to a weight stack. The handles are at chest height, and the user sits with their back against a cushion while pushing the handles together in front of them. The movement is like hugging a big tree.

Then, you slowly return to the starting position, maintaining tension in your chest throughout the entire range of motion.

How Does The Machine Chest Fly Work?

When you push the handles together, the chest muscles are contracted, and the weight of the machine provides resistance. This creates micro-tears in the muscle fibers, which then repair and grow during rest periods, resulting in muscle hypertrophy.

The angle at which you perform the machine chest fly can impact the muscles that are targeted, such as the upper, middle, and lower chest.

How Does The Machine Chest Fly Work


Changing your hand position during the machine chest fly can change the range of motion. Please be careful not to exceed your comfortable range, especially if you have any pre-existing shoulder or chest issues.

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Machine Chest Fly vs. Pec Deck Fly

Both the chest fly machine and the pec deck primarily focus on the chest. They are effective exercises to build a bigger and stronger chest. But there are a few differences between the chest fly machine and the pec deck

Machine Chest Fly

  • The machine chest fly is performed using straight elbows. At the open position, it allows for greater stretch, which can lead to enhanced muscle growth.
  • It offers a greater range of motion at the open position than the pec deck.

Pec Deck Fly

  • The pec deck machine provides a greater range of motion in the finished, pads closed position. This makes the elbows closer together, which makes the inner chest muscles work harder.
  • Pec decks can be used with heavier loads than chest fly machines. This can be helpful for increasing strength and challenging the muscles further.
Machine Chest Fly vs. Pec Deck Fly

Machine Chest Fly Muscle Worked

The machine chest flys primarily muscle worked are pectoralis major muscles, including:

In addition to its target, the main pec muscle. The pec deck fly has the involvement of several synergist muscles, these muscles include,

A handful of other muscles worked or play the role of stabilizer muscles, including your

Machine Chest Fly Muscle Worked

How To Do Machine Pec Deck Fly

  1. Adjust the seat so that your feet are flat on the floor.
  2. Ensure that the handles are at chest level or slightly below.
  3. Seat Position: Sit on the machine with your back firmly against the backrest.
  4. Grab the vertical handles with elbows slightly bent.
  5. Keep your chest lifted, shoulders down and back, and core engaged.
  6. Exhale as you slowly bring the handles together in front of your chest.
  7. Once the handles are together, pause briefly at the fully contracted position. Squeeze your chest muscles and feel the tension in the target area.
  8. Inhale and gradually release the handles, allowing your arms to return to the initial position.
  9. Repeat: Complete the desired number of repetitions.

Tips For Proper Foam

  • Keep your back against the backrest. Avoid slouching or arching your back.
  • Keep your core engaged by drawing your belly button in towards your spine. This helps you keep your body stable and straight.
  • Avoid shrugging your shoulder muscles because this can make it hard for the chest muscles to work properly.
  • Focus on a controlled and deliberate movement. Avoid swinging or using momentum to bring the handles together.
  • Breathe properly, exhale as you bring the handles together, and inhale as you lower them back down. Keep breathing slowly and steadily.
  • Focus on the muscles you are targeting, specifically the chest muscles. Create a mind-muscle connection.
  • Pick a weight that you can control, that’s not too light or too heavy — find what’s right for you.
  • Your upper arms should be parallel to the floor.
  • Keep your eyes straight ahead while performing the exercise.
  • Try to bring the handles together so that your hands meet your chest. Squeeze your chest muscles to maximize the engagement.
Read More To Know More: Chest Dumbbell Fly: Muscle Worked, Foam, Alternative

Pec Deck Fly

This exercise is performed with a pec deck machine, which consists of two padded lever arms or handles that you push together in front of your chest.

The pec deck fly is especially effective at targeting the inner chest muscles. The fixed path of motion and the ability to bring the handles close together allow for a strong contraction.

Pec Deck Fly

How To Do Pec Deck Fly

  1. Set the seat height so that the handles are at chest level.
  2. Sit on the machine with your back against the backrest.
  3. Position your forearms on the padded lever arms or handles.
  4. Your arms are parallel to the floor and your elbows are bent at a 90-degree angle.
  5. Exhale and push the handles together in front of your chest.
  6. Pause briefly at the fully contracted position, feeling the tension in the chest muscles.
  7. Inhale and slowly release the handles back to the starting position.

Benefits of the Pec Deck Chest Fly

Here are some of the benefits of the machine chest fly:

1. Muscle Hypertrophy

Muscular hypertrophy is one of the primary benefits of the machine fly. When you do the exercise, it makes your chest muscles work harder, which makes them get bigger and stronger.

Over time, this can make muscles bigger and stronger.

2. Isolation of Chest Muscles

The machine chest fly is an isolation exercise, meaning that it targets the chest muscles specifically. This is good for people who want to build their chest muscles without using other muscles like the shoulders and triceps.

3. Enhanced Range of Motion

The Pec Deck Chest Fly provides a controlled and guided range of motion compared to other chest exercises, such as dumbbell flys.

The machine’s design allows for a full stretch and contraction of the chest muscles, ensuring optimal muscle activation.

4. Reduced Joint Strain

Compared to barbell bench presses or push-ups, the Pec Deck Chest Fly minimizes the strain on the joints, particularly the shoulder joints.

This makes it a good choice for people who have shoulder issues or who want to reduce joint stress while still working their chest muscles.

5. Helps With Posture

By strengthening the chest muscles, machine chest fly can also help to improve posture, which is important for overall health and wellness.

6. Chest Opener

The fly is great because it’s a nice chest opener which teaches scapular retraction.

Scapular retraction basically means the ability to pinch your shoulder blades together-an action that’s super important for combating poor posture.

Alternatives to the Machine Chest Fly

If you do not possess a machine fly or are seeking alternative exercises to target your chest muscles, the following exercises are worth considering:

1. Push-Ups

Push-ups are a great bodyweight exercise that targets the chest muscles. They can be performed anywhere and require no equipment.

2. Dumbbell Chest Fly

The Dumbbell fly exercise mimics the motion of the machine chest fly and targets the chest muscles effectively.

3. Cable Chest Fly

The cable chest fly is a similar exercise to the machine chest fly but uses cable instead of a pec deck machine.

Performing this exercise with cables instead of machine fly allows for constant tension, which helps build Chest fibers.

4. Cable Crossover

The cable crossover is another chest-focused workout that can be done with a cable machine.

Cable provides constant resistance and helps develop the lower and the central chest muscles by providing the much-needed stress in the lower and the inner pecs.

Machine Chest Fly vs. Dumbbell Fly

The machine chest fly and dumbbell fly are both effective exercises for targeting the chest muscles, but they have some key differences.

Machine Chest Fly

  • The machine chest fly is a guided movement that provides a consistent resistance throughout the entire range of motion.
  • It is a great exercise for beginners or those with limited mobility.
  • The pec deck fly might not employ as many stabilizing muscles as the dumbbell fly.
  • Some people may find the machine chest fly to be less enjoyable or less versatile than other chest exercises.

Dumbbell Chest Fly

  • The dumbbell fly is a popular exercise among bodybuilders and fitness enthusiasts.
  • It allows for a greater range of motion and engages more stabilizer muscles than the machine fly. This can result in greater muscle activation and strength gains.
  • For those with limited mobility or shoulder issues, the dumbbell fly may be more challenging to perform with proper form.
  • Additionally, using heavy weights during the dumbbell fly can increase the risk of injury if not performed correctly.


Is the fly machine good for chest?

The chest fly machine is a good exercise for people who are new to lifting or experienced lifters. It helps them do the right movements and doesn’t use too much of their core muscles, which helps them work their pectoral muscles.

Like all flyes, the pec deck fly is a great exercise to add variety into your chest workouts and challenge the muscles in a unique way.  

Do chest flys build size?

Yes, doing chest exercises helps make the chest muscles bigger. When performed properly and with appropriate weight or resistance, chest fly exercises can create micro-tears in the muscle fibers, which stimulate muscle growth and hypertrophy.

How many sets and repetitions should I do for machine chest fly?

Do 3-4 sets of 8-12 reps of machine chest fly. Adjust the weight, reps, and sets to further challenge yourself while still maintaining proper form.


The machine chest fly is a beneficial exercise for enhancing the development of the chest muscles. During pec deck fly, small tears in the muscle fibers are created. These micro-tears then repair and grow during rest periods, resulting in muscle hypertrophy.

If you can’t do the pec deck chest fly, there are a few other exercises you can do to work your chest muscles.


  • Solstad TE, Andersen V, Shaw M, Hoel EM, Vonheim A, Saeterbakken AH. A Comparison of Muscle Activation between Barbell Bench Press and Dumbbell Flyes in Resistance-Trained Males. J Sports Sci Med. 2020 Nov 19;19(4):645-651. PMID: 33239937; PMCID: PMC7675616.
  • Borges, Eduardo & Mezêncio, Bruno & Pinho, João & Soncin, Rafael & Barbosa, João & Araujo, Felipe & Gianola, Fabio & Amadio, Alberto & Serrao, Julio. (2018). Resistance training acute session: pectoralis major, latissimus dorsi and triceps brachii electromyographic activity. Journal of Physical Education and Sport. 18. 10.7752/jpes.2018.02095.
  • American Council on Fitness. Three most effective chest exercises.

Bodyweight Chest and Shoulder Exercises To Build Mass

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