HomeExercise LibraryHow To: Pec Deck Fly (Butterfly)

How To: Pec Deck Fly (Butterfly)

Pec Deck Fly (Butterfly)

The pec deck fly, often also referred to as the butterfly exercise is an old school isolation exercise for the chest.

Regardless of how small, cramped or little equipment your commercial or hotel gym has, chances are they've got a pec deck machine!

The pec deck, utilizes an arcing movement to maintain tension on the chest and build that width.

Movement: Isolation

Targets: Chest

Required: Pec Deck Machine

Optional: N/A

Pec Deck Fly Form:

Sit on the pec deck fly machine with your back against the pad.

Grasp the pec deck handles ensuring your upper arms are parallel to the floor.

Push the handles together as you contract your chest in the middle.

Hold this contraction for 1 second.

Allow your chest to stretch out as much as possible as you slowly return the handles to the starting position, arced out by your sides.

Pec Deck Fly Variations

Unilateral Pec Deck Fly

Instead of pressing with two handles at a time you will push one handle while holding the other handle of the pec deck in a static hold, maintaining tension on that side of your chest between repetitions.
This is a fantastic core exercise and is often used for overcoming a lagging side/correcting dominance.

See also
Chin Ups For Biceps - The Often Neglected Arm Exercise For Bulging Biceps

You'll find when flying one side at a time your core will need to be engaged the whole time to maintain your position on the machine.

Common Pec Deck Fly Mistakes

Utilizing A Partial Range Of Motion

As you maintain a slight bend in your arms you must allow the pec deck to pull your arms back until you feel the stretch in your chest.

Not Maintaining A Bend In Your Arms

With dead straight arms you'll find that you're not only failing to get the same stretch and contraction in the chest, but you're also placing yourself at greater risk of elbow/shoulder injuries.

Failing To Contract The Chest On Each Repetition

At the top of the movement you must squeeze your chest muscles together in order to get a full contraction, if you're merely going through the motions but not taking the time to squeeze on each repetition you're going to fail to see the results you're after.

Similar & Substitute Exercises 

  • Cable Crossovers
  • Flat Dumbbell Flies
  • Incline Dumbbell Flies

Any Questions Regarding The Pec Deck Fly? Ask Below!

Scott J.
Scott J.
I’m SJ. I’m a fitness enthusiast and published author. I transformed my body from a skinny fat 135lbs with 18% body fat to a solid 192lbs at 8% body fat. I became qualified in a field I was passionate about. I founded several online businesses that allow me to pursue ideas and projects in my life that I am passionate about without having to constantly worry about money. I published several eBooks explaining the training and dieting techniques I used to achieve the body I have today. I learnt a plethora of new information on dieting and fitness by reading and applying what I read, to find out what does work and what doesn’t work, because as I’m sure you’ve noticed the health and fitness industry is full of non-sense claims and BS. I found out what was true and what worked for me and applied that knowledge. And you bet I had fun during the whole process.

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