# Machine fly

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{{Short description|Strength training exercise}}
A '''machine fly''', alternatively called a '''seated lever fly''' or '''"pec deck" fly''' is a [strength training](/source/strength_training) exercise based on the free weight [chest fly](/source/Fly_(exercise)). As with the chest fly, the [hand](/source/hand) and [arm](/source/arm) move through an [arc](/source/range_of_motion) while the [elbow](/source/elbow) is kept at a constant angle. Flyes are used to work the [muscle](/source/muscle)s of the [upper body](/source/Torso), primarily the sternal head of the  [pectoralis major](/source/pectoralis_major).  Because these exercises use the arms as [lever](/source/lever)s at their longest possible length, the amount of weight that can be moved is significantly less than equivalent press exercises for the same muscles (the [military press](/source/military_press) and [bench press](/source/bench_press) for the shoulder and chest respectively). Denie Walter is credited with calling it the Peck Dec back in the 1970s.{{citation needed|date=March 2022}}

==Equipment==
There are two designs of weight training machines available for this exercise. The seated lever fly machine, and the Pec Dec. The seated lever fly involves grasping two handles at shoulder height, and pushing them together while keeping the elbows at a constant angle.<ref>[http://www.exrx.net/WeightExercises/PectoralSternal/LVSeatedFly.html Lever Seated Fly] at exrx.com</ref> When using the Pec Dec machine the hands grip two handles at head height, while the forearms push against two pads at chest height.<ref>[http://www.exrx.net/WeightExercises/PectoralSternal/LVPecDeckFly.html Pec Dec fly] at exrx.com</ref> The anterior [deltoids](/source/deltoids) are used as [synergist](/source/Anatomical_terms_of_muscle)s in both variations. The [biceps brachii](/source/biceps_brachii) act as a synergist in the seated lever exercise, but not on the Pec Dec due to the raised arm position.

In some machines, the seated lever can be adjusted to perform a [rear delt fly](/source/rear_delt_raise) exercise.

<gallery mode=packed heights=200>
Butterfly-machine-2.png|Butterfly machine fly (pec deck) start
Butterfly-machine-1.png|Butterfly machine fly (pec deck) end
</gallery>

==References==
{{reflist}}

{{wiktionary|flye}}

{{Strength training exercises}}

Category:Weight training exercises

{{Bodybuilding-stub}}

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Adapted from the Wikipedia article [Machine fly](https://en.wikipedia.org/wiki/Machine_fly) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Machine_fly?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.