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Why internally rotate shoulders for dumbbell fly?

Posted: Sat Dec 03, 2016 4:40 pm
by fluoresce
For the dumbbell fly and lever seated fly, ExRx says that you should internally rotate your shoulders.

Why?

I thought it was to better isolate the pectoralis major; however, according to Wikipedia's Chest Fly page, if you internally rotate your shoulders, your anterior deltoids get more involved:

"The chest fly ... primarily works the pectoralis major muscles to move the arms horizontally forward. If internally rotated, it is assisted in this by the anterior head of the deltoideus in transverse flexion. If externally rotated, the contribution of the deltoid is lessened and the pec major is strongly emphasized as the transverse adductor."

Why, then, does ExRx recommend internal rotation? Have I misunderstood or something?

Here are the ExRx exercise pages:

exrxDOTnet/WeightExercises/PectoralSternal/DBFly.html
exrxDOTnet/WeightExercises/PectoralSternal/LVSeatedFly.html

Re: Why internally rotate shoulders for dumbbell fly?

Posted: Sat Dec 03, 2016 10:07 pm
by stuward
I don't know enough about this exercise to voice an opionion, however, Wikipedia uses this page for their source: http://www.fitday.com/fitness-articles/ ... t-fly.html" onclick="window.open(this.href);return false; However, that article doesn't even mention internal or external rotation. I wouldn't place any faith in it.

Re: Why internally rotate shoulders for dumbbell fly?

Posted: Wed Dec 07, 2016 11:22 am
by fluoresce
Thanks, Stuward. :-)