seiyafan said:I tried butterfly on a free motion machine, could do 6-8 reps with 25% BWI felt a lot stress on my bicep tendon, especially the moment right after the pull, after that it gets a bit better, when both my arms are at horizontal (I actually don't feel much stress on bicep as before), so butterfly pull is really an advanced skill. I didn't feel much on the shoulders, not much on lats either because it is bottle necked by the weak bicep tendon.
Try it with a 10 second pull. That will really let you know more than doing reps.
Caution: try this with a lower weight first, don't hurt yourself. You may very well discover that you don't actually know how the activation should work. It took me a while to really get that down, but when you do it's very lat intensive whether or not you feel it in the biceps.