Well, I've been doing that exercise for many years. It was shown to me in college by the trainer for the football team as I recall.
Anyway, I'd like to hear Ano's view of that. I suspect it's a lot like stretching in a doorway. Some guys can do it and some guys shouldn't do it.
But, I'll defer to Ano or one of the other guys with more technical knowledge of the rotator cuff.
Interesting point of view. Thanks for the input.