[quote=“Chris O’Leary”]My theory is that letting the GS elbow drift open too soon can cause both power and (possibly as a result) injury problems.
One thing that strikes me about the photo below of Mulder is how adducted his PAS upper arm is. Look at how far behind his back his PAS elbow is. Yes, it’s below his shoulders, but it’s still way behind his back.[/quote]I suggest that people should do some research on “scapula loading” before concluding that, because the elbow is “behind the back”, there is a problem. The humerus is connected to the body via the scapular complex, which includes the shoulder socket. The scapular complex can move quite freely around the rib cage, carrying the humerus with it. Thus, the humerus can be “behind the back”, as shown in the photo(s) but it can also be very “safely” aligned in the glenoid.
Go to setpro.com and see if you can find some discussion about the differences between scapula loading and hyperflexion. Let’s not automatically conclude from such still images that there is a problem. This motion can and does happen without the acromial line changing at all. The shoulder does not necessarily have to open because of the elbow “going behind the back”. There is no “cause and effect” there.
Also, the position of the glove side elbow and it’s adduction doesn’t again “cause” a problem. MLB pitchers throughout the history of the game have had varying lead arm actions with varying degrees of success.
Let’s be very careful to say “this causes that” problem, so don’t do it. As far as injury risk is concerned, all of the mechanical “causes” that we keep hearing about on this board is SPECULATION at best. Injury incidences are so prevalent in this motion, with every kind of mechanics you could discuss (with the possible but dubious exception of Mike Marshall’s) having “caused” the problem.
This is a NASTY activity on the elbow and shoulder. We’re pushing the envelope here and the risk is high. ASMI will tell you that they have absolutely no evidence of any mechanics issue CAUSING injury risk to rise. Their research indicates that it is the volume and frequency of this stressful act that is linked to injury risk, not mechanics.
That being said, it doesn’t mean that mechanics don’t play a role, just that the evidence isn’t there, yet.