Thread by @SteveEnglishbey

My good friend[ and VERY smart!!] Rick Collins argued that the guy on the right was throwing harder.

To which Paul said: "The player on the right understands how to transfer/increase rotational momentum developed by the upper body to the arm using shoulder horizontal adduction."

https://twitter.com/setprosports/status/1439607271277875207

Now [of course] Paul knows the answer ---because he did the simulations!
But. For outside observers the question is: How can one "see" ....correctly?

He cites ---as THE determining factor as regards the difference in velocity ---"horizontal adduction" ie., the back scapula continuing to "slide" along the ribcage [I refer to this via the more proximal articulation [scapula PROTRACTION].

Now, in just LOOKING at both clips how does one KNOW that it is THIS specific muscle action that is THE causal factor in the differential in speed?

Answer: No one ---can ACTUALLY SEE-- this muscle action. Technically speaking, only via emg measurements can one ACTUALLY SEE/measure muscle action.

BUT. One certainly can INFER --based on a GOOD understanding as to "how the body works" in this relatively SPECIFIC context that "horizontal adduction" [scapula protraction] is THE causal factor in the speed differential.

How can one "see" this muscle action? Answer: By looking at the arm/trunk movement that occurs AFTER release.

That is to say that IF you look CLOSELY [and yes you have to spend some time looking over and over again at the actions post release], you can see that the throwing shoulder of the guy on the right creates a more pronounced displacement of that shoulder.

In other words that back deltoid region moves past the head [and slightly more towards 1st base] to a greater degree, relative to the guy on the left.

And here's the key to understanding this empirical fact: The ONLY way this slightly greater displacement of the back deltoid can happen is via better "connection" of the back scapula retraction from lag to release.

What does "connection" in this context actually mean one might ask? Well, what it means is that the force/momentum developed by the hips and mid -thoracic is optimally transferred via the last proximal link of the hips/trunk----scapula protraction.

In the clip on the left one can infer [again if one REALLY KNOWS what to look for] that this last proximal link [scapula retraction] is somehow inhibited, ie., it slows/stops.

And it is this slowing/stopping that indeed is the causal difference in velocity.

Now, having tried to explain this difference in some detail, my hope is that at least SOME of you see this.

And I would add this: Years ago Paul said on his website [context was in response to some on the site NOT really seeing what he was presenting]; "People are only capable of seeing what they are capable of seeing."

Meaning of course that one's interpretation of movement dynamics is either impeded or enhanced by one's requisite understanding as to, as I say simply, "how the body works."

In this context, and as regards my understanding, I will argue that my ability to "see" has been informed by my being thoroughly absorbed in the Setpro info. AND my working with players. AND my thousands of hrs. of trying to "do it " via specific exercises I developed over 20 yrs

@threadreaderapp unroll