My question, is external rotation a result of throwing hard or does external relation produce velocity. [/quote]
my answer would be a bit of both.
high level (rotational) throwing mechanics can create more extreme shoulder external rotation than low level (linear) throwing mechanics.
However, you do need a fair amount of looseness in your shoulder to be able to achieve the kind of ROM that you see in all 95 mph throwers. My opinion, though, is that most players who have been throwing since they were kids should have built up plenty of flexibility due to the high volumes of throwing each year. The focus, in my opinion, should not be on increasing external rotation with static stretching…even if you do gain additional ROM you aren’t building strength or elasticity at that end range.
So then how do you use the flexibility that you have at the GH joint during the throw to achieve the position you see in so many MLB photos
My understanding, based off of Nyman’s work, is that you want to line up the elbow, hand and ball with the plane of rotation of the shoulders. This maximizes external rotation due to increased torque on the shoulder joint. It therefore also maximizes velocity (you’re applying force to the ball over greater ROM, AND you are creating more forceful stretch reflex in the shoulder).
This is the difference between a linear thrower pushing the ball with a labored effort and a high level thrower seemingly sling-shotting the ball with ease.
To explain my understanding of the topic a little more, I’m going to use some .gifs.
watch the plane of rotation of the shoulders and note how the elbow forearm hand and ball are all in this plane
now for an ugly clip of me from a long long while back
note the linear release and the fact that everything is not in the same plane of rotation…it’s a push throw, and even though I have the flexibility to easily get 180 degrees of ER, there was not enough torque created in this particular throw to get anywhere near that.
just think “rotate through release” rather than “finish towards home plate” or whatever other cues might have you finishing linearly.
DON’T be afraid to fall off to 1B during your follow through (3B for lefty). In fact, It’s a sign of good rotation. Just about everybody at every level of the game save Greg Maddux would do better with that extra velocity and deception than worrying about finishing towards home plate in a good fielding position