It’s commonly believed that young pitchers who throw “all arm” are stressing their arms more than pitchers who put the whole body into it, whose arms are “just along for the ride”. I’m inclined to take the opposite position.
My son (age 9) is currently recovering from “Little League Shoulder” (shoulder growth plate injury). He is about to start a rehab program that will include some video for the physical therapist to check his mechanics. My ortho doc, who has never seen him throw, suggested that part of the problem could be that he is throwing too much with his arm, and ought to be putting his whole body into the effort.
The only thing is… compared to kid pitchers his age that I’ve seen, he puts his whole body into it very well. His arm really is “just along for the ride”… (but what a rough ride it has been)
This has led me to think that the real high stresses on the joints of a young (or old!) arm are the “dynamic” forces – forces that are in reaction to the motion and intertia of the arm itself, rather than the “static” forces – the forces that the contractions of the muscles of the arm exert on the joints. I think that a lot of mechanics gurus and even top arm docs don’t have a solid understanding of solid body dynamics and they miss this point.
Furthermore, it’s logical that the heavier the ball you are throwing, the lower the arm speed, and thus the lower the dynamic forces on the joint. So if I’m right, throwing a heavier ball would lead to fewer injuries and throwing underweight balls would lead to more injuries.
What do you think?