I hear you.
But the thing is that there is no fundamental determinant of one’s arm slot (e.g. based on bone structure or something like that). Instead, the thing that controls the arm slot is the tilt of the shoulders and that is driven by things like the action of the glove side arm. Maybe things like balance and coordination come into play, but you would have a hard time making me believe that arm slot is genetic.[/quote]
I don’t claim to be very conversant with the issue, as all I have to cull from are my own experiences with myself, my son, and my nephew. In my case, my dad changed me from side arm where I was comfortable and consistent, to straight over the top, which made my natural ball movement so severe that I couldn’t control it, and which I now believe led to a shoulder injury when I got older.
My son was nearly a second victim of my father’s well meaning but uninformed attempt to change a side armer into an over the topper. The very first time I took my son out to throw (at about 5 years old) I suggested he throw more over the top (as my dad had done to/for me). He was smarter than I ever could hope to be and told me up front that it didn’t feel right. I persevered, until he said his shoulder hurt when he threw like that. I told him to throw however he felt was the most comfortable, and I never tried to mess with his arm slot again. Even a bonehead like me knows pain when throwing isn’t good lol
Lastly, my nephew was an over the top guy in high school, crazy-good pitcher, had scouts looking at him, etc. After his junior year, he went in for surgery to remove a piece of bone that hung over the tendon,impinging on it and eventually causing minor tearing and inflammation. This bone spur was anatomically normal. Many people have it. But it was throwing over the top that caused the repeated tearing of the tendon in the shoulder. My nephew said the doc had told him that if he had thrown more sidearm he may never have noticed it.
Generally, while I think that anatomy plays a small role in most people’s arm slot, whether it is a little role or a large role depends on the person.
People are smart. If something hurts, they generally won’t do it (unless the reward is greater than the pain). If the way you are built makes it hurt when you throw from a high elbow-to-shoulder slot, you lower the elbow until it no longer hurts…or you quit throwing entirely…or you keep throwing as long as you are rewarded for throwing (or you break down).
But I admit that I have no empirical evidence to back up my assertions, and as such they are worth exactly as much as the nether material on which they were written.