The conclusion here looks to blame "bad coaching" for the amount of major league UCL tears. I'm not just talking about pro players. One of my good friends plays at Michigan State and he blew his UCL this winter and is rehabbing the rest of the year. Every D1 team has at least one. High school kids and kids that haven't even hit their teens yet are being instructed to have this surgery.
"Bad coaching" at the youth level can mean so many things...
-teaching inefficient mechanics
-overuse when the pitcher has been undertrained
-long toss? (a different discussion)
-the implementation of overload/underload balls
Obviously, not just one thing is causing the amount of UCL tears around baseball.
They're finding a majority of UCL injuries in older high school kids through college seniors (17-24 years old). A kid that's still playing at 20 years old probably was doing something right when he was 12. He has a solid base of mechanics, but was he overused as a youth while being undertrained? Was he throwing 220 foot long toss and overload/underload balls too young?
The amount of things that can go wrong with bad coaching and young players is the problem. The stress that velocity means everything is absolutely correct but I feel it's being stressed too young and incomplete. If you want your 13 year old to throw 80 mph, you better be covering all bases for him to stay healthy. If he's throwing every day, he better have been trained to do so. His mechanics must be sound, he must recover well, he must train well, and he musttake care of his body away from the field well.
Just my thoughts.