I believe that metal bat causes a pitcher to develop off speed pitches instead of his fastball because when ur facing a kid with a metal bat then u learn to pitch toards the end off the bat instead of tryin to jam him because with a metal u can hit it off the handle and boom u got a double. the metal bats are also incredible light. Also believe that metal bats cripple hittters because they dont learn to hit the sweet part of the bat but that would be for another forum.
my bad forgot that throwing offspeed pitches also helps u keep them off balanced causing them to hit the ball the way you want them to hit it(in the air or on the ground) but when u throw it hard they can rist flick the ball opposite way or even just stick the bat out and like before they got a double.
the hand and elbow are designed to pronote(roatate inwards) after the pitch is thrown even on breaking pitches and a lot of young pitchers dont learn to do that and causes little league elbow and shoulder problems. also curvesballs and such just aren’t good for young kids because there not developed enough to use them and they have to remember that a good fastball and solid changeup can get almost anyone out at there level(even at a highschool level)
I think the worst mistake a highschool coach can make is to force his pitcher to throw a breaking pitch