Your son is sharing an experience that’s echoed across every playing field in the country. And your concern is well warranted from first, a health standpoint, then second – a performance standpoint…
From a health standpoint, your son’s coach should be stressing the basic “prep” issues that are associated with young pitchers and their susceptibility to stress loads on the youngster’s frame that’s still engaged in the cycle of growth and development. A conditioning list of diet, sleep, shower/bath routines, simple floor exercises at home/gym, an so on should be sent home with your son in notebook form –DAY ONE. Pitching style and mechanic issues follows long after these foundation(s) are poured to give your son – and others, something solid to work off of.
From a performance standpoint, performance is usually associated with a certain level of talent, either self endowed or groomed by summer camps, private coaching and/or any combination in between. Unfortunately, in your son’s case, there seems to be a disregard for your son’s training history and all those imprints that accompanied your son up to this point. Now wonder the young man is confused. This “one-size-fits-all” mentality accompanies most first year coaches, those filling in with little position specific experience, and those that just take a second job for the $$. The worse case coaching scenario is those that are just marking time –for one reason or another.
Now here’s the tough part dad – that’s life. I know this is not up to par with the other fine advice you’ve received thus far, but it’s advice that has to be addressed sooner or later by both you and your son. This coach, regardless of his station in life, is nevertheless in the driver’s seat and his decision process will either tag your son as a “team player” or as a “fifth wheel”. The bottom line here is to do your best to encourage your son to do the best he can during show-n tell with this coach … get along by going along. Heck, he’s only 12 and he’s got a lot of playing years ahead of him. Your son will pass this experience quickly and as he transitions into the higher levels of the game – he’ll find better resources to compliment his skills.
The folks on this site are some of the best people you could possibly field suggestions from. In that regard, your questions relating to form, posture disciplines, health and related performance issues will generate tons of success by having both you and your son sit side-by-side at the monitor and read the responses together – then, hash them over.