Playball ... I'm not advocating a preteen throwing a curve. I'm tired of people improperly stating the curve is why a kid's baseball career ended early because it's dangerous to throw. It may be dangerous to throw a curve improperly, just like any other improperly thrown pitch. With the number of TJ surgeries it appears just pitching may be hazardous to arm health. Afterall, it's an unnatural motion.
Great reply. Every study done on the subject indicates that curves (and this isn't isolated just to those people consider "correctly thrown") are not the source of arm injuries and, in fact, at least two of those studies conclude that the force behind a fastball is far more injurious to the arm of a youth pitcher. My own son has been throwing about 20% breaking pitches since he was 10 despite the fact he has always had a well above average fastball for the very reason that it gives his arm and elbow a break from the rigors of the fast ball. If a pitching instructor holds off on teaching the curve until a later age because he wants his students to master the fb and cu first, I have no problem with it. If he holds off because he's following the conventional wisdom that curve balls are bad, he may be doing the kid a disservice.
Now, I will hear quotes from Andrews (mainly the "no curves until they shave") against the curve. His own organization conducted a 10 year youth pitcher study that bagan with the premise that curves are a factor in youth pitching injuries. the surprise conclusion was that there was absolutely no coorelation between curve balls and injuries. Andrews, however, continues to preach no curves until after puberty. However, his logic and reasoning have changed. Originally his advise was based on arm damage to growth plates. His reasoning now on why teacing the curve ball early is something along the lines of some strange logic. He contends that those pitchers who learn the curve ball early in their development experience considerably more success. That success leads to those pitchers being overused at early ages, so it would be better to be mediocre at a young age so as to avoid the temptations over overuse.