If you've ever played competitive baseball or fastpitch softball, then you know that the mechanics of the swing need to be constantly tuned and improved. Case in point, let's assume you or your child are making the move out of the city rec leagues into a more competive atmosphere such as the North Oakland Baseball Federation. Going from a more "little-league" feel where the pitchers are tossing meatballs straight down the middle at 45-50 mph to a more structured and competitive league where all of sudden the kids are a bit taller and stronger and most are consistently firing fastballs at 70 mph.