Pitching Mechanics - good or bad?

Question
My U12 daughter is pitching and has been pitching for 3 years.  Her pitching coach has instructed her to bring her hip threw upon the completion of the pitch.  That is, open wide (body faces 3rd bases), then upon the completion of her release, follow threw with her hip, having her step forward toward the plate.  She is very successful with this method. Last night, my other daughter抯 coach informed me that this could be damaging her shoulder and that she should be dragging her leg, not stepping threw.  Is there a right or wrong way?

Answer
I don't see how closing up after release is going to damage the shoulder.  I agree with the U12 coach and like the hips to close immediately following the release.  This puts her into the correct fielding position.  It is important that the hips do not close prior, because that will cause her to throw around the hip and usually send the pitch inside on a RH batter.  I'm not a medical expert and will not say the second coach is wrong, but you might ask him to elaborate on his reasoning behind this theory.  Most of your big time pitchers like Finch, Hernandez, and Osterman don't take a deliberate step to close the hips, but let the natural closing of the hips following the release and completion of the drag, pull them into the correct position.  That may be what he was talking about.  I hope this helps.

Coach Mike