pitching

My own observations and thought process on sidearm is that it using the shoulder in a motion that it was not necessarily designed for.

I have heard several doctors advise against sidearm, as well as Bill Thurston, whose insight I value highly.

Part of the problem is that many throw sidearm incorrectly, resulting in an almost uphill throw. Thrown correctly, your hand starts level with your shoulder and continues forward and across in a downhill motion, with an arc of deceleration bringing your arm across your chest and your hand wrapping around your ribcage.

I like the sidearm delivery as a "different look", and don't think featuring it a couple of times a game is all that dangerous. I would NEVER advocate it as the primary delivery.

From a purely non-scientific point of view, two predominantly sidearm pitchers that come to mind are Todd Frohwirth and Dan Quisenberry. They enjoyed some success, but their careers had some good years initially, followed by mediocre to poor seasons later.

Quisenberry used it to stay in the majors to make up for his under 80 MPH "fastball".