Alright, I was watching this video about Mike Marshalls mechanics, and saw the Pronation Curveball.
If you watch closely in the super slowmo, the pitcher Jeff Sparks throws the curveball normally with supination, but immidietly after release he turns over his hand and pronates through his finish. Is this really all there is too it? The reason the curveball can be hard on your arm is because due to the supination through the finish, a tendon in your forearm begins to lengthen and pull on a growthplate in the elbow. And pronation protects your elbow because it keeps your elbow from locking up as your arm goes through its finishing plane.
(To see and feel this, pretend you are throwing a curveball and keep your arm supinated or “turned up” throughout the finish. Does it hurt? Yes because your elbow is locking up. Now pretend to throw a pitch, but point your thumb down or pronate upon the imaginairy release. This doesn’t hurt because your arm has a full plane to slow down, and your elbow doesn’t lock)
So is this whole pitch, really, just a combination of the supination of the curve, followed by the pronation which keeps the elbow from locking up? Seems to simple…