MLB Pitching Motion: Starting the Windup

Maybe I am missing it, but it seems to me the start of a pitching windup simply lifts the glove over the pitcher’s head only to return to a resting position about chest high with the throwing arm about parallel to the ground for a moment just before the pitcher puts his whole body into the seemingly productive part of the windup that propels the baseball towards the plate.

My question is: Does the starting motion, raising the glove only to restore it about “letters high” (i.e., chest high and throwing arm parallel to the ground) have any purpose? I can’t see where any momentum is gained by this part of the windup.

Do you have a video clip to show what you are talking about? Windups vary among pitchers. Are you talking about a stretch, a simpler form of windup when there are runners on base?