JJsqueeze
Dad, Husband....legend
Getting palm to the sky is getting fully loaded before you immediately start internally rotating into release. In essence, the hand and arm are fully externally rotated to palm to the sky and then immediately start the arm whip in which the arm rotates into release. I'm convinced that the more open the hand is at 9:00 the more spin and velocity will be added to the pitch.
Do this experiment. Hold out your arm so the palm is up and rotate it fast so the palm is down. Now do the same drill but have your palm facing the wall and than rotate the hand fast so it's now down. Which drill creates a rotation that engages both the shoulder and elbow rotation simultaneously? If you said the 1st one you would be correct. BM argues this is the fastest action in the body. Why not use it to its maximum effect.
agreed, but why is palm to sky at 9 such a critical point? Why not palm to sky at 8? Or 7:30? As you said, the I/R of the forearm is really, really fast so why do you need to be loaded so early? I think there is wiggle room on the timing of the full load as long as they can load fully.
Watch for it in all the slo mo clips. You'll see what I am talking about. Many great pitchers have a little mini I/R move around 10 or 9 that takes the hand more to third, Then they E/R to palm up more at 8 ish, then they fire.