the pectoralis group is not part of the rotator cuff. the rotator cuff consists of the supraspinatus, infraspinatus, subscapularis, and teres minor muscles.

Very cool, Driveline. I agree with you on most points.

Like you, I'm not big on leading with the elbows and I like alot of what Chris O'Leary says, however, I don't believe the inverted W in and of itself is bad. The end results of the inverted W, bad timing (in alot of cases) is what I think is bad. In the case of Crow, atleast in these two videos, I don't see his timing being that bad. While his arm is late at front foot strike, he goes from the inverted W to a good position with his forearm vertical and his elbow down before his shoulders rotate which is the key. The translation of force from the hips up doesn't happen until the shoulders rotate. Separation of hips and shoulders is excellent in Crow, I would guess he approaches the 18% separation that Flesig noted in elite pitchers in his paper in the Journal of biomechanics.

First a question, what do you consider "bad" about the wrist hooking that Crow exhibits? I've heard this before but I don't see it as a mechanical flaw.

Again, I don't like leading with the elbows and you are correct in assessing Crow's arm being behind the acromial plane but understanding that in a study done by the Journal of Sports Science and Medicine, even the most excessive pitchers (about 14 degrees behind) exhibit about a 7% increase in medial elbow force. Not a significant amount. In Crow's case, he has some adduction but I would not consider it excessive, and while being a mechnical flaw, I consider it minor. A "fix" but not a "disaster" is how I would view it.

Other good things I see, back foot is down and in line with the plate at release meaning he's efficient and rotating his hips well. His glove gets out in front at foot strike and stabilizes, however, IMO, he could get more. His elbow is down below the plane of the shoulders at release.

The bad. His hips open early. He's probably only at about 50% stride length when you see his front toe start to open. This does two things, first, he's not carrying his momentum into his rotation as late as he could be and because his hips open early he feels "late", which in IMO is the cause of leading with the elbow and the inverted W/bad timing. Like I said, I think he catches up later in his motion by rotating his shoulders late but there are stresses that could be alleviated there. His dynamic balance is pretty solid although he throws his head off his center of gravity just a bit and he strides. Again, a small "fix".

Overall, I'm pretty high on Crow. Mechanically I don't see him as any more of a risk than most pitchers his age. I'd spend a little time making tweaks and adjustments but wholesale changes are not necessary.