Again, high elbow when? Did you understand what I said about the timing of the elbow dropping relative to the range of external rotation? Also, how does Chris know what really caused their problems? Could be many things. I propose it's because external rotation to the extremes, and at high velocities, is just plain nasty!!! Add conditioning differences and genetics and who knows what it is.
All speculation. What about the injured pitchers who do not do what Chris is speaking of?
Look at it this way. High level, hard throwing pitchers have the humerus go into extreme ranges of external rotation, to the point where the connective tissues are stretched to their limits, regardless of what mechanic got them there. At their limits. It stretches them and they rebound. That's the transfer mechanism of the energy that was generated up until that point. This stretch and rebound is in all of them. Not just the inverted W's, L's, slingers, etc. All of them.
It's just plain nasty business we're dealing with here.
Now, I happen to "believe" (not know, believe) that the M or inverted W may just be harder on those tissues. I said it several years ago on this forum, in discussions on this with Chris, that the violence of the external rotation in this mechanic may cause that stretch and rebound to be more damaging. Chris agrees with me on this but he still talks about the elbow height, which, as I noted in my previous post, isn't what he says it is. That's what I don't get with him. The elbow doesn't stay up there through any extreme range of external rotation of the humerus.