The Root Cause of Mark Prior's Shoulder Problems?

Those of you who are familiar the analyses I have done of the pitching motions and mechanics of a number of professional pitchers know that I am not a fan of Mark Prior’s motion and mechanics.

I think they have contributed to his injury problems.

Just today I learned that Mark Prior is reported to be experiencing problems with his shoulder. Based on an analysis of his motion that I did of his motion back in December of 2005, this is something that I predicted would happen.

I believe that the problem is that, as he turns his pitching arm side forearm over, he bring his elbows both behind, and more importantly above, his shoulders. In the analyses I have done, I believe I have noticed a pattern of shoulder injuries in pitchers who do this.

Why does it seem like every statement you make is a pure conejcture?
On your site it says "I am not exactly certain what the exact mechanism of injury is, but I believe it might be related to the impingement of the muscles of the rotator cuff on the bony structure of the shoulder. " Again, another guess with no medical or scientific evidence to back it up, just what YOU think.


The pattern is that pitchers who take their elbows above and behind their shoulders seem to experience more shoulder problems. The scientific and medical evidence is a problem called “impingement syndrome” in which the muscles and tendons of the shoulder come into contact with the bony structures of the shoulder. This is believed to compromise the musculature of the Rotator Cuff.

Mark Prior’s motion is very different than Tom Glavine’s. In the photo above that you posted, notice that Glavine’s elbows are at the level of his shoulders, not above them. I believe this explain Glavine’s lack of significant shoulder problems.

In the picture of Glavine, it looks to me that his elbows are about 4 to 5 inches above (or higher than) his shoulders. To put it in better perspective, his glove side elbow looks to be at eye level, meaning it must be several inches higher than the shoulder. Am I seeing something no one else is?

You are correct. Now, like a broken record, where does this still image fit in the overall motion? I caution, once again, that we don’t draw conclusions based on this alone. It is helpful to analyze one point in time but to really get the whole story, you need video.

His glove-side elbow is definitely at eye level and several inches above his shoulders. However, his pitching-arm-side elbow (which is what really matters when it comes to rotator cuff problems) is at most 1 inch above the level of his shoulders.

Based on the analyses I have done, I believe that pitchers start to run into problems when they move their elbows more than a couple of inches above their shoulders. That puts Glavine on the borderline.

One things to keep in mind is that Glavine currently keeps his elbows lower than he did when he was pitching in Atlanta. This may be related to reports of shoulder problems I have heard that he had while pitching in Atlanta. He may have had to ensure that he keeps his elbows low to fix that problem.

Chris, got some other pitchers other than Mark Prior to back this theory up?

  1. Don Drysdale

  2. Bobby Madritsch

  3. Billy Wagner

  4. Paul Byrd

  5. Kerry Wood

By way of comparison, Nolan Ryan (among others) did not do this…

  1. Nolan Ryan