Pitching Mechanics Analysis
Chris Carpenter

1/21/2008
Updated 8/3/2008

When he's healthy, Chris Carpenter is one of the best pitchers out there.
     The problem is that Chris Carpenter has a problem staying healthy.
     While some people would chalk this up to bad luck, I think a lot of it has to do with Chris Carpenter's mechanics, which are quite different from the pitching mechanics of healthier pitchers like Greg Maddux and Roger Clemens. Let me explain why I say that.

Arm Action And Timing

A pitcher's arm action and timing are the primary determinants of the long-term health of their arm, so it's always the first thing I look at.

Chris Carpenter

Chris Carpenter's problem is that, like BJ Ryan and to a lesser degree Kerry Wood, he has a major Inverted L in his arm action. This hurts his timing and is the root cause of both his shoulder and elbow problems.

Chris Carpenter's Inverted L

You can see Chris Carpenter's Inverted L at Frame 24 of the clip above. The thing to notice is how his Pitching Arm Side (PAS) elbow is at the level of his shoulders and his PAS forearm is hanging down vertically beneath it. This will increase the distance over which, and the force with which, Chris Carpenter's PAS upper arm will externally rotate, which will put significant stress on both his elbow and ultimately his shoulder.

Chris Carpenter - 2008 Update

I managed to get some 60FPS video of Chris Carpenter's start on Wednesday against the Braves. The good news is that not much has changed. However, the bad news is that not much has changed.

Chris Carpenter

Chris Carpenter's pitching mechanics are pretty much exactly what they were before his recent Tommy John surgery. That means that he's still got some Inverted L in his arm action (see Frame 37) which creates a timing problem (see Frame 43) which increases the load on both his elbow and shoulder. As a result, I wouldn't be surprised to hear that Chris Carpenter is having shoulder problems in the next couple of years.

Overall Pitching Mechanics

Now that I've given you an overview of Chris Carpenter's arm action, let me get into the details of his overall pitching mechanics. 

Chris Carpenter

I'll do this using some individual frames from the clip above.

Chris Carpenter does a good job of getting hips moving sideways toward the target early. Notice that, as he breaks his hands, his hips have moved well toward the target.

Chris Carpenter's arm action starts out being quite similar to Greg Maddux's. Like Greg Maddux, after breaking his hands Chris Carpenter drops his PAS hand to his PAS hip. However, what Chris Carpenter does after this is very different, and IMO that difference explains his different fate compared to Greg Maddux.

In order to get his PAS forearm up into the high cocked position, Chris Carpenter first picks up his PAS elbow. This is in contrast to Greg Maddux who keeps his PAS elbow at roughly the same height as he gets his PAS forearm up into the high cocked position.

As a result, by Frame 24 Chris Carpenter is in the Inverted L position with his PAS elbow at the level of his shoulders and his PAS forearm hanging down vertically beneath it. The problem is that in order to get his PAS forearm up into the vertical, high cocked position, he will have to very rapidly (and much quicker and later than Greg Maddux) externally rotate his PAS upper arm. This late external rotation will increase the level of stress on both his elbow and his shoulder.

In Frame 28, Chris Carpenter's PAS forearm has just passed through the horizontal. Notice how high his PAS elbow is at this point. It's at, if not slightly above, the level of his shoulders. This makes him vulnerable to an impingement injury to his rotator cuff.
     Chris Carpenter's timing also seems to be slightly off.
     Rather than rotating when his PAS forearm is vertical and in the high-cocked position, Chris Carpenter's shoulders appear to start rotating when his PAS forearm is horizontal, which will increase the force with which his PAS upper arm will externally rotate.

In Frame 30, Chris Carpenter is in the high cocked position, and looks quite like Greg Maddux's (although Chris Carpenter's PAS elbow is still much higher than Greg Maddux's is at this point). However, Chris Carpenter reached this point very differently than did Greg Maddux, and I believe that difference explains why Chris Carpenter has had so many more arm problems than has Greg Maddux.