I recently received the following e-mail from a reader...
Hi, I was wondering if you can do an analysis of
Brandon McCarthy while he was with the White Sox (No arm
pain, throwing 95) and Brandon McCarthy with the Rangers
(Lots of DL time, throwing 89). I realize that the pictures
(from Dallas Morning News blog) are at different times in
his delivery, but they are different none the less.
This e-mail reflects a very common misconception that
needs to be dispelled if we are to make progress in driving down
pitching injury rates.
The assumption that people make is that pitchers
experience injury problems when their pitching mechanics change. As a
result, they assume that the way
to resolve a pitcher's injury problems is to get them back to the
pitching mechanics that
made them successful.
In my experience, altered pitching mechanics generally cause control problems
more often than they cause injury problems. The injury problems that pitchers
experience are generally a result of their pitching mechanics
staying the same rather than their pitching mechanics changing.
In other words,
those pitchers had questionable pitching mechanics to begin with, and it
is those questionable pitching mechanics that are causing their injury
I have made this point before regarding
the persistence of Mark Prior's injury problems, and the same principle holds
for Brandon McCarthy. Basically, Brandon McCarthy's pitching mechanics
have always been questionable, and his questionable
pitching mechanics are now starting to take their toll on his arm.
The thing to notice in the above photo of Brandon McCarthy
while he was with the White Sox is his significant
Inverted W. By taking his
elbows above and behind his shoulders as he does, he creates a
timing problem. This increases the load on his elbow and
shoulder and will gradually wear them down.
If you look are more recent photos of Brandon McCarthy, you
can see that the Inverted W is still there (and might even be a
bit worse). As a result, it's not surprising that Brandon
McCarthy is experiencing arm problems.
What is a bit surprising
is that he lasted this long.
The way to think of what's going on in Brandon
McCarthy's arm is as a fatigue
problem. If you take a piece of soft metal (e.g. a
straightened-out paper clip) and bend it back and forth
repeatedly, it's not going to break the first time you bend it.
Instead, it's going to handle the bending for maybe ten or every
twenty cycles. However, it is gradually going to degrade to the
point where it eventually breaks.
The same thing happens to a pitcher's elbow and
shoulder when they do something problematic like making the
Inverted W or the
Inverted L. They are
going to be just fine for a while, and might even throw a bit
harder than they normally would. However, the fact is that you
are putting an excessive load on their arm. As a result, at some
point their arm is going to break down.
Once that happens, the only way to really fix the
problem is to change their pitching mechanics so that they stop
overloading their arm. If, as with
Chris Carpenter, you only address the symptoms and not the
root cause of the problem, then the problems will crop up again.