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Sunday
Jul122009

Searching for a way to predict injuries

Two recent articles have touched on the concept of injury prediction. When someone cares enough to argue about it, the argument is usually about whether or not it is even possible to predict injury. The argument can be pretty involved, but I believe it's mostly a matter of perspective.

A few days ago, Michael S. Schmidt of The New York Times wrote an article about Stan Conte's injury prediction efforts. Conte is the director of medical services and head trainer for the Los Angeles Dodgers, and he has been working on "a formula that will give teams a competitive advantage and help them avoid players who spend their days in the training room and not on the field." Conte's hands-on experience with players, both before and after their injuries, has given him a uniquely advanced perspective on the matter.

The fact that Conte seems to believe that there is some kind of unified equation for injury prediction leaves me scratching my head. Perhaps something was lost in the translation from Conte's brain to Schmidt's article.

A quote from Conte himself later in the article seems to over-simplify his own research:

"We did a risk analysis — I can't tell you what it was, but we saw [Scott Proctor] go 83, 83 in appearances two years in a row and had some concerns," Conte said. "Without getting into specifics, we ended up not tendering him a contract."

While Conte hints at a more in-depth analysis behind the decision, the article barely hints at any variables beyond appearances. Without knowing more, it would be foolish to critique Conte's methods. There is clearly merit to his research.

A similar article popped up three days later authored by Mason Levinson at Bloomberg.com that discusses preseason shoulder strength as a key factor in determining pitcher injuries. The focus of the article is a study that links poor rotator cuff strength to an increased likelihood of injury.

Levinson mentions Conte's work and quotes Conte as saying that he has identified 80 variables that may contribute to injuries. Conte also acknowledges that, of those 80 variables, "five or six represent about 90 percent" of the equation.

In reference to the study, which he had not fully reviewed, Conte said the following:

If strength, which is one of our (80) variables, is a high predictor, then you have to put it as one of those important variables.

He seems to be saying that strength is only represented by a single variable among his 80. I sincerely hope that Conte is merely being coy. A single strength variable seems minimalist at best and absurd at worst. Perhaps it can be assumed that Conte is referring specifically to rotator cuff strength, I have no idea.

Essentially, the study confirms the presumed hypothesis that a pitcher with a weak rotator cuff - specifically the decelerator muscles: supraspinatus, infraspinatus, and teres minor - is more likely to suffer a "throwing related injury" that requires surgery.

My initial response to this idea was, "Duh," and the more I think about it, the more I think that "Duh" is the correct response.

Rotator cuff strength is a rough measure of the muscle group's fitness. So poor strength equates fairly well with poor fitness. Poor rotator cuff fitness, by its very definition, means that the rotator cuff is not fit to handle the load it is given.

The rotator cuff is an immensely important muscle group for pitching since it handles the deceleration of the humerus. Pitching with an unfit rotator cuff is a lot like running with a weak hip. Something in the chain is going to give.

A Major League Baseball trainer shouldn't need a fancy equation to tell him this.

Reader Comments (2)

The muscles of the rot cuff DO NOT exist in isolation, they are a part of a kinetic chain. Someone could have "strong" cuff, but weakness in other parts of chain that lead to greater stress on cuff than normal when they perform the act of pitching

August 11, 2009 at 8:37 PM | Unregistered Commenterbaseballprof

I don't believe you understand how the kinetic chain really works. Let's apply your comment to a very simple example: a bench press. This is an open-chain exercise.

For simplicity's sake, let's talk about weakness in the triceps. The triceps is definitely part of the kinetic chain used in a bench press. If this muscle is weak, say after a certain number of reps or because of a contusion, what happens? Do the other muscles face added stress or does the kinetic chain simply weaken?

The answer should be obvious. The muscles are under the same stress as they were during the very first rep, but now, the triceps is too weak to continue. Instead of being able to complete the rep, the kinetic energy created by the chain fails to lift the weight.

This is perfectly analogous to pitching - a repetitive exercise in which the stress levels are roughly the same repetition after repetition (not accounting for pitch types). When a single muscle or group in the chain weakens, the entire chain weakens.

This is why the study looked at all throwing-related surgeries instead of just shoulder injuries. A weak rotator cuff could conceivably cause elbow trouble because the kinetic chain has become weaker as a whole and is no longer efficiently decelerating the arm.

I think you may have also misunderstood the point of this article. This article is not an argument that super strong rotator cuffs prevent all pitching injuries. Not even close.

This article argues that a weak rotator cuff is obviously a giant red flag for throwing-related injuries and that a study was not necessary to prove it.

August 12, 2009 at 1:16 PM | Registered CommenterTrip Somers

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