When Aroldis Chapman threw the fastest pitch ever recorded-105 MPH if you haven't heard-he threw it past Tony Gwynn Jr. ("I didn't see it until the ball was behind me."). Tony Gwynn Jr.'s pop, Hall of Famer Tony Gwynn Sr., was Stephen Strasburg's coach at San Diego State. Coincidence? I'll leave that for the astrologists amongst you to decide. But Gwynn was perhaps onto something this spring when he suggested that the Nationals refrain from having Strasburg pitch at all this season. "I would be really cautious," Gwynn said, "I wouldn't want to rush it."
I wrote an article earlier this season, right about the time Strasburg began breaking down, discussing the supposed relationship between mechanics and major shoulder and elbow injuries amongst pitchers. That article drew heavily from Chris O'Leary's work and essentially argued that Strasburg exhibited three mechanical traits that seem to cause major injuries, namely that he showed signs of hyperabduction, the inverted W (or in Strasburg's case, a V), and a serious timing problem.
While the article I wrote may seem somewhat prescient, I think it would show folly on my part for me to claim any sort of authority on the subject. O'Leary's theories are still theories and there don't seem to have been any major studies based on them done yet. (On another note, I hope to present some of these studies in the very near future, so stay tuned.) What I can say, however, is that I think I understand O'Leary's ideas reasonably well and because anecdotal evidence makes me think they work pretty well-and because I get a kick out of this kind of analysis-I'm going to give you a case, as much as it pains me, as to why Chapman might end up pitching longer than our dear friend Stephen Strasburg.
First things first: Strasburg's mechanical worries. First, Stephen Strasburg exhibits hyperabduction. Hyperabduction occurs when a pitcher raises his pitching arm side (PAS) elbow above the level of his shoulders (The level of your shoulders is the imaginary plane that passes through your shoulders parallel to the ground when you are standing up straight on a level surface.) when his arm is in the "high cocked position." It seems to lead to rotator cuff and labrum injuries. As you can note in the picture below, Strasburg appears to be guilty as charged.
Strasburg has also been known to exhibit the "famous" inverted W a.k.a. the M a.k.a the most contentious point of discussion in the pitching mechanics world. The inverted W is fairly easy to spot (Look at some pitctures of Mark Prior for the Euclidean Ideal of the inverted W-my God, what a beautifully perfect W.) and it has been argued in many forums that it leads to injury problems. Strasburg can be seen exhibiting a variation of the inverted W in the above photo, namely the inverted V.
The inverted V is merely a variation on the inverted W because-and this is the crux of O'Leary's arguments as far as I can tell-they both lead to a timing problem which appears to be the cause of (or at least a strongly correlated factor with) pitcher injuries. That is, the inverted V and inverted W are not inherently bad, but they make it difficult for pitchers who practice them to get their arms into the "proper" position before pitching, the proper position being the position such that the arm is perpendicular with level plane of the ground as the toe of the lead foot hits the ground. That is, when your front foot lands, you better make sure your throwing forearm is pointing to the heavens. Below we see Strasburg failing to do get into proper position and we also see Chapman having much more success.
Now for the disclaimers: First, Strasburg shows a large variation in his mechanics-a quick glance at google images will tell you as much. Sometimes he looks much better than other times. His mechanics also seemed to vary from week to week. How can we pinpoint one set of mechanics as a causal factor in his breakdown?
Second, Chapman is just a reliever right now and these sorts of predictions seem to not work as well for relievers, probably because they pitch so infrequently. I will add here, though, that Chapman appears to refrain from both hyperabduction and any form of the inverted W.
Third, though Chapman seems to have better mechanics in many ways, his timing is not perfect either. He seems to have the the opposite problem of Strasburg, that is, while Strasburg does not bring his forearm all the way up in time, Chapman brings his arm too far and goes past the perpendicular line. I liken the process of getting into the proper position to the Japanese game show called "Human Tetris" where the competitor must contort her body into the perfect shape at exactly the right time to win, except in pitching the shape is the same every time (for a given arm slot) and the timing is exceedingly difficult to get right.
Fourth, as I mentioned before, O'Leary's theories seem to be largely based on hunches, though to me the hunches seem very good. Yet, people still have a lot of animosity toward O'Leary and his theories and I don't doubt that out of the three people who will read this article, at least one will think I'm an idiot. True, I haven't established causation but have any of the other theories behind pitcher injuries out there done the same? I've heard that Prior was overworked as a youngster and that Kerry Wood was "frail" and yet for every overworked youngster and frail pitcher there is a Mark Buehrle and a Randy Johnson (Johnson's shoulder surgery was batting-related).
It seems ridiculous to exclude mechanics from a discussion of pitcher injuries. Surely many people will accept that there are certain ways to design a car that approximates the desired tradeoff between efficiency and longevity and that improper use will wear a car down. Why is the case any different for a person's body? Of course, the problem becomes all the more complicated when we start dealing with the extreme velocities-you drive your car too fast around a turn and you wear on the suspension; worse your tires slip and you crash. Will Aroldis Chapman pull a Stephen Strasburg and roll out or will he prove to be the more reliable model? Seems hard to say but let's hope for baseball's sake that this mechanics thing gets figured out soon.