Yesterday afternoon, I received an e-mail from Glenn Fleisig, Ph.D., the biomechanist whose research I discussed in the wake of his interview contribution to Sports Illustrated's piece on Stephen Strasburg's mechanics. He explained that some of what I wrote misinterpreted what he said in the SI story.

After I spoke with Fleisig on the phone today, it seems that I inaccurately characterized his work and opinion by unintentionally assigning some of the SI writer's thoughts from the piece to Fleisig.

Here is Fleisig's full letter:

I read with great disappointment Adam Kilgore's story about Stephen Strasburg (Washington Post, March 10, 2011). I was disappointed because there were several inaccuracies which can be misleading to the readers. First, it was inaccurate to say that I had a "definitive assertion" that a specific mechanical movement led to Strasburg's injury. Rather, I agree with Dr. Tim Kremchek, who is quoted as saying that it is impossible to know for sure how Strasburg's injury happened. Kilgore's story refers to two previous articles (Sports Illustrated, March 8, 2011 and Washington Post, July 27, 2010) which explained how mechanical flaws correlate with increased joint stress in pitchers in general, not in one pitcher (Strasburg) in particular. These findings are based on thousands of pitchers of all levels who have been tested in the biomechanics lab of the American Sports Medicine Institute, including hundreds of professional pitchers. Data from these tests have led to dozens of published scientific studies which have been reviewed by other scientists and shared with coaches and doctors. In publications, presentations, and interviews, ASMI explains pitching biomechanics in general but never discusses specific pitchers. ASMI does not comment on pitchers like Strasburg who have never been tested in our lab, nor does ASMI disclose information on pitchers who have been tested in our lab.  

The specific mechanical flaw discussed by Tom Verducci in his Sports Illustrated story was the position of the throwing arm at the time the front foot contacts the mound. The statement in the current story that "a pitcher's foot should land precisely when his arm reaches maximum external rotation" is grossly inaccurate and misleading to your readers. In two decades of testing pitchers, ASMI has never measured a single pitcher reaching maximum rotation of his shoulder when his foot lands. Our biomechanical data show that when the front foot makes contact with the mound, the shoulder should have between 35 degrees and 80 degrees of external rotation (as reference, "0 degrees" is when the forearm is horizontal and "90 degrees" is when the forearm is vertical). This is an important position to understand, as pitchers with their throwing forearm below this range or above this range may have improper timing between their arm and body leading to higher stress on the shoulder or elbow. (Professional coaches understand this, but readers of the Kilgore article may be misled by the incorrect description. Such errors could have been avoided if Mr. Kilgore had interviewed me directly before writing this story.)

There will always be some injuries in baseball; as Jim Riggleman quipped, the only way to make sure pitchers don't get hurt is to not let them pitch. But teams need their pitchers to pitch. In my opinion the more interesting story is how the Nationals and other MLB teams use biomechanics, strength & conditioning, amount of pitching, nutrition, and medical treatment to optimize the performance and health of pitchers.