Not the whole story on Stephen Strasburg's delivery
I read with great disappointment Adam Kilgore's March 10 Sports story about Washington Nationals pitcher Stephen Strasburg ["Should Strasburg tweak his delivery?"].
It was inaccurate to say that I made a "definitive assertion" that a specific mechanical movement led to Strasburg's injury. Rather, I agree with Dr. Tim Kremchek, who was quoted as saying that it is impossible to know for sure how Strasburg's injury happened.
Findings on how mechanical flaws correlate with pitchers in general, not one pitcher in particular, are based on thousands of pitchers who have been tested in the biomechanics lab of the American Sports Medicine Institute (ASMI), including hundreds of professional pitchers. Test data have led to dozens of published scientific studies that 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; nor does it comment on pitchers such as Strasburg who have never been tested in our lab.
The mechanical flaw discussed by Tom Verducci of Sports Illustrated was the position of the throwing arm when the front foot contacts the mound. The statement in Kilgore's story that "a pitcher's foot should land precisely when his arm reaches maximum external rotation" was not accurate. 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 35 to 80 degrees of rotation.
This is important to understand, as pitchers with their throwing forearms 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.
In my opinion, the more interesting story is how the Nationals and other major league teams use biomechanics, strength and conditioning, amount of pitching, nutrition, and medical treatment to optimize the performance and health of pitchers.
Glenn S. Fleisig,
The writer is research director at the American Sports Medicine Institute. A longer version of this letter is available at http:/