Dark Bilious Vapors

Maybe it only looks like the outer limit for pitchers is stable at around 100 mph because we can't consistently and accurately measure minute improvements in speed. When it comes to flamethrowers, after all, it's hard to figure out what's the truth and what's a tall tale. [Cleveland Indians pitcher Bob] Feller once sent a fastball zooming by a speeding motorcycle. Maybe the ball really was traveling at 104 mph, as the organizers of the stunt claimed. Or maybe not.

Still, according to experts in biomechanics, that 100-mph ceiling isn't an illusion—it's a basic property of human physiology. A pitcher generates momentum by rocking onto his back leg and thrusting forward. After that he rotates his pelvis and upper trunk, then his elbow, shoulder, and wrist. Intuitively, it seems like building up the muscles in the legs, upper body, arm, and shoulder would generate more force and make his arm move faster. The reality: There's a point when more torque doesn't yield a faster pitch. It simply causes tendons and ligaments to snap, detaching muscles from bones and bones from one another. (Tendons connect muscles to bones; ligaments connect bones to each other.)

Glenn Fleisig, a biomechanical engineer who studies pitching at the American Sports Medicine Institute in Birmingham, Ala., has calculated that about 80 Newton-meters of torque act on an elite pitcher's elbow when he throws a fastball. The ulnar collateral ligament connects the humerus and ulna—two of the bones that come together in the elbow. To test the outer limits of the ligament's strength, Fleisig subjected cadaver elbows to increasing amounts of rotational force. These experiments showed that an average person's UCL snaps at about 80 Newton-meters. Smoky Joe Wood said that he threw so fast he thought his arm was going to fly off. It turns out he wasn't far from the truth.
--Noam Scheiber

Len on 04.11.05 @ 05:28 AM CST