A related article about the limits of throwing ability... http://www.slate.com/articles/sports/sports_nut/2005/04/pitcher_perfect.html
"In almost every measurable physical activity, athletes show improvement over time. Jumpers jump higher and farther, and runners and swimmers go faster. Since the late 1950s, the high-jump world record has improved by more than 10 percent, the 100-meter-dash mark has improved by 5 percent, and swimming's best 100-meter freestyle has dipped 12 percent. Pitchers, though, don't seem to be getting any faster. Pretty much every generation since the early 1900s has boasted a supposed 100-mph pitcher"
"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."