Whatan Arm Analysis Shows How Pitchers Addheat to Create a Blazing Fastball

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Byline: Rachel Saslow The Washington Post

What makes Washington Nationals rookie Stephen Strasburg such an intimidating pitcher? The 22-year-old can throw triple-digit fastballs while guiding the ball to an exact spot in, or not quite in, the strike zone. His curveballs seem to fall off a cliff. His changeup -- a slower pitch, meant to confuse the batter -- clips along at 89 mph, the speed of some pitchers' fastballs.

To his fans, coaches, teammates and especially his strikeout victims, Strasburg's talent seems inexplicable, a supernatural force: "There's no rhyme or reason. He's just better than everybody else," says Rob Dibble, a MASN-TV commentator who once threw 99-mph fastballs of his own.

"It's a God-given talent," says Steve McCatty, the Nationals' pitching coach.

But, in truth, baseball is a game of numbers and physical laws. Experts on pitching and biomechanics say that Strasburg is a genius at moving energy through his body, never making a motion too early or too late, never creating an angle in his body that's too acute or obtuse.

Strasburg's complex series of perfect motions starts when he raises his left foot. The energy moves from the legs to the pelvis, to the trunk to the shoulder to the elbow, to the wrist to the fingertips -- and, finally, to home plate. Scientists call this the kinetic chain, or the process of transferring energy from one link in the body to the next. Coaches call it coordination.

"His mechanics are sound and very fluid," Nationals General Manager Mike Rizzo says. "The effort he exerts to get to maximum velocity is very minimal for his miles per hour. a The effortless delivery translates into more command over the pitch." In other words, Strasburg makes throwing a ball 100 mph look easy.

Unfortunately, the rookie right-hander was placed on the 15-day disabled list last week by the Nationals because of inflammation in his pitching shoulder. The move is retroactive to July 22, a day after he made his last appearance. The No. 1 overall pick in the 2009 amateur draft was scratched minutes before he was to make his 10th major league start because his right shoulder felt stiff while he was warming up in the bullpen.


Glenn Fleisig, the research director at the American Sports Medicine Institute in Birmingham, Ala., has analyzed the mechanics of about 2,000 baseball pitchers since 1987. (ASMI was founded by orthopedic surgeon James Andrews to understand and prevent injuries in sports. "The mission was to put himself out of business," Fleisig says.)

Major league coaches send pitchers to the ASMI laboratory, which has a regulation-size space to throw the ball: 60 feet, 6 inches, from rubber to plate. (Little League, high school and college players also go to ASMI for evaluation.) Fleisig sticks about 25 sensors on the pitcher and points eight cameras on him while he throws the ball. It's the same technology used for creating special effects in movies and video games.

The sensors and cameras connect to a computer, which spits out a 15-page document called a "biomechanical analysis of pitching delivery." How fast does the pelvis rotate, in degrees per second? What's the angle of the lead knee when the foot hits the ground? Is the trunk tilted forward at the moment of ball release, as it should be? (The ideal tilt, for example, is in the range of 37 to 44 degrees.)

"What makes a good pitcher is not that he bends his elbow or knee the right way," says Fleisig, who has not analyzed Strasburg in the laboratory. "What makes him good is that he doesn't have a weak link in his chain of events or a mistimed motion."

Aspects of Strasburg's anatomy, including his height, hands, legs and the soft tissue in his shoulder, help him throw the ball faster, but there is no paper-doll ideal for what a great pitcher looks like. The 6-foot-10 Randy Johnson, who retired this year, didn't have a big lower half to power his windup, and the Astros' Roy Oswalt, who is listed at 6 feet tall, doesn't have height. …