Fast pitchers push batters' ability to respond

A white blur explodes from the left hand of Reds reliever Aroldis Chapman. By the time the batter is able to see the speeding ball and his brain decides whether to react, 130 milliseconds have elapsed. The ball is one third of the way to the plate.

Then it takes another 100 milliseconds or so for the batter's muscles to tense up, and 150 milliseconds for him to swing the bat, and . . .

Thunk! The ball, after 380 milliseconds, has already landed in the catcher's mitt.

Such are the parameters at the outer limits of elite human performance. Chapman threw a 105.1 m.p.h. fastball last month against the San Diego Padres, the fastest yet recorded with sophisticated new camera-based technology used by Major League Baseball, and such speeds push the limit of how fast a batter can react. Skilled professional hitters can handle a triple-digit fastball, especially if the pitcher doesn't mix in off-speed stuff, but 105?

Good luck, said James A. Ashton-Miller, a professor of mechanical and biomedical engineering at the University of Michigan.

"He's going to definitely have to be focusing on the task, and not worrying about what's for dinner," Ashton-Miller said of the batter.

Such speeds also are pushing what the pitcher's elbow and shoulder can handle - a limit that scientists have measured in part by testing cadavers.

How does Chapman do it? He has at least two characteristics in his favor. Like many fireballers, he is tall, listed at 6 feet 4. The longer the various body parts - trunk, arms, even fingers - the more torque the pitcher can exert on the ball, assuming he has the muscle strength and coordination, said Glenn S. Fleisig, research director at the American Sports Medicine Institute in Birmingham, Ala.

Former Phillie Pedro Martinez, though not terribly tall, was said to generate his speed as a young pitcher in part because of his long, whiplike fingers.

Another key to speed, Fleisig said, is flexibility. When preparing to unleash high heat, Chapman and other top pitchers snap their forearms backward so they are fully horizontal to the ground.

Fleisig warned that in adults, this flexibility cannot be improved with training. The range of motion is due to genetics and to how much a player throws when growing up.

A young pitcher will actually develop subtle, permanent changes in his bones and ligaments. The humerus bone in the arm can even become slightly twisted, enabling faster pitches, but it is a delicate balance, Fleisig said. Too much throwing, especially on a year-round basis like some of today's youths do with elite travel teams, leads to injury.

Other elements of speed include proper mechanics, including the timing of when a pitcher rotates his hips and strides forward, and proper conditioning, Fleisig said.

Even if everything is done correctly, throwing fastballs for a living can be injurious, and is one of the most demanding activities in sports. When the pitcher's forearm accelerates backward, it feels as if a 50- to 55-pound weight is hanging from his hand during that instant, Fleisig said.

Then, at the time the ball is released, the force exerted on the shoulder joint is about equal to body weight, the researcher said.

"It's as if someone is trying to pull his arm out of his shoulder with 200 pounds of force," Fleisig said.

So how is Chapman's speed measured?

Since 2007, all 30 major-league stadiums have been outfitted with PITCHf/x, a camera-based system devised by Sportvision Inc. Scouts still use radar guns, but the cameras are more consistent, said Cory Schwartz, director of stats for MLB.com. The devices are mounted in the stadium, typically high above the first- and third-base lines and in center field, and are used to plot a three-dimensional trajectory of each pitch.

Of the fastest 40 pitches since the systems were installed, Chapman has thrown 25 of them, Schwartz said. And he didn't join the Reds until late this season.

The fastest pitch not thrown by Chapman came from Neftali Feliz of the Texas Rangers, at 103.4, Schwartz said. Joel Zumaya of the Tigers hit 104.8 in the 2006 postseason, but the camera system in use then was a prototype.

Schwartz said it is hard to compare these speeds with those measured by radar gun, which can vary based on where the operator is sitting, among other factors. The PITCHf/x system appears to be more reliable, though it can vary up to 1 m.p.h. from ballpark to ballpark, said Alan Nathan, a professor emeritus of physics at the University of Illinois in Urbana-Champaign.

That could be because the cameras, though carefully tuned and positioned in advance, may sag slightly when the stands fill up with spectators, he said.

In any event, it's clear Chapman is throwing about as fast as a person can throw, said Fleisig, the sports medicine researcher.

"If pitchers were able to train themselves to pitch faster, they would tear things," Fleisig said. "Their ligaments and tendons wouldn't be able to withstand it."

So what speed will the Phillies actually be seeing from Chapman?

The PITCHf/x system measures speed at a location 50 feet from home plate - just a few feet after the pitcher releases the ball, Nathan said. By the time it reaches home plate, he said, Chapman's top fastball has slowed to about 95 m.p.h. because of drag - resistance from the surrounding air.

To calculate how much time the batter has to react, the key number is the ball's average speed over the entire duration of the pitch - generally about 5 percent slower than initial velocity. That's just under 100 m.p.h. an hour for Chapman, Nathan said.

The pitcher's rubber is 60 feet, 6 inches from home. But by the time he completes his throwing motion, the typical pitcher releases the ball about five feet closer to home.

Assuming Chapman let go of his record fastball about 55 feet from home plate, the ball got to the batter in 380 milliseconds, Nathan said. That is pretty much as fast as a batter can respond, though some batters may improve their chances by starting to move in anticipation of the pitch, said Michigan's Ashton-Miller.

Most will simply miss, as hitters are batting .196 against the young reliever. Said Schwartz, the MLB.com official:

"Good luck with that."