Finding the Sweet Spot: The Science of Baseball

By Clifton B. Parker

Imagine a batter, with muscles as tense as coiled springs, like a predatory animal about to pounce, holding a smooth, round club of white ash as he waits for the precise instant to swing at a cowhide-wrapped ball hurtling toward him at up to 99 miles per hour.

At this speed it takes about four-tenths of a second for the ball to travel the 60 feet, 6 inches from the pitcher’s mound to home plate.

Baseball is a sport of failure, where averaging three hits in 10 at bats can earn a player a ticket to the Baseball Hall of Fame, a success ratio that seems modest compared to other sports.

Ted Williams, the legendary slugger who took an interest in the physics of the swing, once said, “Hitting a baseball is the single most difficult thing to do in sports.” Williams understood that behind the emotion, sweat and muscle of baseball lies a game dictated by the immutable laws of science.
The scientific collection and evaluation of baseball statistics has been occurring for decades, but the issue has heated up in the last couple of years with a debate between the old way of evaluating talent and building teams and a new approach based on the scientific evaluation of statistics.
And the mechanics of baseball itself—how batters hit, how pitchers throw—is grounds for
discovery as well.

The Sports Biomechanics Laboratory at UC Davis has taken a great interest in the scientific principles governing baseball since opening in 1979. Led by engineering professor Mont Hubbard, researchers at the lab have explored a wide range of athletic activities through modeling, simulations and measurements. Many of the researchers are graduate and undergraduate students in mechanical and biomedical engineering.

“These studies could aid in how a hitter or pitcher approaches pitch selection,” said Hubbard, “and in the design of pitching machines to help pitchers hone their curves, fastballs and sliders, among other possibilities.”

ON THE BALL

Debunking myths is a sport at the Sports Biomechanics Laboratory. Take the conventional wisdom that says a hitter can drive a fastball farther than a curveball. Players, coaches and managers have long embraced this belief, all the way back to when the curveball was “invented” in the 19th century, sometimes setting pitching strategy around it.

The opposite is true, says Hubbard. The reason: the spin of the ball.

Curveballs are thrown with topspin so the top of the ball rotates in the direction of flight. Being hit by the bat throws them into reverse, giving them backspin—and lift that carries them farther. Fastballs are thrown with backspin; they spin the other way when hit, have less lift and sink faster.

To generate the right amount of batted backspin, Hubbard says, the batter should connect with the ball a bit below the center. Hitters don’t have much time to think about it, the professor notes. It’s a blink of chance. The collision of a ball on the bat lasts only about 1/1,000th of a second.

Hubbard’s surprising discovery has attracted media interest nationwide. National Public Radio described his findings as “the most intriguing piece of baseball writing published” in recent months.

To compare curveballs with fastballs, Hubbard and his graduate students used multiple high-speed cameras to track trajectories of pitches thrown by the U.S. Olympic baseball team during the 1996 Atlanta summer games. Emboldened with all the relevant data, they did what not even Barry Bonds has yet done and published a paper on “how to hit home runs.” The paper, which appeared in the November 2003 issue of the American Journal of Physics, was co-authored by Hubbard, along with graduate student Gregory Sawicki and Cambridge University colleague William Stronge.

Much of the research relied on understanding the varying aerodynamics of a baseball, an idiosyncratic object itself.

A Major League-approved baseball is a 5-ounce sphere of yarn wound around a cork-rubber center and wrapped in two pieces of dumbbell-shaped cowhide stitched together with 216 red cotton stitches. The stitching creates the familiar raised pattern on the ball, with opposing wide and thin areas. The seams disturb the air as they rotate, affecting the aerodynamics of the ball.

Hubbard says the most critical factor in hitting a homer is bat speed.

“The faster, the better,” says Hubbard, who adds that much more is to be learned. “Research is an incremental process. We often elaborate on what we learned before, taking it one knowledge step at a time.”

Hubbard is also interested in learning more about batting stances, the strike zone, swing mechanics and especially the spin vectors of pitched balls.

“What happens when you throw a baseball and it is spinning rapidly toward home plate?” asks Hubbard. “What happens as a result of the way you’re holding the ball before you release it?”
One of Hubbard’s graduate students, Leroy Alaways, wrote his 1998 doctoral dissertation on whether a curveball really curves or is an optical illusion—a long-running debate in baseball circles, believe it or not.

Alaways found that a pitched ball can curve in the hands of a skilled pitcher as much as 18 inches. The reason boils down to this: A pitcher throwing a curve imparts spin to the ball that drags a layer of air across one surface of the ball faster than it does across the opposite surface.

Hubbard and Alaways have worked together on next-generation machines capable of pitching just like the human big leaguers. Hubbard says the Los Angeles Dodgers recently
expressed interest in a pitching machine that Alaways helped develop.

“While it’s just an inquiry, it’s nice to have your existence validated,” Hubbard says. “It’s been hard to get a nickel in funding from organized baseball. But maybe that’s beginning to change.”
Hubbard has also taken a leading role in organizing the fifth International Conference on the Engineering of Sport, which will be held Sept. 13–16 at UC Davis. This event will serve as a forum for the discussion of technical issues related to sports research. Previous conferences in England, Australia and Japan have attracted speakers and participants from throughout the world. The organizers are making a special effort to include sessions on practical applications of sports research.

Baseball’s not the only sport explored at Hubbard’s Sports Biomechanics Laboratory. In their lab setting in the Academic Surge Building, researchers have investigated the motions and mechanics of skateboards, boomerangs, pole vaulting, javelin throwing, ski jumping, bobsledding, water skiing, golf putting, roller coasters, bicycling and Frisbees, to name a few. Topics are as varied as the wide world of sports.

At heart, Hubbard is a fan whose interest in the game extends back to his childhood in Altavista, Va., where he grew up rooting for the New York Yankees. “When I was a kid I’d go down to the ball field and play all day, play and play, and by evening I’d be hungry and dehydrated.”

Outside the lab, Hubbard has quenched his hunger for baseball in other ways, including coaching his son’s Little League team and participating in research discussions in the Society for American Baseball Research, an organization of a few thousand members nationwide—many of them academics like Hubbard—who study baseball.

TOOLS OF THE TRADE

Baseball, as the evolutionary scientist Stephen Jay Gould once noted, relishes the keeping of statistics.

Alumnus Gary Huckabay ’94, M.B.A. ’98, goes beyond simple number-crunching. The founder of Baseball Prospectus, Huckabay believes it’s time baseball cut through the hype surrounding players and teams. His annual publication pulls no punches when statistically examining each player and every organization from the minors to the majors.

“We want to compare players on an apple-to-apple level,” says Huckabay, who also is running a start-up company in Sacramento in addition to his Prospectus duties.

Huckabay espouses “sabermetrics,” a brand of baseball analysis that the writer Bill James helped launch in the 1970s. Last year’s best-seller about sabermetrics, Michael Lewis’ Moneyball, was an exclamation point that sabermetrics had finally arrived in the mainstream.

The tone of sabermetrics, whether you’re reading James or Prospectus, is irreverent and revolutionary—indeed, these are people trying to change the way baseball thinks, and there’s a lot of money at stake, at least for teams and players.

Sabermetrics considers statistics like batting average and runs batted in—the stuff of newspaper
box scores favored by fans for decades—downright obsolete. Rather, sabermetrics examines performance within a number of variables relative to context—ballpark, team, league and other fators. Think of Albert Einstein’s relativity theory as applied to baseball, and you’ve got an idea about the complexity of sabermetrics.

Instead of batting average, a sabermetrician touts “on-base average” to measure offensive performance, arguing that it expands on batting average by including walks and the times batsmen are hit by the ball. And getting players on base, after all, is ultimately how teams score runs.

“The information revolution has finally arrived in baseball, and now it’s about accountability,” says Huckabay. “Subjectivity and intuition will always have their place, but they will have to exist within a frightening new reality of accountability that’s greater than ever before.”

Huckabay, who worked for several years as a computer resource specialist at UC Davis, explains that Major League Baseball has been insulated through the years from many of the competitive pressures faced by other industries. Its anti-trust exemption and hallowed status as America’s national pastime have made this possible.

“Not anymore,” says Huckabay. Multimillion-dollar player contracts should be approached with the same due diligence a venture capital firm exhibits in deciding whether to invest in a product or company. This means collecting data—lots of it—and sometimes the findings are revealing.

“One result is an increased appreciation of the talent of a large number of both minor and major league players,” he says. “Teams are beginning to understand that there is no bright dividing line between a minor leaguer and major leaguer, and that they have more options when putting together their major league rosters.”

His data have yielded other surprises: Huckabay notes that baseball people typically think players peak in their early 30s, while research shows that a player’s best years usually happen around age 26–27. This has enormous implications for teams deciding whether to give a player of a certain age a long-term, expensive contract.

Pitch counts—the number of pitches thrown by a pitcher in one game—are another area of debate. Some in baseball think it’s “macho” for a pitcher to complete a game he started. But Huckabay points to research on the prevalence of injuries and poor performances after a pitcher runs up high pitch counts in a game.

Not surprisingly, given the challenges to the status quo, some baseball insiders have qualms about the rise of sabermetrics.

Says Huckabay, “There are longtime scouts who say, ‘What, you’re going to replace me with a computer? You guys never played baseball.’ Sabermetrics threatens people and their livelihoods.”

He adds, “The fear among some is that it’s going to somehow damage the game. Will its poetry be lost amidst a blizzard of derived numbers? Not in the slightest. Because better players will be playing.”

TAKE ME OUT TO THE BALLPARK

What does the real world of baseball say about sabermetrics?

Ned Colletti, assistant general manager for the San Francisco Giants, says statistics can reveal much about a player, but teams do not rely on statistics alone when evaluating a player. The human element of scouting plays a vital role.

“In many ways, a scout projects the future, while statistics review the past,” Colletti says. “Both go hand-in-hand in evaluating players, with one supporting the other.”

While statistics can quantify a player’s strengths and weaknesses, a scout can gauge whether the weaknesses have a chance to be corrected. Scouts can assess qualities like whether the player is a quick learner and a hard worker and whether he would be motivated or softened by a long-term
contract.

And when it comes to investing in those large player contracts, Colletti agrees with Huckabay that a team must approach the decision with due diligence.

“Even a player as great as Barry Bonds is a risk,” Colletti says. “Whenever we are going to invest that amount of salary, we find out as much as possible about the player. While players possess a unique physical talent, they are still human.”

Unfortunately, teams cannot always be as selective as they’d like. Sometimes multi-year contracts are a necessity to successfully compete against other clubs. “Competitive offers from competing teams can supercede a team’s best interests, which might be a one-year deal,” says Colletti.

Rex Peters, head baseball coach at UC Davis and a former player himself, also sees a role for science and statistics in baseball.

“Studying the physics of the game has relevance to both hitting and pitching, and this information is valuable as it is digested by the baseball world,” says Peters, who played four years in the Los Angeles Dodgers minor league system. “And statistical analyses have value in how we determine high value players and strategies.”

He agrees with Huckabay, for example, that on-base average is a better gauge of performance than batting average.

“Baseball is a game of numbers and percentages,” says Peters, with managers and players seeking the best odds in the countless match-ups of a nine-inning game. But he cautions, “Sometimes too much can be made of statistics.”

Back in the 1980s Major League Baseball added a statistic, “game-winning RBIs,” only to withdraw it once it was clear some winning hits come early in the game as well as late in the game. And so game-winning hits wasn’t truly measuring “clutch” performance under late-inning pressure situations.

Peters also agrees with Hubbard’s finding that curveballs go farther than fastballs. “That sounds logical when you think about the physics of it.”

He would like to see two areas of baseball performance receive more scientific attention. One is “visual training,” or how to improve the ability of a batter to track the path of a baseball.

“If you see the ball well, that makes a lot of difference, especially for a hitter. The eyes are the control tower from which everything depends.”

The other is the mental aspect of the game. Success is about motivation and preparation, concentration and determination. Call it baseball intelligence or pure smarts, much of the game depends on players making the most of opportunities. “How do you measure this in numbers?” says Peters.

One of the books he encourages his players to read is Heads-up Baseball: Playing the Game One Pitch at a Time by Tom Hanson and Ken Ravizza. The book provides strategies for developing such skills as concentration, mental preparation and staying in control under pressure.

“We spend a lot of time talking with our kids about these issues, which are transferable from the baseball diamond to adult life.”

While statistics and experiments offer insights into the dynamics of the game, Peters acknowledges the role of experiential learning as well.

“Playing countless games, swinging at countless pitches and taking countless ground balls increase a baseball player’s game intelligence and preparation,” he says.

While science can shed light on many aspects of baseball, much of what makes baseball fascinating are the countless myths and mysteries. And as Peters says, it all starts with the people playing the game.