From the Boston Globe
By Nancy Shohet West, Globe Correspondent
When James Sherwood, a professor of mechanical engineering at the University of Massachusetts at Lowell, sees his lab assistants swinging baseball bats, he doesn't worry that they're goofing off.
Swinging bats and discussing the finer points of the game are part of the job for them as they assist Sherwood in UMass-Lowell's Baseball Research Center.
It is a basement laboratory designated by Major League Baseball as the official "test kitchen" for its baseballs, as well as for all bats used by high schools and NCAA league games.
Sherwood, who has served as the Baseball Research Center's director since it was first funded in 1998, said it was set up by Major League Baseball, the governing organization of the National and the American Leagues, to study aspects related to the science of baseball. Then in 2000 a subtle change occurred within the game.
"In April of 2000, players seemed to be hitting far more home runs than they used to," Sherwood recalled. "Fans became suspicious that the balls were juiced."
Major League Baseball did not share those suspicions, but the organization responded to the fans' sentiments by asking the center to launch a monthlong quality control study on its baseballs.
The study took Sherwood and some associates to every corner of baseball manufacturing: from Alabama, where the tiny rubber globe in the center of a baseball is made; to Vermont, where the wool wrapped around the rubber core is spun; to Tennessee, where the leather for the outside of the ball is manufactured; to Costa Rica, where the individual components that make up baseballs are assembled into a whole.
They found nothing suspicious, but Sherwood said they made recommendations for how each factory could improve upon its quality control standards. Before that the lab had focused mostly on NCAA bat testing, but the one-month study turned into a permanent role for the lab's testing baseballs.
"A few years ago, when fans raised a lot of concerns, testing became very important to us and we grew to rely on their credibility in this area," said Pat Courtney, a spokesman for Major League Baseball. "The engineers at the Baseball Research Center in Lowell have worked on a number of different baseball-related issues and tasks for us, and we have relied on their expertise."
The Major League Baseball organization sends Sherwood eight dozen balls as a sampling of those that will be used in the regular season and eight dozen World Series baseballs before the playoffs begin. Upon arrival at the Lowell lab, the balls are stored for two weeks in a controlled climate of 50 percent humidity and 70 degrees.
The team of engineers then conducts "coefficient-of-restitution" testing on the balls, which Sherwood describes as "a measure of the liveliness of the baseball." To do that, they use a pitching machine to throw a ball at a wood block and measure how fast the ball bounces off the block. The baseballs are squeezed in a press to measure their hardness. After that, it's time for dissection.
"We take a sampling of 12 baseballs and peel them layer by layer, like an onion," Sherwood said. They look at how each layer is constructed and compare it to manufacturing specifications.
"We report our findings to MLB as part of a compliance study," Sherwood said.
Sherwood says they have never found a single example of a ball that did not meet Major League Baseball standards.
The work that Sherwood, his one full-time staff engineer, and a crew of six to 12 student lab assistants conduct continues year-round, particularly in their certification of bats. "Unlike balls, there is some variation among the bats used at the high school and college level. The engineers who make them have a bit of freedom," Sherwood said.
"What we're attempting to do is level the playing field, no pun intended, with respect to the performance of those bats," he said.
To test bats, the center established a "ball exit speed ratio." In the past, Sherwood said, bat standards were based on maintaining a game in which a pitcher still has time to react even when a ball is being hit at top speed. Sherwood successfully proposed a change in approach that bases the maximum allowable speed ratio to be relative to wood bats of comparable length and weight.
Everyone who works in the lab is a baseball enthusiast, Sherwood said. "The guys here talk about baseball all the time," he said.
There was a time when Sherwood's group sometimes pressed minor league players into service testing their bats, but automation for the most part has replaced baseball players.
Does Sherwood watch baseball when he's not in the lab?
"Once the game is under way, I'm just a regular fan," he said. "Actually I grew up just an hour outside of Cleveland, rooting for the Indians, before moving to this area and becoming a Red Sox fan. So no matter what happens in this series, I'll be happy."