Washington

Baseball fans are starting to question Chicago Cubs superstar Sammy Sosa's impressive hitting record, in the light of his use of an illegal 'corked' bat to boost his slugging power. But physicists say that the bat did little, if anything, to improve his hitting.

Sosa, who has hit 505 home runs, was caught in the act when his bat shattered in a game on 3 June against the Tampa Bay Devil Rays. He denies intentionally using the bat in the game — he claims he uses it to impress fans during practice — but was suspended for eight games.

Physicists say, however, that Sosa gained almost no advantage by using the bat, which was hollowed and filled with a small amount of cork. Using a lighter bat would help Sosa swing harder but would actually lessen the energy transferred to the ball, according to Alan Nathan of the University of Illinois at Urbana-Champaign, who recently studied ball–bat impacts (Am. J. Phys. 71, 134–144; 2003). “If there is a net advantage, it would be small enough that it wouldn't be worth writing home about,” Nathan says.

Robert Adair, a professor emeritus at Yale University and former official physicist of Major League Baseball, agrees that the perceived advantage of corking a bat is largely “superstition”. It is deemed illegal because traditionally bats are supposed to be solid wood. “Corked bats aren't a mortal sin,” he says. “Maybe just a venial one.”