Winning ugly: In tennis, grunting works, but is it fair?

Listen up, tennis fans, it’s quiz time. That explosive, guttural grunt issued by some of the world’s best-known tennis players at the moment of contact with the ball is: a) a rude, pointless and annoying vogue that should be reined in by officials of the International Tennis Federation; b) a forceful but involuntary exhalation of air that signals fierce exertion; or c) a habit that has the effect of -- and is probably aimed at -- distracting and intimidating an opponent. If you picked a, you have a number of sympathizers on the Booster Shots staff. If you picked c, you have some new evidence to support your position.

A pair of psychologists -- one from the University of Hawaii, the other from the University of British Columbia -- conducted a study, which was published late last week in the journal Public Library of Sciences. A grunting player, they found, has a “competitive edge” because his or her grunting impairs an opponent’s ability to judge the direction and pace at which the grunter hits the ball.

The researchers came to that conclusion after putting 33 undergraduate subjects in front of a video screen, where they viewed, as if standing at the baseline ready for play, 374 film clips of different tennis shots. At the moment of impact, the subjects were to make an immediate prediction of the direction in which the ball would travel.

In half of the clips, subjects heard nothing but the sound of the ball bouncing and the impact of the ball on the racquet face. During the other half of the clips, the researchers played a 60-decibel blast of uniform white noise at the moment of impact. While loud enough to intrude on the sound of the tennis player’s hit, 60 decibels is considered a “comfortable” volume that should not startle or harm a subject. (It’s also quieter than Maria Sharapova’s most forceful grunts, which have clocked in above 100 decibels.)

When the white noise competed with the sound of impact, subjects were notably slower and less accurate in their predictions about the ball’s likely trajectory. The competing sound slowed and impaired their ability to predict the ball’s likely course very early (as evidenced by the poorer predictions they made when the film clips stopped at the moment of impact). And it continued to slow and impair their judgments even when they were allowed to watch the ball leave the racquet face.

Professional tennis players may have sharper intuitions about the direction and pace at which a ball will travel than do Canadian undergrads. But the researcher surmised that pros very likely do rely on their perception of the sound of a ball being hit to make timely judgments about where to be for the next shot (and how soon they need to be there). If an opponent’s grunts slowed the spatial judgment of a professional tennis player as badly as it did that of the study subjects, the ball could travel two extra feet in the course of a typical rally before the player even began to calculate its direction. And if grunting degraded the accuracy of her judgment as badly as it did the study subjects’ predictions, the researchers calculate, the person across the net from a grunter would end up out of position for the coming shot once per game.

“Our data suggest that when they grunt, they are gaining an unfair advantage,” wrote the authors. In that, they appear to agree with tennis great Martina Navratilova, who said last June that the grunting is “cheating, pure and simple. It is time for something to be done.”

-- Melissa Healy / Los Angeles Times