D: Hey Yaël, you play tennis, right? Maybe you can give me an insider’s point of view on one of the controversies in tennis: how grunting affects the game.

Y: You’re talking about how tennis players often grunt while hitting the ball, right?

D: Right. I read that the sound can get up to 100 decibels, which is basically as loud as a motorbike.

Y: It’s true. Some tennis players say it doesn’t bother them, but others say the grunts distract them from hearing the ball hit the racket, which makes it harder to predict where the ball will land. A group of sports psychologists decided to test whether grunting really did have this effect. They conducted a series of experiments where participants who were experienced tennis players watched a professional tennis match and had to predict the ball’s trajectory and where it would land. The researchers manipulated the intensity of the grunts heard in the game, so sometimes they were louder, while sometimes they were softer. They found that grunting did have an effect on the game, but not the one tennis players often complain about—that it makes them mistake where the ball will land more often. Participants made just as many errors predicting where exactly the ball would land when the grunting was intensified as they did when it was muted. The difference was that players would systematically guess the ball would fly farther when the grunts were amplified.

D: Now I want to play a game of tennis to test this out for myself. What do you say to a round of singles?