October 28, 2021

I, Science

The science magazine of Imperial College

Today we will see Maria Sharapova finally step back onto centre court for the Wimbledon Ladies Final. Undeniably a pleasure to watch, the annoyingly loud ‘grunts’ that Sharapova is now famous for are much less pleasing on the ears.

Reaching levels of up to 100db, Sharapova’s exhalations can be distracting for both viewer and her opponent. She is not the only one who is accused of excessive noise. Rafael Nadal and the Williams sisters are also guilty of letting out high-pitched shrieks whenever they strike the ball.

Though penalties for these loud noises are few and far between, the official party line of the International Tennis Federation is that a player can be issued penalty points for excessive grunting. To date, experts have been unsure as to the exact level of distraction faced by the opponents of excessive grunters. Does it merit more frequent penalisation? Tennis legend Martina Navratilova believes grunting to be a form of cheating as it masks the sound of the ball striking the racket, an important aspect of planning your returning shot. This may indeed be true, as researchers from the Universities of Hawaii and British Columbia have begun to investigate.

33 undergraduate students took part in a recent study where they were asked to watch clips of professional tennis players executing both forehand and backhand groundstrokes. Half of the clips were accompanied by white noise at a level of 60db and the other half were not. The students were then required to judge the direction of the shot. Their speed and accuracy was measured and the results analyzed.

The study found that when an additional sound  (representing the grunting) accompanied a clip of a tennis shot then the participants were significantly slower in their decision-making and also made many more mistakes. By interpreting these results with respect to the average speed of a tennis ball in a professional match, the study found that on average the presence of a grunt caused a 21-33ms delay in the opponent’s response.  This would be the equivalent of a player being wrong footed by their opponents grunting once in every game. Professional grunters may therefore be giving themselves a one-point advantage in every game throughout an entire match.

This response delay could be caused by one of three things. Firstly, the grunt could indeed mask the sound of the ball striking the racket. When two objects collide the sound is vital to the visual perception of the collision. Secondly, the grunt may draw auditory attention away from the collision. Thirdly, the grunt may draw visual attention away from processing the visual event of the ball hitting the racket. However, monitoring eye movements of the participants did show that the presence of a sound did not alter the eye movements. Therefore it is simply visual attention that is altered.

However the grunting causes a distraction, this study has shown that the presence of these sounds does decrease the opponents ability to accurately judge the direction of the shot and also reduces the amount of time they have to respond to the shot, So a bit of homework for you this week, watch Sharapova in the final and see if she manages to grunt loudly enough to put Petra Kvitova off her game.

Image from Wikipedia.com