Noise seems to be a bit of a problem in major sports tournaments. For many, vuvuzelas were the scourge of the 2010 World Cup in South Africa. So much so that the BBC looked into ways of muting them on live sound feeds.
Now, with Wimbledon in full swing, an old favourite is back - the eponymous tennis grunt.
Hand drills clock in at a loudness of around 98dB (decibels). Motorcycles are a bit louder, at 100dB. The grunts of Michelle Larcher de Brito, who defeated Maria Sharapova in the second round of Wimbledon, reportedly clock in at 109dB, with Sharapova not far behind at 101dB.
A number of players - most recently Andy Murray in March - have complained that grunting confers an unfair advantage. The argument goes that at best, grunting is distracting, and at worst, it masks the noise that the ball makes when it comes into contact with the racket, which is a potentially useful source of information about the speed and trajectory of the shot. But is there any truth in it?
Scott Sinnett at the University of Hawaii and Alan Kingstone at the University of British Columbia decided to investigate this in 2010. They took 384 video clips of a professional player hitting a tennis ball across the court in different directions, that either did or did not include a grunt. (For the purpose of this study, to control for individual variations, a grunt was represented by white noise that lasted for half a second.) The task of 33 participants, to whom these videos were shown, was to decide which direction the ball was being hit across the court, as quickly and as accurately as possible. To further add to the difficulty, the videos were clipped so that they either finished at the time of contact with the ball (the “hard” condition), or a short time afterwards (the “easy” decision).
Sinnett and Kingstone looked at response times and accuracy, and found some striking effects. When a grunt sound was present, participants were much slower and made more errors in their response. Similarly, the difficulty of the decision had an effect - when the video stopped at the point of ball contact, participants tended to be slightly slower to respond, and make more errors, than when the video was clipped to end a short time after contact.
So it seems that if you grunt when you hit the ball, you might be able to throw your opponent off for just enough time to make them miss, or misjudge which direction you’ve hit it. Sinnett and Kingstone point out that if a shot is travelling at 50mph, the relatively small delay in response that grunting causes (about 30ms) would result in the ball travelling an extra two feet by the time the opponent responds.
Asking people to watch videos of tennis is not the same as playing an actual game of tennis. It might be that professional tennis players can tune out some of the grunts, or that different types of grunts are more or less effective in throwing players off. The other issue is whether or not tennis players are actually aware of the effect that their grunting might be having - if referees believe that players are deliberately trying to hinder their opponents, then penalties can be given.
Or it may simply be that shouting helps players to increase the amount of force with which they can hit the ball. In a 2012 study, US researchers showed that participants who were allowed to produce a “kiap” (a short, controlled yell) before squeezing a handgrip dynamometer improved their handgrip strength, regardless of whether they were an expert or novice athlete.
We are only only just beginning to understand the role that grunting makes in sports like tennis. While these are preliminary studies, they raise interesting questions about whether they should be classed as cheating, or are a legitimate way for players to improve their game. One thing is for certain, though: when it comes to grunting, some players will carry on making a racket.