By Megan Lane
BBC News Magazine
At 101 decibels, Wimbledon's defending champion Maria Sharapova is judged the loudest grunter so far. Is it only female players who make a racket on court - and is it tactical?
Sharapova hits police siren volume
It was Monica Seles who originally inspired the "gruntometer", the measuring of decibels on Centre Court by newspapers. The first of the female power players, the Yugoslav teenager's trademark was a loud grunt each time she belted the ball across the net.
Seles registered 93.2 decibels, enough to make her quarter-final opponent at Wimbledon in 1992 demand that she not be allowed to make noise. Seles clammed up - and eventually lost the tournament to Steffi Graf.
Seles would have been a formative influence when today's grunters - Maria Sharapova, Anna Kournikova, the Williams sisters among them - were first honing their skills.
Today grunting among female tennis stars is the norm rather than the exception.
And grunting begets grunting, as quieter players try to out-psyche their opponent, says retiring Wimbledon referee Alan Mills. "A kind of counter-grunt has emerged in recent years whereby offended parties ape their opponent's noises."
At Wimbledon on Tuesday, defending champion Sharapova shattered her own personal record with a grunt of 101.2db - almost as loud as a police siren heard at close-quarters. She, like Seles and other grunters before her, denies that it is a tactical move to put off opponents. It is, they say, simply a natural release of pent-up energy as the ball is hit.
What a racket!
But Mr Mills has told reporters that not only are these grunts deliberate, tennis coaches are teaching women players to grunt the loudest.
Many of those noted for their grunts are the product of Nick Bollettieri's Florida tennis academy, where Seles first yelped her way through training aged 12. Bollettieri said last week that he doesn't encourage his students to make noise: "Never once has that entered into my mind. But I believe releasing your energy is good because if you don't, it tightens up the body."
Monica Seles set the standard
Another rather wishful theory is that the grunt may be an indicator of what the lovely lady is like in bed. During flirtatious banter on Jonathan Ross's chat show last Friday, Serena Williams was playfully teased with repeated recordings of her on-court grunt (she registers almost 90db).
Nor is it only women players. In 1974, Jimmy Connors grunted his way to the first of his two Wimbledon titles.
And when a teenage Andre Agassi played Ivan Lendl in the US Open, the older man complained - without success - about the quite deliberate martial arts-style howls from across the net.
Jimmy Connors, another grunter
Lendl said later that the noise threw his mental game. "When Agassi goes for a big shot, his grunt is much harder, like he thinks it's a winner. If you have a play on the ball, it throws off your timing."
But it didn't stop Lendl winning that match. For tactical reasons or no, sports psychologists say that among world-class players, any advantage gained by distracting an opponent is probably minimal. Those most likely to be annoyed by it are the spectators and commentators.