#3 - Slowing down an opponent's reaction time
You might not realise it, but you use sound to gauge how hard your opponent hits the ball, and also the direction of the shot. If they're grunting loudly, and you can’t hear the sound of the ball on the racquet, that affects your ability to judge the shot. Studies have shown that when their opponents are grunting, tennis players are between three and four per cent worse at assessing where the ball is heading and at what speed. One study suggested that players take 30 milliseconds longer to react. That might not sound like much, but in that time the ball has probably travelled around half a meter through the air.
#4 - Confusing an opponent
One devious trick is to let out a huge grunt, as if you've hit an enormous topspin forehand that took a lot of effort, but then throw in a gentle drop-shot. Your opponent won't be expecting that. As Caroline Wozniacki once said: ‘If you grunt really loudly your opponent cannot hear how you hit the ball. Because the grunt is so loud, you think the ball is coming fast and suddenly the ball just goes slowly.’
#5 - Releasing tension
From Andre Agassi to Monica Seles to Maria Sharapova, some of the biggest grunters in tennis history learned the game at the Nick Bollettieri academy in Florida. It's interesting to note that Bollettieri says grunting allows for a "psychological and physiological release of tension".
#6 - Improving breathing and rhythm
Grunting can help with the timing of your shot, with Bollettieri saying the noise “synchronises breathing precisely with hitting the ball”.
#7 - More confidence
Psychologists have suggested that grunting helps a player to feel more assured of themselves on court, which will allow them to produce better tennis.
#8 - Habit – they just can’t help themselves
As a grown woman, Sharapova's grunts have exceeded 100 decibels, which might make her the loudest grunter of all time, though there is no official record. She used to say that grunting was just something she had done since a young age. It was part of her tennis technique. Trying to stop grunting when she was in her twenties would have been as challenging as trying to hold the racquet with a new grip. It was always fascinating, though, to listen to her practice sessions, when she would be completely silent; she only grunted when she was playing matches. Seles has said she grunted from the age of eight, and that she didn't suddenly start as a pro.
#9 - Players copy each other
Just like every other aspect of tennis, younger players look at the elites and want to emulate what they're doing. If grunters are winning Grand Slams, children and teenagers are also going to make some noise. When that generation then reaches the top of the sport, the cycle begins again.