Why Do Tennis Players Grunt? The Science Behind Tennis's Loudest Habit

Turn on a match at Wimbledon or the US Open with your eyes shut and you will still know exactly when the ball is struck. That rising eeee-UHH has become as much a part of professional tennis as the thwack of strings and the umpire's call of "quiet, please". Some fans find it thrilling. Others reach for the mute button. Almost everyone, at some point, has wondered the same thing: why do tennis players grunt at all?

It turns out the noise is not just theatre. There is real physiology behind it, a surprising amount of research, and a history longer than most people assume.

So why do tennis players grunt when they hit the ball?

At the simplest level, a grunt is just a forceful exhale timed to the moment of contact. Watch a weightlifter drive up from a squat, a boxer throw a punch or a martial artist snap out a strike, and you will hear the same thing. Breathing out hard braces the core, stiffens the trunk for a split second and gives the body a stable base to swing from. A tennis stroke is an explosive, whole-body effort, so a sharp exhale is a natural by-product rather than an affectation.

The grunt also helps with rhythm and timing. Groundstrokes are built on a chain of movements that runs from the legs, through the hips and trunk, out along the arm and into the racket head. Coaches call it the kinetic chain, and it sits at the heart of a repeatable groundstroke, as we cover in our five steps to a cleaner forehand. Exhaling on contact gives a consistent audible cue that the swing has fired in the right order, which is why many players do it without ever being taught.

Does grunting actually add power?

This is where the science gets interesting. A 2014 study of collegiate players, published in the Journal of Strength and Conditioning Research, measured serve and forehand speeds with and without grunting. The players hit roughly five per cent faster when they grunted. Five per cent may not sound dramatic, but on a serve already travelling well over 100 mph, it is the difference between comfortably returnable and genuinely awkward.

Two things are worth keeping in perspective. First, the grunt is not the engine; it is a small amplifier bolted onto good technique. The real power comes from the ground up through that kinetic chain, and from the frame you swing. A racket that genuinely suits your style will do more for your pace than any amount of noise, which is exactly why it pays to spend time on choosing a racket that suits your game. Second, the same study found that all that extra effort did not raise the players' oxygen cost, so the grunt appears to be a low-price way of squeezing out a few free miles per hour.

Club players chasing more pace often blame their arm when the answer is lower down the chain, or in their kit. If your shots feel heavy and slow no matter how hard you swing, it is worth reading why your strings might be holding you back, because the strings do more of the work than most people realise.

Can a grunt put your opponent off?

Possibly, and this is the more controversial part. A well-known 2010 study by researchers Scott Sinnett and Alan Kingstone asked people to judge which way a tennis ball was heading, sometimes with a burst of sound played at the moment of the hit. When the sound was present, participants were both slower and more error-prone. The delay was small, around 30 milliseconds, but the researchers pointed out that in that fraction of a second a fast ball travels roughly an extra two feet. At the top level, two feet is the margin between a clean return and a stretch you never quite reach.

That has fuelled a long-running argument that loud grunting is, whether players intend it or not, a form of gamesmanship, which is why the sound divides opinion so sharply. Supporters see a natural expression of effort; critics see an unfair edge dressed up as breathing.

When did tennis players start grunting, and who did it first?

Grunting feels like a modern habit, but it is older than the current generation. Jimmy Connors, one of the fiercest competitors of the 1970s, is often named as the earliest prominent grunter, audible at Wimbledon as far back as 1974. Andre Agassi carried the trait into the 1980s. On the women's side, Monica Seles became the player most associated with grunting in the early 1990s, and her run to the 1992 Wimbledon final put the sound firmly in the spotlight.

What changed since then is volume, in both senses. As the game got more physical and equipment let players swing faster, the grunts grew louder and more frequent, until they became a defining feature of the modern tour.

Why do female tennis players grunt so much?

This is one of the most searched questions on the topic, and the premise is a little unfair. Plenty of men grunt loudly too; Rafael Nadal and Novak Djokovic are hardly silent. The stereotype took hold largely because a handful of the very loudest players happened to be women, and their matches drew enormous attention.

The decibel records tell the story. British newspapers even ran a "grunt-o-meter" from the early 1990s to measure the shrieks. Monica Seles was clocked at around 93 decibels in 1992, and Maria Sharapova reached about 101 decibels, roughly the level of a passing motorbike. The record is usually credited to Michelle Larcher de Brito at around 109 decibels at the 2009 French Open, comfortably louder than a chainsaw. Those headline numbers, far more than any real difference between the men's and women's games, are why the question gets asked at all.

Is grunting against the rules?

Not directly. Tennis has no rule that sets a maximum volume for a grunt. What it does have is a "hindrance" rule, which lets an umpire penalise a player for deliberately distracting an opponent. That rule is rarely invoked for grunting, but it can be: at Wimbledon in 2023, Novak Djokovic was docked a point for an extended grunt after a shot. The women's tour has also explored handheld devices to measure grunting, with a view to gently discouraging it in younger players coming through. For now, though, the grunt is here to stay, tolerated as part of the sport's soundtrack.

Should you grunt at your club?

If it happens naturally, there is no reason to fight it. A relaxed exhale on contact can help you time the stroke, stay loose and avoid the classic amateur habit of holding your breath through the point. The trick is simply to let the breath out, not to manufacture a theatrical shriek to unsettle the person across the net.

More than anything, the grunt is a reminder that tennis is a game of explosive, full-body effort, which is a large part of why it is so satisfying to play. If reading about all this has you itching to get back on court, these reasons to take up the game are a good place to start. Grunt optional.