Tennis players grunt, groan, and shriek during matches because forceful exhaling during a stroke measurably increases the speed and power of the shot. Research in the Journal of Strength and Conditioning Research found that both ball velocity and muscle activation are significantly greater when players vocalize at the moment of contact. But power isn’t the only reason. Grunting also helps players manage their breathing under intense physical demand, and it may give them a subtle edge by disrupting their opponent’s ability to read the ball.
Grunting Makes the Ball Travel Faster
The simplest explanation is also the most well-supported: grunting produces harder shots. A study of collegiate tennis players found that serve and forehand velocities were significantly higher when players grunted compared to when they stayed silent. A separate study at the University of Montana measured a 3.8% increase in ball speed during grunting conditions. That may sound modest, but at the professional level, where margins are razor-thin, an extra few kilometers per hour on a serve or forehand can be the difference between a winner and a ball that gets returned.
The mechanism comes down to core engagement. When you vocalize forcefully, you’re performing a powerful exhale that activates your trunk muscles more intensely than a quiet breath would. Researchers found that peak muscle activity in the external obliques and chest muscles was significantly greater during grunting strokes. These are the same muscles responsible for generating rotational force in a serve or groundstroke, so recruiting them more effectively translates directly into a faster swing.
How Breathing Works During a Tennis Stroke
Tennis creates a unique breathing challenge that doesn’t exist in sports like running or cycling. In those activities, athletes naturally sync their breathing to a steady rhythm of footsteps or pedal strokes. Tennis doesn’t allow that. Players sprint, stop, rotate explosively, and hit the ball, all within a couple of seconds, then do it again from a different position on the court.
Research published in the European Journal of Sport Science found that about two-thirds of tennis players briefly hold their breath for roughly half a second around the moment they strike the ball, especially on harder shots. This is essentially a mini version of the Valsalva maneuver, the same pressurized exhale you’d use when lifting something heavy. The breath hold stabilizes the torso, but it needs to be released. The grunt is that release. Without it, players risk holding tension in their chest and abdomen longer than necessary, which can disrupt their recovery breathing between shots and lead to premature fatigue.
For many players, the vocalization becomes an automatic part of their stroke rhythm, timed precisely to the point of contact. It ensures they exhale rather than holding their breath through the entire swing, keeping their breathing cycle moving even during the most explosive efforts.
The Distraction Factor
Not everyone buys that grunting is purely physical. Former champion Martina Navratilova publicly accused players like Maria Sharapova and Michelle Larcher de Brito in 2009 of using their vocalizations to deliberately distract opponents. The accusation isn’t baseless from a perceptual standpoint. The sound of a racket hitting a ball carries information about spin, speed, and direction. A loud grunt at the exact moment of contact could theoretically mask those acoustic cues, giving the opponent slightly less information to work with.
The International Tennis Federation acknowledges this possibility. Rule 26 explicitly states that purposeful and excessive grunting constitutes a hindrance and can result in a point penalty. In practice, though, the rule is rarely enforced, partly because it’s nearly impossible to determine whether a player’s vocalization is involuntary or strategic. Most players who grunt loudly have done so since childhood, and the habit is deeply embedded in their stroke mechanics.
Where the Habit Comes From
Male players have been grunting in professional tennis since at least the 1970s. Jimmy Connors was a notable grunter at the 1974 Wimbledon Championships, and Andre Agassi continued the trend through the 1980s. But the public conversation around grunting exploded in 1992, when Monica Seles made her first appearance at Wimbledon. British newspapers started measuring the decibel levels of players’ grunts, publishing the results on a so-called “grunt-o-meter.” Seles became one of the first female players widely associated with loud on-court vocalizations, and her success made it clear that grunting wasn’t going away.
Since then, players like Sharapova and Serena Williams have become synonymous with audible exhalation during matches. Many coaches now teach forced exhaling as a standard part of stroke technique from a young age. For players who learn this way, grunting feels as natural as the follow-through of their swing. Asking them to stop would be like asking a weightlifter to breathe silently during a deadlift: technically possible, but likely to reduce their output.
Why Some Players Are Louder Than Others
The volume and character of a player’s grunt varies enormously. Some players produce a short, sharp exhale barely audible above the crowd noise. Others sustain a vocalization that lasts well after contact. The difference comes down to individual breathing habits, stroke mechanics, and how forcefully a player contracts their core on each shot. Players who hit with extreme topspin or generate power primarily through trunk rotation tend to vocalize more, because those strokes demand greater core engagement.
There’s also a learned component. Players who started grunting early in their development often escalate the volume over years of competition without realizing it. The vocalization becomes part of their proprioceptive feedback loop, a signal their body uses to confirm timing and effort. Stripping it away can feel disorienting, which is one reason attempts to regulate grunting have gained little traction despite periodic complaints from fans and fellow competitors.