The sound of a stroke
A tennis grunt can accompany a forceful breath out as a player hits the ball. It is linked to the effort of the stroke, and studies suggest it can help some players produce force. That does not mean every player needs to shout, or that every grunt has the same purpose.
Listen to a rally and the sound often arrives with the swing. To understand what it might do, researchers have compared strokes under different breathing conditions.
What the experiments found
In a 2014 study of 32 college tennis players, serves and forehands were faster when the participants grunted than when they did not. The researchers also measured greater force and activity in the muscles they tested.
That was a controlled comparison in a small group, rather than proof that a louder grunt wins more matches. It does not tell us why any particular professional makes a particular sound.
Is the noise essential?
A 2016 study compared grunting with other breathing conditions during a simulated forehand. The authors concluded that a quieter, forceful breath out could also be used to support force production.
That distinction matters: the breath and the noise are related, but the loudness itself is not a proven requirement for a good shot. The study tested a held pushing action, not a full match, so its results should stay within that setting.
When sound becomes a hindrance
Sound does not give a player permission to interfere with an opponent. Under ITF rule 26 on hindrance, a player who is hindered by an opponent’s deliberate act wins the point. An unintentional hindrance can instead lead to the point being replayed.
The key issue is hindrance, not simply whether the match is noisy. Rule 26 addresses interference rather than setting a decibel limit.
For the rest of what you hear between rallies, explore how tennis scoring works. Or discover why players keep changing ends.