The chair umpire can penalize a player for ''hindrance,'' but the rule is rarely enforced for grunting. The hindrance rule states: ''If a player is hindered in playing the point by a deliberate act of the opponent, the player shall win the point.''
Serena Williams lost a point when she shouted before Samantha Stosur struck the ball during the final of the 2011 US Open. At this year's French Open, the chair umpire twice awarded a point to Williams because of her opponent's grunting.
Brad Gilbert, a tennis commentator and former coach of Andre Agassi, says if players start losing points, it will stop.
Grunts, shrieks and hoots
That's what fans can look forward to next week at the US Open, where earplugs will be optional while watching some of the world's top players, such as noted men's grunter Novak Djokovic.
On the women's side, the high-pitched shrieks get the most attention. The WTA in June announced plans to educate young players and coaches to keep the decibels down. There's also been talk about chair umpires using a hand-held ''grunt-o-meter'' — not unlike a radar gun on serves.
Opponents say it's unfair because the noisemakers make it hard to hear when a ball hits the racket. Players also can be penalized under the hindrance rule, if the chair umpires believe it's deliberate and creates an advantage.
Here's a look at offenders past and present — and how to tame the grunters.
— The Associated Press
Top-ranked Victoria Azarenka (right) hoots with nearly every point, using an ''AH-OOOOOH'' sound that extends well past the point of contact with the ball. Maria Sharapova (left) employs a high-octave shriek that reaches aria heights late in tight matches. The Williams sisters' decibel levels tend to rise with important points.
On the men's side, Novak Djokovic and Rafael Nadal grunt with their groundstrokes, but as Billie Jean King points out, ''It's a lower grunt. Everyone seems to be OK with that. It's the pitch of the grunt that bothers (fans).''
Among the quietest players? Effortless Roger Federer.
Growth of the grunt
Teenager Monica Seles took the modern grunt to new levels in the early 1990s, using two-note ''AH-HEEE'' shrieks to accompany her two-handed shots on both wings. Her memoir noted she started tennis at age 6 and grunted from Day 1 because she was so small and wanted to put every ounce of energy into the ball.
The grunt apparently worked for Seles, who reached No. 1 at 17 and won eight majors by 19. In 1992, Wimbledon officials asked her to quiet down after Martina Navratilova complained she couldn't hear the ball hit the racket. Seles followed in the guttural footsteps of Jimmy Connors, who provided yells and fist pumps during his spectacular run to the semifinals of the 1991 US Open at age 39.
How big an issue?
The issue isn't particularly player-driven, with few complaints over the years to chair umpires. Chris Evert calls the cacophony annoying, but she believes the criticism is more fan- and media-driven.
Former No. 1 Caroline Wozniacki (right) has said some players ''do it on purpose.'' Agnieszka Radwanska (left) considered the grunts too loud at this year's Australian Open, where the crowd started imitating Victoria Azarenka's hoots. When Azarenka and Maria Sharapova faced off for the title Down Under, local papers called it the ''Scream Queen Final.''
Fans also echoed Sharapova's grunts when she hit the ball during a 2008 Fed Cup match in Israel.