Along with bad line calls and ill-tempered opponents, tennis players have often complained about another irritation of the modern game: grunting.
The loud groans of professional players as they serve or reach for a shot have even been blamed for influencing the results.
Former world champion Martina Navratilova has said that excessive grunting on court is "cheating pure and simple", while Roger Federer, who has won 20 single Grand Slam titles, has called the practice "unsportsmanlike".
Sports psychologists have studied the role of auditory perception in sport to try to discover what impact grunting has on an athlete's performance. It was thought that loud bellowing merely distracted an opponent.
However, scientists from Friedrich Schiller University, in Jena, Germany, have found that very loud grunting leads players to overestimate the length of an opponent's shot. The louder the grunt, the player seemed to reason, the harder the shot.
