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Psychology

What causes tennis players to scream during a serve?

Quick fact

Grunting masks the sound of the ball hitting the racket strings, which is how players subconsciously judge the ball's speed and spin before it crosses the net.

Why this is interesting

A tennis grunt can reach 120 decibels—louder than a chainsaw—and it gives the hitter a competitive edge by robbing the opponent of crucial reaction time.