Why do women tennis players grunt so noisily?

[Howlin Mad Missy]

it's related to the whole exhale on effort, like some martial artists/boxers snort when they punch but with tennis it's not just when the ball hits string, you follow through the stroke with the racket head, hence the prolonged grunts No need for it really, it's how they've been coached.

[AdamGB]

It's totally disproportional to the exertion they're actually making.

Bums on seats I suppose.