PARIS — Why would some Olympic surfers wear helmets during the Paris Games?

Well, now we know.

Johanne Defay of France needed four stiches for a head wound Saturday, underscoring the danger of surfing at the famous Teahupo’o break in Tahiti. It’s not just the powerful wave. It’s the shallow, sharp coral reef.

No helmet, no mercy.

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"Yesterday on my first wave I had a fall," Defay said. "It just went so big, I went straight into the coral with my head, I had four stitches.

"They made me go through the concussion protocols and the results were so-so, so they made me go through them all again this morning. … There’s no trauma, so we’re happy."

Before the Olympics started, American surfer Griffin Colapinto told USA TODAY he’d experimented with wearing a helmet during practice sessions at Teahupo’o. He said thought the equipment would be a common sight when the Games began.

This article originally appeared on USA TODAY: Olympic surfer gets four stitches after hitting head on coral reef