One of the best female golfers in the world left an interviewer speechless when she explained why she was undergoing on-course treatment at a tournament in California.

Lydia Ko, ranked number three in the LPGA (Ladies Professional Golf Association), was seen having her back stretched by a physiotherapist during the Palos Verdes Championship.

The treatment led Golf Channel’s Jerry Foltz to ask the New Zealander if she expected it to be a recurring problem for her.

“I hope not,” Ko replied.

“It’s that time of the month. I know the ladies watching are probably like, yeah, I got you.

“So when that happens, my back gets really tight and I’m all twisted up.

“It’s not the first time Chris has seen me twisted, but it got a lot better after he came. So yeah, there you go.”

Foltz looked a little surprised after the 25-year-old’s response and simply replied: ‘Thank you’.

A laughing Ko added, “I know you’re at a loss for words, Jerry. Honesty is.”

The golfer has been praised for her honesty about period pain and the effect it can have on performance.

Ko is number three in the LPGA standings

Menstruation is still something of a taboo in sports, but female athletes are beginning to discuss how it can affect them physically.

In 2015, British tennis player Heather Watson was knocked out of the Australian Open in the first round.

In the post-match interview, she attributed her poor performance to the start of her period.

“I think it’s just one of those things I have, girly stuff,” she said.

In some sports, such as hockey, women’s menstrual cycles are monitored so that training and diet can be adjusted for the duration of their period.