'Stir crazy' McKeown breaks 100m backstroke short-course world record

A "stir-crazy" Kaylee McKeown smashed the women's 100m short-course backstroke world record after a last-minute decision to enter the Australian championships following her Olympic heroics.

Just weeks ago, the 23-year-old completed the Olympic long-course backstroke double in Paris, winning both the 100m and 200m gold medals.

It matched her exploits from the 2020 Tokyo Olympics.

While many of her contemporaries are resting, McKeown said she was bored sitting at home and decided to enter the Australian short-course championships in Adelaide on a whim.

It paid off with a new world record of 54.56 seconds on Thursday evening, bettering the previous best set in 2019 by fellow Australian Minna Atherton.

"I was going a bit stir crazy, sitting at home, so decided to jump back in (the pool) two-and-a-bit weeks ago, and just increasing the sessions," she said.

"I don't mean to toot my own horn but we're doing some pretty incredible stuff at training."

McKeown had already qualified for the December world short-course championships in Budapest courtesy of her Olympic victories, but said she was undecided whether to swim in Hungary.

"I'll see how I feel after World Cups (in October-November) ... and see if I want to do world short-course in December. But I'm not putting any pressure on myself," she said.

McKeown is also 200m backstroke short-course world record holder and will race the event in Adelaide.