Last weekend she let the lawn go and won a 240km ultramarathon instead. In record time.

The Coast to Kosciuszko ultramarathon - which she completed in 32 hours and 31 minutes - was a goal Muston wanted to achieve before her 50th birthday.

And the super-human effort appeared to have taken little toll on the 49-year-old mum yesterday.

Muston was back at work at the Australian Taxation Office in Civic looking fresh and relaxed.

''I never normally take a day off after racing, so I didn't really consider it,'' she said. ''I just thought the concept of running from the beach, where you can start with your feet in the sand, and then run to the highest point of Australia, it just sounded like an amazing thing to do.''

''Then when I made it to the finish, I just couldn't believe it really, that 30 hours ago I'd been by the sand and got there on the power of my own two legs.''

While she has been running for more than 30 years and competes in six or seven marathons each year, this was the longest distance Muston had ever attempted at once.

And yet she hit the finishing line after slicing nine hours off the race record.

Muston had completed only one 100km race to qualify for the Coast to Kosciuszko and race director Paul Every didn't even think she would be a contender.

For more details of the race and Muston's achievement, see today's Canberra Times.