Ms Parker, 44, meets fellow riders Rebecca Brown, 54, and Leanne Aust, 48, four times a week. The women ride about 220km a week.

''When I first started the other two would always like to ride behind me so that they could see me come off, but I think I've kind of mastered it now,'' Ms Parker said.

''But look, being clipped on to the bike is something you've got to get used to; going over all sorts of different terrains is something you've got to get used to [because] you've got sand, rocks, gravel, road, grass.''

Ms Parker's next challenge is slightly more ambitious than not falling off her bike: a 1000km, 25-day cycling tour with Ms Brown and Ms Aust through the Tibetan Plateau, from Lhasa to Kathmandu. They will depart on September 20.

After Canberra's hills, cycling on dirt roads and over five passes higher than 5000m and headwinds not to mention the chance of altitude sickness would be daunting to anyone.

But the women feel up to it.

Ms Parker said, ''Exercise on a continual basis, like all day every day, is going to be a challenge for my body. Mentally it will also be challenging, having to get up every day and just on the bike but you can't make excuses: you just have to do it.''

Ms Aust agrees. ''One thing about people, particularly at our age, is you tend to underestimate what you're capable of doing until you actually start trying these things and find, 'Well, hey I can do it.'

''And I think my philosophy is you've got to do it while you can.

'' We've all lost people to things like cancer and seen people with really bad injuries that end their sporting careers and if you've got an opportunity to do something like this, why not? Just do it.''

Ms Aust said she loved that part of the world. ''The Tibetan Plateau is fairly stark but beautiful in a way because it's such a remote part of the world.

''When I've been trekking I've seen those mountains from the Indian and the Bhutanese side but I'll be seeing those same mountains from the Tibetan side, which will really be special.''

Ms Brown was looking forward to reaching Everest Base Camp, and the two days of riding from Thang La in Tibet to Kathmandu.

''It's a downhill 160km and there'll be a lot of work to get to there, so I'm looking forward to the challenge and the adventure.''