The 62-year-old is legally blind, with bilateral optic atrophy since birth, although after 51 marathons on six continents that has hardly been a barrier before.

In August 2011, his knee packed it in while preparing for a half marathon, and the response was a procedure where the bone in the leg is cut, straightened and has a plate put on it, transferring the weight from "the bad side to the good side", as he puts it. He has run two marathons since the six-month recovery.

But perhaps most impressively, Sunday's marathon - Mr Arthur's 18th - comes only two weeks after he completed the Antarctica marathon on King George Island in sub-zero conditions.

"It was minus five and stayed at minus five and actually probably got a little bit colder during the marathon, and it had been wet so there was a lot of mud turned to ice, and steep sections in the shade were very treacherous: I slipped four times during the race," he says.

"Unless things go very badly wrong, this one this coming Sunday will be quicker but I'll probably be a lot tireder at the end of it."

In addition to a flatter track and better footing, the Watson resident says he will be looking forward to catching up with some familiar faces.

"There is a good camaraderie, you tend to go to similar marathons," he says.

The banter and chat doesn't last the whole distance however.

"As things get serious from 21 kilometres, things go quiet and everyone focuses on the job at hand," he says.

Mr Arthur, who moved to Canberra from Wagga Wagga two years ago, says Diane, his wife of 39 years, has been a great support during his marathon career, with the couple enjoying some of the world's more unusual running locations. "She's seen some good places: we've travelled to South Africa and been on a game reserve for a marathon, run on the Great Wall of China, been to London, and visited friends in America and there happened to be a marathon in their town so we ran that one," he says.

There is at least one more international running trip to come, with Mr Arthur looking towards an event in Chile next year to complete his mission of running a marathon on each continent.

In addition to taking him a step closer to being a Burley Griffin - the title given to the 15 men who have already completed 20 Canberra marathons - this year Mr Arthur is raising money for prostate cancer, after scares last year.

"Luckily for me it wasn't [cancer], at the same time a very close friend of mine had a very close miss with prostate cancer … and at the moment is supposed to be in remission," he says.

"It [has] made me aware that people of a certain age need to get the tests done, both the blood test and the physical test.

"Prevention is better than cure.''

Entries for The Canberra Times Canberra Marathon, half-marathon and ultra-marathon have closed, but places are still available in the 5 and 10 kilometre events. Entry is online only and closes on Friday.