Like most people running in The Canberra Times running festival, Peter Granleese will worry about getting puffed out, climbing too many hills or suffering a stitch.
But unlike most, he will also rely on a verbal guide to describe the track, warn of hanging branches and alert him to turns.
The determined runner was born with roughly two per cent eyesight – a condition that deteriorated with age.
He found newfound confidence when he joined the Canberra chapter of Achilles International Australia, which helps people who are blind, vision impaired, or have a physical disability, enjoy the perks of running.
"I've enjoyed it very much," he said.
"As a blind or vision impaired person, like may people in my situation, we live pretty isolated lives and don't have the same opportunities as other people.
"It has given another social dimension to my life and has made me much fitter, although it's a big challenge for me to do the 10 kilometre race."
While Mr Granleese runs with a sighted guide, Peter Ralston, who started Canberra chapter of Achilles with his wife Marilyn, and Paralympic Gold medalist Lindy Hou, will also be taking part.
Impressively, it will be the seventh marathon Mr Ralston will have completed in three years.
His new goal is to help one of the 15 Canberra Achilles members with a disability run a marathon, hopefully overseas.
"I can see a day when we would be able to send a person to a New York marathon, or maybe they could end up at Rio," he said.
"We always encourage them to do the fun runs because it helps break down barriers when they are out there in the community running with other people without disabilities."
Through meeting three days a week and running various tracks around Canberra, he's seen people overcome many obstacles.
"One lady has graduated to running 10 kilometres, when she was unable to run a complete 5 kilometres to start with.
"And they always have a great sense of humour."
Volunteers are also trained for running festivals to ensure they can run slightly faster than the runner who is blind. There are also technical skills involved in using the tether and in understanding how to best describe the environment.
Mr Ralston is always looking for more members and volunteers to join the club. For information, visit achilles-sydney.org.au/canberra.html