Rick Patzold is a numbers man.
The 55-year-old, who lives in Albion Park, Wollongong, will run his 300th marathon in 2020. His 298th will be at The Canberra Times Marathon Festival in April.
But if it wasn't for his mother, Edith Patzold, he wouldn't have run one. Mrs Patzold died from cervical cancer in 1978.
"Mum's date of birth is January 21, 1943, and I'm not religious or anything, but the way I've always looked at that is 21.1 kilometres is a half marathon, and 43 kilometres is my destination," Mr Patzold said.
"If she was born one day before or one day after, I guarantee I wouldn't have run a single marathon."
Mr Patzold began running as a teenager as a way to cope with losing his mother, although it wasn't his passion. Instead, it led him to a decades-long career in rugby league, when one aimless afternoon sprint saw him stumble upon a local sports field.
The closest he came to seriously pursuing running in his teenage years was winning his high school's cross country race in 1977.
"I always remember how enthusiastic mum was when I told her I'd won the race that night - even in her dying days," Mr Patzold said.
"That is still the single most fond memory I have of her."
It wasn't until 2000, when he saw the test event for the inaugural Sydney Marathon was being held, that "something clicked". He wants to run his 50th consecutive Sydney Marathon in 2050.
"There was this mental thing in my brain saying, 'Shit - I'm the same age now as what mum was when she died'," Mr Patzold said.
"That day it sort of clicked into me that I'm going to run a marathon in honour of mum.
"I guess I know I'll run until the day I die."
Mr Patzold said the most significant marathon he has run was the Berlin Marathon in 2016 - a year after his father, Manfred Patzold, died. Both of Mr Patzold's parents were born in Germany.
About 10 metres off the finish line, he performed what he described as a somewhat "outlandish" version of a eulogy. While carrying a portrait of his mother, he threw 42 business cards into the air - each labelled with a message for her - and yelled, "thanks, I love you mum".
"It was the biggest day of my life, probably," Mr Patzold said.
"I get to the 42-kilometre mark of every marathon - which is 42.2 kilometres - so I head off on that special 43rd kilometre, but I never get there because mum is not there.
"I'm running the 43rd kilometre, that's the whole point.
"No pain in any marathon will ever be what I saw mum go through."
This year will be Mr Patzold's 19th consecutive The Canberra Times Marathon Festival. He has run the seventh most marathons of any Australian, and the most marathons of any Australian under four hours.
- The Canberra Times Marathon Festival presented by Tata Consultancy Services is on from April 4 to 5. Events include 5km, 10km, half marathon, marathon and ultra marathon distances.
- Register at events.solemotive.com/canberra-times-marathon-festival