He goes by the name of Forrest and if you ask him his age he will tell you he is 108.

And if you ask him why he enjoys testing his body on long runs on lonely roadsides he says "when you look like me running along a road not too many people are going to ask you if you want a lift".

But the real reason Garry "Forrest" Preston does up to six major runs a year for charity is he loves to help people, particularly children.

"I try not to tell anybody my real name," he said.

"I just go by Forrest. I have only ever been known as Forrest and that is all I want."

Nothing Forrest does is about him and this long weekend he is participating in the 57 kilometre 4Tracks4Kids walk from Warwick Farm to Rosehill, Canterbury and Randwick where participants will walk down the main straight between races before visiting a Sydney Children's Hospital.

"It is all about helping kids," Forrest said.

The early start and seven hour walk comes just a couple of weeks after the Wollongong ultra-marathon man worked countless hours as a volunteer at the annual Wollongong Relay for Life.

Forrest used to do a lot of his running with Dave Taylor and before there was ever a 24 Hour Man who walked relay for the entire time Forrest actually ran the whole event twice.

"With the first one I did something like 180kms," he said.

"I don't know if I would be silly enough to do that again."

Forrest said he had been interested in doing the 4Tracks4Kids ever since he saw the events founder Richard Calendar do it.

"This is the fifth year," he said.

"This is the first year I have been able to do it."

Asked why he did things like this Forrest said some people were just meant to do certain things and his thing was using his ability for endurance to help others, especially young children.

This weekend he will have to walk though because there is a no running rule with the 4Tracks4Kids event.

The charity event is dedicated in helping children by raising funds to help develop medicines and cures for kid's diseases, training medical personal and purchasing important medical equipment.

But this year it has added meaning.

It is being done in honour of 4Tracks4Kids ambassador Nathan Berry who had just begun a riding contract in Singapore earlier this year when he was struck down by a rare illness called Norse Syndrome.

Subsequently the name has changed slightly in 2014 with the walk affectionately being called A Walk 4 Nathan Supporting 4Tracks4Kids.

"He used to always go to the children's hospital on Christmas Day after buying the kids presents," Forrest said.

"His wife is now the ambassador for this event and I am looking forward to meeting her. To me if you can spend a couple of minutes to make someone smile it is worth millions of dollars and is worth more than anything."

Funds being collected this weekend are being donated to the Sydney Children's Hospital Network, which incorporates both The Children's Hospital at Westmead and the Sydney Children's Hospital in Randwick, the National Jockeys Trust and the Epilepsy Action Australia.