On October 1, the 56-year-old grandmother will be running 250kilometres from Echuca to Altona North to raise money for the Royal Children’s Hospital’s neurology unit in honour of Luke, who died from an undiagnosed brain tumour 10 years ago.

Luke had been in hospital receiving treatment for gastroenteritis when he ‘‘crashed’’.

‘‘It had not been gastro; it had been a brain tumour, which had gone all the way around and then exploded,’’ Ms Byrne said.

‘‘They kept him on life support until [his] mum and dad had come to the realisation that he’d really gone.’’

She said it was five days before Luke’s life support was switched off.

‘‘I was holding Luke. Between me and his other grandma we just stayed with him and sang lullabies until he had gone,’’ Ms Byrne said.

‘‘Prior to that happening, I’d always seen myself as a very weak person who needed someone to guide me all the time and get me through.

‘‘Then I discovered that I was the one who had realised there was no hope for Luke and I had to get his mum and dad to see it and organise that and then organise the funeral...

‘‘I helped bathe him and get him ready. That was something I never thought I could do.

‘‘I did the eulogy and I got through all that before being able to collapse and going into my little cocoon. That’s when I realised I could stand on my own two feet. That was Luke’s little lesson for me.’’

Ms Byrne, who has since become a personal trainer, said she was obese before joining BayFit Leisure Centre’s Biggest Loser program.

When she started running, she did the ‘Cliff Young shuffle’ — a cross between a run and a walk made famous by potato farmer Cliff Young, who won the Westfield Sydney to Melbourne Ultra Marathon at age 61.

‘‘That’s who I reminded myself of,’’ Ms Byrne said. ‘‘And I said, he did wonderful things when he got older; could I do much the same?

‘‘We’ve set up, with the Royal Children’s Hospital, a charity foundation called Luke’s Run, so people can go directly online and donate to the fund.’’

All donations go to the RCH’s neurology department.

Ms Byrne will leave Echuca on October 1 and is expected to finish at BayFit Leisure Centre in Altona North on October 16.

The community has been invited to cheer her on as she runs through Ascot Vale, Footscray, Newport and Altona North.

Details: www.runforluke.wordpress.com