So the Thirroul real estate agent will take matters into her own hands when she completes the endurance test in Huskisson on Sunday.

Johnston's journey started earlier this year when she was handed entry into the New York Marathon.

That was before COVID-19 brought the world to a grinding halt.

Already in training and determined to complete a race, Johnston looked closer to home and signed up for the Sydney marathon.

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Joining her at this point in the process was close friend Ellie White.

The Sydney race was originally scheduled for this Sunday. It was first postponed, then cancelled altogether.

So Johnston and White will travel down to Huskisson and run the 42.2 kilometres on their own.

"I was registered to run in the New York Marathon," Johnston said. "That was cancelled, so then I was signed up for the Blackmores in Sydney. That was pushed back then also cancelled.

"So we thought, 'right, let's do our own, just the two of us.' We've both been motivating each other and we've been training since the start of the year, so if we're not ready now, we'll never be."

Driving Johnston throughout this journey has been a desire to raise money for charity.

The pair have set up a GoFundMe and hope to generate $5000 in donations for the Humpty Dumpty Foundation, an organisation that provides essential medical equipment for sick and injured children.

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The charity holds meaning for both runners, with some of Johnston's friends raising sick children, while White, a paramedic, regularly treats youngsters battling illness.

"I've always said if I run a marathon I'm going to do it for a cause. Having them on board has given us that motivation to go out and smash it.

"Being a mum and associated with kids you're always grateful having healthy kids, I've got friends with children who have had cancer.

"Ellie as a paramedic sees first hand the need for equipment and the lack of it. If we can run towards that, it's something close to both our hearts."

The pair have been working hard over the past six months, with plenty of running and strength sessions with their personal trainer to ensure they can finish the gruelling test on Sunday.

Having completed Tough Mudders and run a half marathon in previous years, physical challenges are not a foreign concept.

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This, however, will be the toughest of the bunch. But when the pain starts to build, there will be one thing that motivates Johnston and White to reach the finish line.

"We're representing something important. These guys help provide vital medical equipment specifically for children. Wollongong and Shellharbour hospitals benefit from the charity.

"It's good to have something motivating us instead of personal gratification. We have a reason to complete this race, we can help other people."

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