The face of the Sydney Marathon is changing.

The picturesque road race that crosses the Harbour Bridge and loops around to finish at the Opera House is in a battle against the Cape Town event and another in Chengdu, China to be added to the list of the World Marathon Majors.

Despite being the youngest Australian marathon behind Canberra, Melbourne and Brisbane, Sydney, in only its 25th year, could be set to join the status of elite marathons in New York City, Chicago, Boston, London, Berlin and Tokyo.

A less publicised change ahead of Sunday's anticipated race is an initiative from the Sydney Marathon's new naming rights sponsor about "supporting a culture of running across Indigenous Australia".

TCS, a global leader in IT services, consulting and business solutions, has already been a long-standing partner for Australia's Indigenous Marathon Foundation and the multinational company out of India plans to "focus on attracting more Indigenous runners to participate" in the event.

Wiradjuri woman Hayley Pymont, an IMF graduate in 2022, was named the first Indigenous Running Ambassador of the Sydney Marathon to embrace that change.

The 29-year-old from Wollongong epitomises the background of most interested Indigenous participants in Robert de Castella's marathon project.

"I have actually only been running since 2022 when I was first selected to be a part of the Indigenous Marathon Project," she told the Sydney Marathon website in a Q&A interview.

"Before that, the furthest I had run was roughly 14 kilometres, but I have always liked soccer and athletics.

"I didn't ever think I'd be a long-distance runner – it's pretty wild."

But that has changed quicker than she thought with working hard but also the commonsense to "listen to her body and know when to actually rest".

After running her first 42.195km distance through the boroughs of New York nearly two years earlier, Pymont said the experience has had a profound effect on her life.

Overcoming an injury of sorts before stepping behind the start line has only strengthened her resolve further.

"I prepped pretty well, and I was feeling good going into it until I rolled my ankle two weeks before the race," she said.

"I love a challenge, but the injury put me in a bad position on the day. And then it was a bit of a heat wave as well.

"So, I was gone pretty early, even from like the 15km mark.

"From there, I physically hit the wall, and it was tough.

"The atmosphere of everyone around me kept me going."

The self-belief arising from the setback reinforced a turnaround from a complete novice runner to accomplished runner from the training of the Indigenous Marathon Project where it started from scratch and was conducted inside only six months, leading Pymont to call 2022 one "special year".

"Honestly, it was amazing, but very challenging," Pymont said.

"Obviously, going from someone who has barely (been) a runner to training for a marathon in six months is pretty crazy."

Pymont looks at the process of running vastly differently now, saying pounding the asphalt kilometre after kilometre is less about physically challenging her body than it is her head.

"I love running, but I keep doing it because of the benefits to my mental health," she said.

"Like, some days it feels really good and I'm feeling on top of the world. And then some days it's really hard to even get out the door for a run.

"But I think, actually, that those are the more important runs – when you're struggling, and you get out there and get it done anyway."

So much so that Pymont will attempt to pull off another more extraordinary challenge.

At the end of the year, she will be running in her first ultra-marathon to raise money for an unnamed Illawarra charity.

She has only completed three marathons to date, including races on the Gold Coast and in Berlin.

Ultra-marathons is another level as having no set distance, but can run for up to 100 kilometres.

"I guess one of the best things to come out of all of this is a passion to push my limits and to continue thriving," Pymont said.

Pymont will run a light 10 kilometres in Sydney at the weekend in one of the alternative races so she can "support the marathon runners coming through and just help where I can".

But she is potentially looking at running the London Marathon next year instead of Sydney due to her ambassadorial role.

She has already inspired her local Dharawal Runners and Walkers group, where many participants under 30 years of age are looking to follow in Pymont's footsteps and apply to join the Indigenous Marathon Foundation.

When the Indigenous followers ask Pymont how to run out a daunting marathon, she keeps the advice pretty simple.

"Just to trust your training and back yourself," she said.

"It's going to be hard out there, but just keep going.

"And while there's thousands of people around you running the same event, you just need to focus on yourself and have fun.

"Embrace the experience."