The 24-year-old has already spent one stint at altitude and will travel back to Park City on Thursday for a second three-week block.

Hull isn't the only athlete to use the thin air to her advantage, sports stars long basing themselves in mountainous areas ahead of major championships.

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The former Kembla Joggers member said the benefits of her first Utah camp became clear upon returning to Portland and she's hoping another three weeks will provide the fitness needed for an impressive Tokyo Olympics.

"This is the first time I've done real altitude," Hull told the Mercury from the US. "Sleeping at an elevation of 2500 metres, you have to sleep that high to get the full physiological effect.

"Being back in the Pacific North-West, the air is so fresh, the humidity is different, I noticed it as soon as I got off the plane. Waking up that next morning, I went out for a run and couldn't believe how much better I felt.

"I've had 10 days training down here now and seeing the times I can hit, it pays off. You don't just feel yourself getting physically fitter but you can feel yourself getting mentally stronger. It's not easy running that terrain in Park City. There's no easy run, everything's challenging and you really have to approach it differently."

After spending much of 2020 in the Illawarra due to coronavirus, Hull returned to her US base earlier this year.

Racing opportunities have been limited of late, however she will have the chance to see how she's placed in a 1500 metres race in McKenzie River on Wednesday (AEST), athletes raising money to help the region recover from recent bushfires.

With the top Americans currently contesting their Olympic Trials, Hull is looking to hit the front early and control the action when she steps on to the track.

"It's going to be a different race to the only other 1500 I've done this year. It won't be as crowded as the race I ran in LA so I want to practice doing something different, doing a lot of work from a long way out, it's not a way I've run for a long time.

"It will be good to not think about pace and just go for it from a fair way out. The goal for [coach Pete Julian] and I, first to run hard, but to try and put myself as close to four minutes as possible. Knowing the next 1500 I run in a month, I'll be trying to go under that four-minute barrier I want to get as close as possible in this race."

The current Australian 5000m record holder and former 1500m record holder, Hull has qualified in both events for Tokyo.

Choosing which race to contest at the Games has proven a difficult task, the Albion Park Little Athletics product changing her preference on a regular basis.

With a deadline now looming, a decision will be made following this week's race, and Hull said whichever event she chooses, her expectations will be high.

"It changes every time I do a specific workout. We'll know after this 1500, we'll take the emotion out of it, take 48 hours to decide and from there I'll know a month out which event.

"I look at the world rankings and I have similar expectations for both events. I definitely want to make the final, I want to be an Olympic finalist and that will be a big step towards what I'm trying to do in 2024 and 2028."