Sara Armstrong faces an extreme obstacle when she takes on Kokoda Trail

Grenfell's Sarah Armstrong - a member of the Cowra Triathlon Club - loves a challenge.

A two-time triathlon world championship competitor Sarah has set herself a new goal, to take on the Kokoda trail.

Sarah won't be walking to trail, she'll be covering it as a competitor in the Kokoda Ultra Marathon, a three day run, trek, run covering 96 kilometres.

Sarah aptly says she stumbled across the event online.

"I'm not really sure why I'm doing it," Sarah said this week.

"I try not to ever look as something and say that's too hard I couldn't do it.

I try not to ever look as something and say that's to hard I couldn't do it

Sarah Armstrong

"It seemed like it might be fun and I thought to myself, 'There is only one way to find out.'"

Sarah is now just weeks away from finding out how much "fun" the event really is, alongside running mate James Nott.

"I imagine they'll be early morning starts and late afternoon finishes and some extreme weather.

"Apparently it's quite warm and the second night could be quite cold.

"The organisers will put a tent up for us and give us breakfast but other than that we have to carry our own gear, a sleeping bag, clothes and food for during race," Sarah said.

In preparation Sarah has been hitting the trails as often as she can, doing a number of runs in the Blue Mountains in recent months and also locally.

"I've been doing as much training as possible, trail running up Weddin Mountain as often as I can, but it's probably not enough," Sarah admitted.

"I've been out on the trails as much as I can, and as much with a loaded pack as I can." she said.

Day one of the event on July 23 sees the competitors set off from Owers Corner, making their way to Naoro, a distance of 20.3 km with an elevation gain of 1806 metres and a descent of 1406 metres.

On the second day the runners make their way to Templeton's Campsite passing through Brigade Hill and Mission Ridge which was the scene of a bloody and ferocious battle during World War II.

They'll climb 2709 and descend 1782 metres on a day which is described as a trek, not a run.

On the final day Sarah will cover just over 30km and descend a massive 2536 metres after climbing 1003 metres.

After completing the event competitors have be an overnight camp stay in Kokoda that also includes a memorial service at the Kokoda battlefield.