You name the distance, and the chances are Penny Purcell has covered it on foot, yet this Anzac Day brings a step into the unknown for the Tauranga race walker.

As the Last Post sounds at dawn across the trans-Tasman, the 54-year-old will take on the 100km Anzac Day Challenge in the heart of Sydney, Australia – walking one kilometre for every year remembered.

Tauranga's Penny Purcell will put her best foot forward by taking on the 100km Anzac Day Challenge in Sydney. Photo: Tracy Hardy.

And with more than 20 years of race walking under her belt, this is a once-in-a-lifetime opportunity that Penny couldn't pass up.

'It is just great,” she says. 'It will be a real challenge and it's going to be good.”

Set in both the Ku-ring-ai and Garigal National Parks, the gruelling one-off timed running and trekking endurance challenge gives participants the opportunity to remember and commemorate Anzac Day, the diggers and their sacrifice, and 100 years of the Anzac spirit.

Under the banner ‘Commemorate, Challenge, Care', funds will also be raised to support injured defence force personnel through the charities Soldier On and Mates4Mates.

And while the event will have a 24-hour time limit, Penny is preparing to push through the pain, aiming to knock the 100km off in about 14 hours – averaging eight minutes per kilometre.

Not much of stickler for training regimes, she heads out for two hours, five times a week, and is confident her base fitness will hold her in good stead, having made 12 consecutive appearances at the annual Masters Games as well as being record-holder for the 67km Great Lake Relay solo female walk.

But like all sports, there is an element of mental toughness needed - something essential in race walking.

'[Walking 100km] by yourself it's quite tough,” she explains. 'I have a radio but it's endurance; you have to concentrate because as soon as you start telling yourself you can't make it, you won't.

'It's a matter of saying to yourself: ‘Yes, I can make it'. You suffer with blisters and you lose your toenails.”

The only thing worrying Penny is the thought of coming across poisonous snakes.

Among the mandatory gear required for the event are compression bandages, in case of an injury or a snakebite, with participants taught how to compress injuries should the issue arise.

'I'm scared of the snakes because we will be walking at night time,” she admits. 'Snakes and spiders will be a bit of a worry.”

The Anzac Day Challenge gets underway in Sydney at 7am tomorrow Australian time.

Send in your Anzac Day photos: SunLive will be commemorating Anzac Day with coverage of events around the region, but we'd love our readers to send in their own photos of the day. Send all Anzac Day photos to: newsroom@thesun.co.nz