Team Death Cheetahs wouldn't miss it for the world.
Dad Mark Colthart and twins Charlie and Max (10) return to race the short course series this year. They feel the extreme nature of running off-road in winter is a large part of the fun.
"Whether it's Max rocking out to his favourite tunes at Woodhill, me piggy-backing our 6-year-old daughter Lucie up the hills at Shakespear, or Charlie whooping through the mud at Riverhead yelling 'Mum would hate this!' It's the stuff memories are made of," said Colthart.
Xterra is comprised of seven off-road run/walk events that can be entered as a series or individually. Each event is held at a different location within the greater Auckland area.
The courses are very different and designed to showcase each location's natural environment - from Shakespear Regional Park coastal rock-hopping, to Riverhead Forest puddle-jumping, and Hunua Ranges' sublime native bush.
There are four distance options ranging from a 6km short course to a 20+km super-long course. The range of options mean families with older children who want a degree of independence and outdoor adventure can participate within the safety of an organised event.
Among those who explore all options Xterra has to offer are the Smithwood family - familiar faces on the circuit. Daniel Smithwood was a top competitor over the longer courses for a number of years before children arrived.
"Before children there was endless time to sleep, train and race," he said. "With three sons it's sometimes an achievement to put my shoes on and get out of the house once a month."
A growing family has not dented Smithwood's enthusiasm to get to the events, however.
"Initially my youngest boys enjoyed the creche while I ran, but last year Jackson [5] completed four short courses with me. We even managed to get around the Riverhead mud-monster with 2-year-old Blake in a backpack."
In the past Xterra has been a full family event for the Thomsons, with twins Claire and Ashley often battling for the win over the mid-course while mum and dad ran a variety of mid- to super-long courses.
Similarly, the Paul family - newcomers to the trail-running scene - find there is something to keep everyone happy every third Sunday. Dad Gregor runs the super-long course; older siblings Mackenzie (11) and Isla (9) race the short 6km course and mum Fiona and youngest son Lachlan tackle the short course at a less intense pace.
Fiona laughs: "The first time we ran at Shakespear I brought along sweets to jolly the kids along, but I didn't even have to get them out!"
Event manager Kezia Trask said the changing make-up of the events prompted them to extend the series entry pack to include children, families and students.
"It's great that everyone can do different distances," she said.
"The short courses are achievable for almost everyone - some are more challenging than others, and there is childcare available for children who don't want to run."
Trask offers some advice to newcomers to the series: "Come prepared with good shoes and a jacket - and a positive, adventurous attitude."
Forest trail
What: Blackmores Xterra Auckland Trail Run/Walk Series
When: Tomorrow
Where: Riverhead Forest, Auckland
For more information: http://www.trailrun.co.nz/aucklandseries/index.php