Any kind of exercise is allowed, not just running or walking, Unsworth said.
"It's not just between schools either, there are internal battles going on between houses as well.
"As long as they're uploading proof of their activity, whether it be a screenshot of their Strava or a video of them walking the bridges or something, then it'll be logged."
As of Thursday morning, there was a close battle between Whanganui Girls' College and Whanganui City College for the top spot.
City College was sitting at 1893km, with Girls' College just behind on 1588km.
At the other end of the scale, Ruapehu College had logged just 12km.
City College's Alexander was out in front for the house challenge, with 704km.
It's not just students who can get involved.
"There are over 1000 entries now, and 52 per cent of them have come from teachers and support staff," Unsworth said.
"It's great to see them getting in behind it. It's all about setting examples."
There was still a long way to go, but the possibility of challenge "hacks" could result in a winner sooner rather than later, Unsworth said.
"Some of them have caught on that if you get a sports team to do it, that's an hour and a half of training times 15 people.
That led to some pretty quick point gains, Unsworth said.
"There have been PE classes uploading for 30 students at 60 minutes apiece as well.
"It's cheeky, but as long as they're moving it's fine. Every school is welcome to do it."
Unsworth said this year's lockdown had caused the cancellation of Whanganui's winter tournament week for the second year in a row.
"A lot of kids are missing out on certain things, but the challenge will at least let them compete locally with one another.
"It gets them moving too, of course."
For more information on this year's Aotearoa Activity Challenge, go to www.sportwhanganui.co.nz/secondary-school/