Miss Gregory said they had all been "really excited" and it had probably been one of the most hectic starts in terms of everyone being pumped and excited.
"I think it's great for kids to be able to push themselves out of their comfort zone."
She said it was probably an environment not a lot of them had been in, and was something a little different.
"I think it's great to see them getting out there and having fun, and the smiles on their faces when they cross the finish line is what it's all about."
Event promotions general manager Murray Fleming said Cure Kids was the principal charity of the event, including the adult challenges which take place today and next Saturday at the same venue.
He said so far around the country the Tough Guy and Gal Challenges had raised just under $50,000 and they were hoping to top that figure by the end of the series.
Jimmy Jack Tapsell, 9, said it was "dirty and fun, and there was big puddles you fell over in".
He said there were obstacles to jump over, and his favourite part was running through the mud.
It was Jimmy Jack's first time doing the challenge and he would definitely do it again, he said.
Katie Tapsell, 11, said this was her second time doing the event and she was there with her school Mokoia Intermediate.
"I thought it was very gruelling running up those big hills, but a really great experience."
Maddox Smythe, 11, from Cambridge East School, said it was "way better than cross country".
Maddox said the hardest parts were going up a hill using rope and going underneath barbed wire.
"The best part was probably the end with all the mud."