ACC says too much sport may be just as harmful for children as not getting enough exercise.
It's released alarming figures showing a huge spike in sports injuries in the past decade, especially in young people.
Under-10s have seen the biggest spike: from 2008 to 2017, they went up 63 percent - a jump from 4500 injuries to 7350 injuries.
Sports injuries to kids aged 10 to 14 have gone up 60 percent, and the numbers are even more startling - from 25,300 to 40,600.
Kenzee Boucher is in Year 11 and the basketball court is her happy place - although judging by her injury count, it's also been the source of a few tears.
"Last year I injured my ankle three times, I was in a moonboot twice," she told Newshub.
"I had severed something in my neck from basketball, cracked my ribs, heaps of finger injuries, dislocated my elbow...oh and I possibly dislocated my knee as well, but it went right back in."
She's made at least 15 ACC claims, but even her mum Nikki Boucher has lost count.
"I think they're sick of seeing her name come through."
Kenzee plays for at least 10 different teams across five sports, has at least two trainings every day and three games a week.
"I enjoy it, I do, but sometimes I just want to sleep," she said. "But it's nice coming to training and seeing all your friends and having fun with them as well."
"With her we can tell when she's doing too much," Boucher said. "She gets really tired, moody, grumpy. So we monitor her to make sure she isn't burning herself out."
She's one of close to 50,000 young people sidelined by injury every year.
Dr Dan Exeter from Athletics New Zealand is one of the country's top sports doctors, and said a diversity of sports for kids is key.
"It's the difference between limiting organised sport but not at all trying to limit the creative free play that we think is important for a lot of different reasons," he said.
"There's a perception that in order to be a successful sports person you've got to start early, but actually the evidence is to the contrary. If you want to be good at any one sport you should sample a whole range of sports early."
So the 10,000 hour concept, where hitting a golf ball for 10,000 hours will turn you into Tiger Woods, holds no weight.
In fact, parents wanting to limit children's injuries should use the one hour for every year rule. So a 10-year-old should do no more than 10 hours of organised sport per week.
"There's a lot of emphasis that goes into the outcome and winning, rather than the development process," Alex Chiet from Sport New Zealand said.
"What's important in young development years is kids enjoy themselves. They learn from mistakes and have fun with their friends."
Kenzee's had a number of friends drop out because they were simply pushed too hard. But her coach and father, who just happens to be Tall Black great Dillon Boucher, isn't like that.
"I do it for my own enjoyment, not for anyone else's," she said.
Experts agree that's the right approach.