The growing popularity of trampoline parks has doctors worried, with a bounce in the numbers of kids ending up in hospital across the Tasman after mistimed falls.
About three new trampoline centres open in Australia every month. Many of them include not just ordinary tramps, but also foam pits to land in, walls to jump onto and tramps on angles for doing tricks on.
According to a new study published in journal Injury Prevention, 40 kids showed up to Sydney Children's Hospital's trauma centre in just six months after being hurt at a trampoline park. The average age was 10, and the youngest just a year old.
Most of them failed to land properly, with 20 percent of injuries being caused by a "double-bounce" - when two people are bouncing together, and the energy from the larger is transferred to the smaller, causing them to bounce a lot higher and perhaps in a different direction to what they were expecting.
One of these double-bounces saw two kids collide, and require medical treatment.
Five of the kids were trying to do somersaults or flips. Six hurt themselves on the protective padding around the edges of the trampoline. Five of the 40 required surgery.
Trampoline parks are seen by many parents as a safer option than using a trampoline at home, but the research - though focused on a small geographical area in Sydney - suggests they have a similar hospital admission rate.
The researchers say it's likely because double-bouncing appears more common at trampoline parks, despite many banning the sharing of trampolines. They also suggest the large numbers of children at trampoline parks, when compared to back yards, could encourage risky behaviour.
"Other issues that warrant further investigation are the risk-taking and behavioural differences of children in large groups, who may visit trampoline parks without direct parental supervision, compared with domestic trampolines."
A recent New Zealand study found trampoline injuries leap in summer, particularly when daylight saving kicks in - giving kids an extra hour of bouncing.
And last year, Australian researchers found the introduction of safety nets did nothing to stop kids hurting themselves - the blame placed on decreased parental supervision.