The number of children hurt while using inflatable bouncers, such as bouncy castles, is 15 times higher than in 1995, according to a new study.
US researchers, who published their findings in the journal Pediatrics, said there are about five bounce house-related injuries per 100,000 US children every year.
That's far less than the estimated 31 trampoline-related injuries per 100,000 US children reported in 2009, but the study's lead author says the new findings should make people take notice.
"Groups should take a look at these data, help us get the word out and make sure parents are making informed decisions," said Dr Gary Smith, director of the Center for Injury Research and Policy at Nationwide Children's Hospital in Columbus, Ohio.
The number of kids being brought into emergency rooms (ERs) for the injuries increased from 702 in 1995 to 11,311 children in 2010.
Broken bones and sprains were the most common types of injuries with each accounting for about a quarter of the ER visits. Cuts, concussions and bruises made up the rest.
Smith suggested that parents limit the use of bouncy castles to children about 6 years old and older, limit the number of children using them at one time, and always have a parent present.
Until now, according to the researchers, there had only been one other study looking at bouncer-related injuries, and that only looked at broken bones in a small number of patients at one hospital.
For their new study, the researchers used information from a database of injuries related to consumer products that were treated at about 100 US ERs between 1990 and 2010.
From that database, Smith and his colleagues were able to estimate that about 65,000 children and teens were treated for bouncer-related injuries during that time.
About a third were under five years old, half were between six and 12 years old, and the rest were between 13 and 17 years old.
They found that the rate grew toward the end of the study with the annual number of injured children more than doubling from 2008 to 2010.
The most likely explanation for the increase is more children using inflatable bouncers.
"We tried really hard to get those numbers," said Smith. "We generally got the feedback that the usage was going up but we couldn't get any firm numbers."
Dr Tigran Avoian, the author of the previous study on bouncer-related broken bones, said it could also be attributed to other factors, such as better reporting by hospitals.
"I don't think it's related to an epidemic," said Avoian of the Los Angeles Orthopaedic Hospital, who was not involved in the new study.
In an email to Reuters Health, John Carr, of the American Inflatable Alliance, warns that the new study does not say how many children who use inflatable bouncers got injured.
He added that - by his calculations - children may use bouncers as many as 643 million times per year.
"When utilisation is factored in, injury rates are actually quite small," he writes.
SIMILAR TO TRAMPOLINES
The researchers point out that - aside from the frequency - inflatable bouncer-related injuries were similar to previous findings on trampoline injuries.
Specifically, arm injuries decreased, while leg injuries increased, as children got older.
Also, the number of children needing to be hospitalised - about 3 per cent - in the new study was about the same as for trampoline-related injuries.
Earlier this year, the American Academy of Pediatrics advised against the use of trampolines at homes and playgrounds. But Smith told Reuters Health that a similar recommendation for bouncers is probably not wise.
"My personal philosophy is that we need to try to get children off the couch so that they are physically active and develop a healthy and active lifestyle, but understand any activity comes with risks... So the purpose was not to be an alarmist, but to make sure parents understand the risks," he said.
In his previous study, Avoian and his colleagues suggested that children playing in bouncy toys be supervised and broken into groups by size.
"They should know kids can get serious injuries, but it could be prevented," said Avoian.