It's the latest craze sweeping the nation: trampoline parks. They look like trampolines on steroids!
But, are these facilities safe? Or, are they just a recipe for disaster?
Brett Kromeich was having a great time at a trampoline park in Chicago, until he snapped his leg in two places.
One of Kromeich's friends caught the accident on camera, and you can actually hear the sound of Brett's bone breaking on the video.
"It just completely snapped my leg in half," said Kromeich.
He had to have emergency surgery just to save his leg.
The accident took place at Xtreme Trampolines near Chicago.
Trampoline park centers have been popping up all over the country. It looks like fun, but experts say many trampoline centers aren't doing enough to make them safe.
Veteran gymnastics coach Don McPherson said trampoline parks violate a cardinal rule of trampoline safety.
"No more than one person on the trampoline—ever," McPherson said.
Unlike in gymnastics, he said there are no state or government safety regulations for jump centers.
He showed us what can happen when two people bounce on a trampoline at the same time.
"It makes one person jump really high and out of control," he said.
He says jumpers run the risk of crashing into each other.
McPherson said an inexperienced jumper catapulting head first into the foam pit is potentially lethal.
"They can break their necks, their back and their collar bones, or all three at once - in a fowl swoop," said McPherson.
INSIDE EDITION found top athletes have faced serious trampoline park injuries.
Last month, New York Yankee's star relief pitcher Joba Chamberlain suffered a potentially career-ending ankle injury while jumping at a Florida trampoline park.
In February, at a Phoenix trampoline park, 30-year-old Ty Thomasson lost his life after he broke his neck jumping head first into the foam pit.
"The only way to enter a foam pit from a trampoline is feet first," McPherson told INSIDE EDITION.
But, that's not what our hidden cameras found at trampoline parks across the USA.
At a jump center in Scottsdale, Arizona, we saw children flipping into foam pits. We even saw smaller kids, buried in foam struggling to climb out.
There was zero supervision at other trampoline parks INSIDE EDITION's Lisa Guerrero and the I-Squad checked out.
We saw a young boy jumping on a trampoline with no employees monitoring the area.
Back at Xtreme Trampolines in Chicago, where Brett Kromeich broke his leg in half, the I-Squad found a two-and-a half year old boy jumping in a section designated for ages 14 and up.
He was also playing dodge ball with grown men. Our hidden cameras caught one guy almost stepping on him by accident.
Everything was apparently ignored by the people in charge of supervising the trampoline park, the safety monitors.
They seemed to be too busy tossing a ball, dancing, even chatting it up with other patrons.
Xtreme Trampolines Owner Eric Beck acknowledged to INSIDE EDITION that at least 25 emergency calls have been made since 2011 at the two trampoline park locations that he owns.
INSIDE EDITION's Guerrero showed Beck the undercover video.
"Where are your employees?" Guerrero asked Beck. "Why aren't they saying, 'Sir you have to get the child off the trampoline?' "
"They should be. They should be." Beck responded. "I see some things in there that they absolutely should be doing. If they miss something, it's going to be on their shoulders."