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The popularity of trampoline parks is growing by leaps and bounds — along with injuries among their visitors, particularly young children.
Less than a decade ago, there were only three trampoline parks in the nation. Now there are roughly 800. While thousands of customers walk away from their visits unharmed, warnings about the largely unregulated industry are mounting.
Chelsea Zeolla, 12, was bouncing and doing flips at Flight Trampoline Park in Connecticut when she landed on her arm and broke it. She now bears a scar where doctors inserted a pin to help set her arm.
The facility’s owner, Ralph Park, admits that the centers can be dangerous.
“You can break a bone. You can have a compound fracture,” he said.
Park owns 11 trampoline parks. Visitors at each one are required to watch a safety video and sign a waiver before they take their first leap.
"Of course, we don't want to see any injury,” he said. “We want to find out why that injury happened and again, we want to try to prevent injuries from happening."
Only nine states have regulations dealing with trampoline parks. Kids aren’t the only ones getting hurt at the facilities.
In 2012, former Yankee pitcher Joba Chamberlain visited a trampoline center with his son – and ended up breaking his ankle so severely that he suffered severe from extreme blood loss.
According to the American Academy of Pediatrics, the number of emergency room visits from trampoline park incidents have soared, from 581 in 2010, to 6,932 just four years later.
Attorney David Chazen represents six clients who he says were injured at a Sky Zone Trampoline Park. The youngest is 4-year-old Jeremiah Lang, who broke his leg when an older child bounced on top of him.
"Sky Zone has a policy that anybody who can walk can go on their trampolines," he said.
In a statement to NBC News, Sky Zone asserted that “the safety of our guests is our top priority.”
“As with any physical activity or sport, there are inherent risks. We take several measures to reduce these risks and educate our guests about safety in our parks,” the company said in its statement.
Chazen said injuries at trampoline parks can be devastating to children, and their parents.
"The parents feel tremendous guilt, because when they look at this in hindsight and they regret having allowed their children to go to Sky Zone,” he said.
The American Academy of Orthopedic Surgeons recommends that trampolines not be used by children under six. The American Academy of Pediatrics, however, advises against trampolines for all children.