There's a new warning about backyard trampolines. The American Academy of Pediatrics is recommending against recreational trampoline use. --A new study reveals that in 2009, there were an estimated 98,000 trampoline-related injuries in the U.S., resulting in 3,100 hospital visits. The study finds that safety measures haven't changed injury rates and kids under the age of 5 are at greater risk. They also found that safety netting and padding did not change the amount of injuries.