Backyard trampolines can be sources of endless amusement, popularity boosters among neighborhood kids ... and the basis of some really gross fail stories. Case-in-point: A 12-year-old British boy is lucky to be alive after a trampoline spring broke free, sailed through the air and lodged itself in his back. The incident happened over the weekend when Jamie Quinlan was jumping on a friend's trampoline, Jamie's dad Ian says."The spring had come off the trampoline like a bullet," he says. "If it had hit elsewhere on Jamie’s body, in his head or throat, we could have lost him." That's not to say Jamie made it out unscathed. Doctors say the spring was embedded two inches deep in his back. The U.S. Consumer Product Safety Commission says there are roughly 94,000 emergency room-treated trampoline injuries every year.