In the late 1980s, a New Zealand engineer named Keith Alexander wanted to buy a trampoline for his kids. After his wife said they were too dangerous, Keith set out to design his own — a safer ...

Rachel Brashier brings her 3-year old son to the park to play to get exercise, because she thinks it's safer than a backyard trampoline. "I've heard, like, broken arms, situations like that, you know, ...