MINNEAPOLIS (WCCO) – A study in the journal Pediatrics found that the rate of inflatable bounce house injuries has skyrocketed from 5,300 emergency room visits in 2008 to more than 11,000 visits in 2010.

More than a third of the children involved in the injuries were under the age of six, the study found. The most common injuries were fractures and sprains.

Bounce houses (or moonwalks) are inflatable structures in which children can jump around, in a way similar to a trampoline. They’ve become popular in recent years as companies rent them for birthday parties and the like.

Randall Pinkston has more on how to help keep kids safe while bouncing in the video above.