You might think your kids are safest playing in your own backyard. After all, they know it well, and you’ve taken great care to make it kid-friendly. Plus, you don’t have to worry about shielding them from that aggressive little guy at the neighborhood park … you know, the biter.

Well, your instincts on this one are partly right. A study of 40,000 kids treated in Canadian hospital emergency rooms for playground falls shows that most of the injuries were sustained at public playgrounds. And public playground falls were more likely to result in head or neck injuries.

But kids who got hurt on play sets in their own backyards and sought E-R care had greater chances of suffering broken bones, or sustaining injuries that required medical follow-up or admission to the hospital. Home slides were a big source of trouble for preschool-age kids: falls there were 72 percent more likely to result in severe injuries than falls from public slides.

If these statistics surprise you, ask yourself one question: what’s underneath your child’s play set at home? In 91 percent of cases, the answer is nothing, according to the Consumer Product Safety Commission. But 80 percent of public playgrounds have some sort of material to cushion junior’s falls.

Wondering what you should put under the kiddo’s play set? The commission says a thick layer of mulch, engineered wood fiber or shredded rubber should do the trick. If you don’t want pesky scraps of wood or rubber strewn about the yard or clogging up your lawnmower, consider more solid options. Experts say rubber tiles are designed for this purpose. Professionally poured rubber surfaces work, too.

If these materials prevent a few E-R trips, they’ll pay for themselves. Besides, we know you can’t put a price on the value of keeping your little ones safe and healthy.