As school starts, we ask: Is your child's backpack too heavy?

Many Eastern Iowa kids are loading up their backpacks and heading back to school. But do you know how heavy those book bags really are?

Health officials warn if parents and students are not careful, heavy backpacks could cause serious health problems.

"Pencils, erasers, math book,” said Cameron Kelso, who says he has everything he needs for his first day of third grade at Wright Elementary School in Cedar Rapids.

But even with all the excitement about school supplies, Chiropractor Colette Murphy said parents need to keep an eye on kids to keep them out of her office.

"Every year, a couple months into the school year, children come in with back pains,” Murphy said.

It comes from carrying too much in their book bags.

Murphy says the rule of thumb is that students shouldn't haul more than 10 to 15 percent of their total body weight.

"You create an imbalance or a weakness that will go with them for the rest of their lives," Murphy said.

Wright Elementary third grade teacher Sarah Evan-Schwartz sees it all first hand.

"You can actually walk in the hall and see kids dragging their bags because they're so heavy,” Evan-Schwartz said.

Cameron didn't know how much his backpack was weighing him down. "I've never done a school book weigh-in,” Kelso said.

So we put his soon-to-be book load to the test.

In the end, if a third grade Wright Elementary student carries every book, it would weigh about seven pounds without a book bag.

That's almost ten percent of the average third grade child's weight.

Teachers said, however, it is very rare for Wright Elementary students to carry around all of their books.

Still, chiropractors said it's something for parents to look out for.