It's the first day of school and Joseph Barham's backpack is busting at the seams already.
Joseph weighs only 71 pounds, but his backpack is 22 pounds. On his walk to his second class he's so overloaded that he can't even stand up straight, and that is what has parents, teachers, and doctors concerned.
"We're really seeing an epidemic of back pain in children these days," Pediatric orthopedic surgeon Dr. Michael Vitale told The Early Show consumer correspondent Susan Koeppen.
Vitale says he sees kids every day who have pain because of overloaded book bags. The Consumer Product Safety Commission says that last year, nearly 4,000 kids went to the emergency room because of back pack injuries.
"Kids often have significant back pain that limits their activities, limits their ability to play sports and interact with peers, and it can't be a good thing to start having back pain at the age of 5 or 6," Vitale said.
Doctors say kids' backpacks shouldn't weigh more than 10 percent of their body weight, but many kids carry up to 50 percent of their weight in their bags.
"I could not carry some of the things that they are carrying," said Kathryn Glutz, principal of a New Jersey middle school.
Glutz's school has taken steps to lighten kids' loads. In a couple of classes, sixth graders get two sets of textbooks: one for school and one for home. Students are also taught how to be more organized.
But weight isn't the only problem. Dr. Vitale says how kids wear their bags can also cause strain.
When more than half the backpack is below the waist, Dr. Vitale said, it creates an unnatural force on the lower back. Additionally, when the backpack is around one shoulder, all that weight is really on a small set of muscles just on one side.
"This is really a set up for back pain," he said.
Dr. Vitale says the safest way to wear a backpack is up high and close to the body using both shoulder straps. It's good advice for kids like Joseph who needs all the support they can get on his daily hike to class.
Some tips to chose the right backpack for your child: