"Take a load off" is good advice when it comes to backpacks, particularly for children. Toting too much weight can wreck their posture and strain their still-developing frames.
It's not so much the risk of immediate back problems – a 2003 study published in Pediatrics, the official journal of the American Academy of Pediatrics found that most backpack-related injuries that required medical treatment were due to tripping over a backpack, improperly wearing a backpack or being hit with one worn by a careless classmate. More of those injuries involved the head, hand, wrist or shoulder than they did the back.
Still, orthopedists caution that improperly used backpacks can contribute to muscle and joint strain, as well severe back, neck, and shoulder pain as well as posture problems.
The problem usually starts with the weight of the pack. The American Academy of Orthopaedic Surgeons recommends that it be no more than 15 to 20 percent of the child's weight. If you have a smallish kindergartner, that's only six to eight pounds for a 40-pound kid.
You can help your children downsize by making sure they pare the pack to the essentials every night, helping them remove anything that isn't necessary for the next day.
Also fit the backpack to your child, rechecking periodically during the year if your child has a growth spurt. The backpack should be rest on the center of child's back and fall no lower than his lower back. The straps should be adjusted until they're loose enough that the child easily can put on and take off the backpack and not so tight that they're cutting into the shoulders.
It's never too soon to start teaching proper ergonomics, either. Remind your child to "lift with your legs" with bended knees rather than reaching straight down to pick up a heavy load.
For more information:
Tell-tale signs it's too much
Here are some ways to tell if your child's carrying too much weight:
Source: National Safety Council
Tips for choosing the right backpack
Source: American Academy of Orthopaedic Surgeons