Backpacks damage kids' shoulders and backs

Kids today are carrying too much of a load on their backs and researchers say back pack weight should be reduced for comfort and safety.

The average backpack load of a typical U.S. teen in middle school is far too heavy and the researchers warn that excessive pressure on the shoulder from weighty backpacks may lead to shoulder pain, and low back pain.

The team from the University of California, San Diego School of Medicine say children are ending up in hospital emergency rooms each year due to injuries related to backpacks or book bags.

The Consumer Product Safety Commission estimates that number to be almost 7,500.

Brandon Macias, a principal investigator for the study, says that on the basis of their findings and recent unpublished data, they have four recommendations to make:

• backpacks should be positioned high on the back

• backpack straps should be over both shoulders

• weight in the backpacks should be minimized

• and backpacks should have wide straps.

Macias and his colleagues with help from ten 13-year-old students, five girls and five boys, looked at backpack weight and how it is distributed with regard to shoulder and back pain.

They then fitted each child's backpack with pressure sensors on the shoulder straps.

The children all wore standard identical backpacks first carrying 10 percent of their body weight, then 20 percent and finally 30 percent of their body weight.

The researchers saw an increase in pain levels in line with an increase in backpack weight.

Specifically, pressures exerted on the shoulder at backpack loads of 20 percent body weight were enough to reduce normal skin and muscle blood flow in that area.

Children usually carry backpack loads equal to 22 percent of their body weight.

Joint study leader Gita Murthy says this is not a new concern for parents but the data published is new and important.

Murthy says the more objective data that the public is given, the more educated they become, and the more inclined to change the way children carry backpacks.

The researchers hope that their findings will encourage backpack designers and engineers to build better backpacks with wider straps to help spread the load.

The study is published in the Archives of Pediatrics and Adolescent Medicine, December 2005.