Pain in the back

A class project to weigh students’ backpacks held a massive surprise for Taylor Bartholomew: Her pack was 20 pounds.

The sixth-grader knew it was heavy: “I have my binder, plus an 800-page book, a 200-page book, my bike lock, house keys …”

But she didn’t know it weighed as much as an average car tire.

“The second I told my mom that my pack was 20 pounds, she told me to go and throw things away,” Taylor said.

While Taylor carried the heaviest load at Riverside Elementary School in Milwaukie, Ore., several students had packs of 15 pounds or more. One was in second grade.

When asked whether heavy packs ever hurt their backs or shoulders, most of the kids in both sixth-grade classes at Riverside raised their hands.

That’s no surprise to doctors who deal with kids’ muscles and bones. Medical studies have estimated that heavy backpacks are the main cause of children’s shoulder and back pain. A quarter of kids ages 11 to 14 said they’d had pain from heavy backpacks in the previous month, according to a British survey, with girls more likely to suffer strain than boys.

“We’re seeing a lot of kids that were having back pain,” said Dr. Henry Chambers, a pediatric orthopedic surgeon at Children’s Hospital and Health Center in San Diego. “It’s usually late elementary-school and middle-school kids that have this problem.”

That was certainly the case at Riverside, where the sixth-graders weighed every student’s pack. In the lower grades, most backpacks weighed just a pound or two. But starting in fourth grade, average weight rose notably, from 3.2 pounds to 4.3 pounds in fifth grade and 7.1 pounds in grade six. And the number of very heavy packs – 13, 15, 17, 20 pounds – also rose.

It’s important to note that the packs were weighed at the start of the school year. Many backpacks get heavier as the year goes on and old homework assignments, toys, food wrappers and other detritus accumulate. Chloe McCartney said her bag was so heavy by the end of fifth grade last spring that she had to drag it.

Backpacks should be lighter than 15 percent of a child’s weight, said Dr. Matthew Halsey, an orthopedic surgeon at Doernbecher Children’s Hospital in Portland, Ore. That means a 90-pound 12-year-old should have a backpack weighing less than 13.5 pounds. Sixth-grader Abagail Porter weighs 65 pounds, but her backpack weighed 15. That’s like a 200-pound man carrying a 45-pound pack, roughly equal to the training required of Army Rangers.

Pack weights rise as students get thicker textbooks and more assignments. But even students admit that homework is not the reason for the heaviest packs.

“A lot of us have a lot of junk in our backpacks – papers from forever ago, graded homework, toys,” sixth-grader Nick Goodwin said.

Other students chimed in with their contents: iPods, computer games, bottles of water, changes of clothes. Even lunchboxes and musical instrument cases get shoved into backpacks instead of being carried separately by their handles.

Weight is only half the problem. How kids carry the packs is another big source of trouble.

Chambers worked on a study in which doctors gave kids packs weighing from 10 percent to 30 percent of their body weight, then measured the pressure as the kids wore them on one or two shoulders, high on the back or slung low. They found that packs worn low, near the tailbone, or on just one shoulder were more likely to apply painfully high pressures.

“There’s so much pressure there’s no blood flow there, and eventually the nerves start hurting,” Chambers said. “It’s like when you sit down and your leg goes to sleep.”

Even when kids wore packs on both shoulders, the right shoulder felt much higher pressures, Chambers found. That’s probably from wearers’ postures, though the reasons are unclear.

To minimize pain, doctors say kids should get backpacks with thick, padded straps and wear them on both shoulders. The pack should be high on the back, not near the tailbone. And try to find a pack that buckles around the waist in front – and use that buckle.

Of course, rolling bags take almost all the weight off – if you can get kids to use them (and if the school allows them).

There is some good news: While many kids have some pain, it’s unlikely to cause lasting problems.

“There’s kind of an urban legend that wearing backpacks on one shoulder can cause scoliosis,” Halsey said. “That’s absolutely not true. Otherwise, scoliosis would be epidemic.”

Any pain is easily treated with ice packs, ibuprofen or acetaminophen (children should never take aspirin, which may cause a rare but deadly disease).

Chambers added one last obvious but important suggestion: “If it hurts when it comes off, you should reduce the weight.”