When Homework Is a Pain in the Neck -- and Back

Dec. 6, 2005 — -- Schoolkids have always complained about having tons of homework. New research has now pinpointed how lugging around a heavy backpack is contributing to lower back and shoulder pain.

A study published Monday recommends four ways to reduce and redistribute the load children are carrying to avoid injuring young shoulders and backs.

Children generally carry about 22 percent of their body weight in backpacks -- for a teenager, that can amount to more than 30 pounds of books, food, calculators, iPods and other necessities of modern life.

When that amount of pressure is focused on one or two narrow shoulder straps, the weight can easily reduce blood flow to kids' skin and muscles.

"Even at 10 percent [of body weight], the pressures were still high, and that hasn't been quantified before," said Brandon Macias, lead author and researcher at the University of California, San Diego, Department of Orthopedic Surgery.

Shoulder the Burden and Tweak the Spine

Ten 13-year-old students -- five boys and five girls -- carried identical backpacks outfitted with pressure sensors on the shoulder straps. The pressures were measured when the packs were loaded with 10 percent of the students' body weight, then 20 percent, and finally 30 percent.

An unusual finding came to light -- even when both straps were used, pressure on the students' shoulders was uneven. "It seems like the right shoulder becomes loaded more," Macias said.

Uneven loading on shoulders over a period of years may alter the spine curvature and contribute to back pain, the researchers noted.

It's not just the amount of weight, but the way it's distributed that causes pain. The researchers concluded that, in addition to shoulder pain, an uneven backpack load can cause lower back pain.

The research team came up with the following recommendations based on its study. "The backpack should be positioned high on the back," said Macias, reducing the stress on the shoulders and back.

And backpack straps should be positioned over both shoulders, lowering the amount of weight carried by one shoulder. Wider straps also reduce the pressure on the shoulders.

And finally, "The weight in backpacks should be reduced," said Macias in a statement sure to cause rejoicing among overloaded students everywhere.