WEDNESDAY, May 21, 2003 (HealthDayNews) -- While they may be crammed with everything but the kitchen sink, those heavy backpacks your children lug to school don't cause back pain.
That surprising finding comes from a new University of Michigan Health System study.
For years, experts have warned that children need to lighten their backpack loads, wear the packs on both shoulders to evenly distribute the load, and put down that burden whenever possible.
But a study by researcher Dr. Andrew Haig says those heavy backpacks don't actually inflict stress and strain on young backs. Haig is medical director of the university's Spine Program and an associate professor of physical medicine and rehabilitation and surgery at the the university's medical school.
"There is no good scientific evidence to support the claim that schoolbag load is a contributing factor to the development of low back pain in growing children," Haig says in a news release.
Instead, his study indicates a child's activity level and body weight may have more impact on whether they suffer back pain.
The study was presented May 21 at the World Congress of the International Society for Physical and Rehabilitation Medicine in Prague, Czech Republic.
For this study, students aged 7 to 15 were asked about their backpack use, back pain, activity levels and transportation to school. The children and their backpacks were weighed and the children's heights recorded. Those numbers were used to determine the backpack weight as a percentage of body weight.
Nearly all the students said they used a backpack every day. Third grade students carried an average of 5.7 percent of their body weight in their packs, while middle school students carried backpacks equal to 11.4 percent of their body weight.
Most children ignored warnings about putting both backpack straps over their shoulders and, instead, carried their packs over one shoulder.
More than a third of the children said they had at least one indicator of back pain. However, the study found those students didn't carry heavier backpacks than children with no indicators of back pain.
The study also found there was no relationship between back pain and whether students wore their backpacks on one or both shoulders.
Middle school children were more likely than younger children (45 percent versus 15 percent) to report back pain. That could be the result of the children's declining activity levels and physical condition.
"The students' body mass index, an indicator of obesity, increased from the third graders to middle schoolers, so the middle schoolers were more fat. Also, the percent of students who walked or biked to school dropped dramatically in the older kids, so they're much less active. At the same time, they reported watching much more TV and spending more time playing video games," Haig says in the news release.
"Frankly, I think that might be more of a factor in back pain than the backpacks," he says.
He says exercise squeezes and stretches spinal discs, which act as shock absorbers for the back. This exercise-generated motion pumps in nutrients and oxygen, which help keep the discs healthy. Without that movement, spinal discs may lack nutrition and that may lead to back pain.
More information
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