If you are a parent of a school age child, you’ve probably wondered if carrying those heavy backpacks is really such a good idea. But when you suggested trying a rolling backpack, all you got was an eye roll and the message that those just aren’t cool. So your son or daughter continues to struggle under the weight of a backpack that can sometimes equal one-fourth of their body weight.
But what can you do? The results of this study might give you the ammunition you need to make some changes. Parents are increasingly expressing their concerns to teachers, principals, and school board members. These individuals and groups can set school policies to limit size, weight, and usage of backpacks. Children can be given time in the school day to complete assignments and studies that would otherwise require carrying multiple heavy books home.
So, just how dangerous is it to wear these backpacks? Researchers from the University of California (San Diego) teamed up with doctors from Rady Children’s Hospital (also in San Diego) to conduct an experiment. They used standing magnetic resonance imaging (MRIs) to measure the physical effects on children’s spines from wearing backpacks of differing weights. Boys and girls between the ages of nine and 14 were loaded down with 12, 22, and 32 pound backpack loads. That’s about 10, 20, and 30 per cent of their body weight. MRIs were taken with each of these weights.
Two MRI measurements were made: disc height and spine curvature. The researchers were expecting to see narrowing of the lumbar discs as a sign that the vertebral bodies were compressed under increasing loads. And that’s exactly what they saw. They also saw lumbar asymmetry (curvature of the spine in the low back region). And when they had the children report and rate their level of back pain, there was a significant increase in low back pain linked with wearing these heavy loads.
This is the first study using radiographic imaging to provide solid evidence that high contact pressures from heavy backpacks leads to back pain and abnormal compressive forces on the spine. Measurements taken showed that there was increased load throughout the lumbar spine (from T12-L1 all the way down to L5-S1). The greatest load was recorded at the L5-S1 segment. And as the children adjusted their posture to higher loads, the spine started to curve to one side or the other. The children shifted the load to the right shoulder most often in an attempt to balance their center of gravity with the heavier loads.
The results of this study highlight the effects of heavy backpack loads on the lumbar spine. And that was with wearing the pack on both shoulders at the same time. Other studies have used the same two-strap pack configuration but looked at pelvic position. The pelvis also shifts to accommodate loads causing asymmetry (unevenness) and rotation of the pelvis below the lumbar spine. It is assumed that these responses to backpack load would change even more dramatically when the backpack is worn on just one shoulder. That’s the way many children wear their backpacks most often.
The authors point out that in this study, the children wore the backpacks for a total of 30 minutes (about 10 minutes with each load). That’s not an accurate reflection of how it is at school where they are more likely to wear their packs for 30 to 60 minutes every day. They do tend to take the pack off and on during that time, which might help off load the spine with each episode of wear.
More studies are needed to help show the long-term effects of wearing a backpack. Considering that children are in school 10 or more years, the use and effects of backpacks over at least that time period need to be investigated. Comparing children at different ages and body weights who wear backpacks to those who don’t wear them would also provide additional information. With this type of data, school officials and parents would be better equipped to make and enforce policies to protect children.