Parents like you are increasingly expressing their concerns to teachers, principals, and school board members about the dangers of children wearing heavy backpacks. But before making a case for change in school policies around the use and wearing of heavy packs, some research would be helpful.
Several different studies have been done looking at various aspects of backpack usage in school-aged children. Most recently, 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 was 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.
Whether or not there is a direct link between backpack use and the development of scoliosis (curvature of the spine) has not been proven. But studies like this one offer some evidence that there is a direct effect of wearing a backpack with heavy loads on spinal alignment. No doubt more studies will be carried out and published in the near future as this topic is of major concern to physicians, parents, and school officials.