Effect of backpack load placement on posture and spinal curvature in prepubescent children

Parents, educators and researchers have expressed concern about the long term impacts of children carrying excessive loads in their backpacks on a daily basis. Although many researchers have investigated appropriate weight limits for children's packs, little research has been conducted on the design of children's backpacks. The purpose of this study was to evaluate the changes in children's trunk forward lean (TFL), cranio-vertebral angle (CVA) and spinal lordosis angle (LA) that occurred with high, medium and low load locations during standing and walking. Ten-year-old children (n = 15) completed a repeated measures designed study while carrying 15% of each child's body weight in a typical backpack with only shoulder straps. A special instrumented backpack (IBP) was designed that allowed the weight to be placed in the proper location and continuously measure changes in spinal curvature. TFL and CVA postures were captured on digital video at five intervals including: standing without a backpack prior to a 1000 m walk; standing with a backpack at the beginning and end of a 1000 m walk; and walking with a backpack at the beginning and end of a 1000 m walk. Results indicated that significant changes occurred in TFL and CVA when the backpack was loaded to 15% body weight. The low load placement in the backpack produced fewer changes in CVA from the initial standing baseline measure than the high and mid placements. When all measures were assessed collectively, there were fewer changes in LA in the low load placement. These findings indicate that future backpack designs should place loads lower on the spine in order to minimize children's postural adaptations.