Effects of carrying a backpack in an asymmetrical manner on the asymmetries of the trunk and parameters defining lateral flexion of the spine.

Objective: The aim of this study was to examine changes in the body posture parameters defining asymmetry of the trunk and lateral flexion of the spine in children while carrying a backpack weighing 10% of a child's weight.
Background: Carrying a backpack may negatively affect the posture of schoolchildren and contribute to spinal pain.
Method: The study involved 162 primary school students ages 11 to 13 years. The parameters describing body posture were assessed with a backpack carried on the right or left shoulder as well as without a load. To assess the predefined parameters, we used the CQ Elektronik System, employing the photogrammetric method.
Results: Trunk inclination shifted significantly in the opposite direction to the shoulder the backpack was carried on, and an increase in shoulder asymmetry was also found. We also observed a more pronounced right-side lateral flexion of the spine when the backpack was carried on the right shoulder and an analogous relationship for the left side.
Conclusion: The results of this study show that carrying a backpack in an asymmetrical manner negatively affects spine, even if the backpack weight constitutes 10% of the child's weight, which has been previously recommended as a safe load for a child's shoulders.
Application: We suggest that the issue of safe backpack weight be reassessed and that students be taught basic ergonomic principles on how to carry loads. Changes to the management pattern of carrying textbooks to and from school also should be considered.
(© 2014, Human Factors and Ergonomics Society.)