The effects of backpack loads and placements on postural deviation in healthy Malaysian school children

Abstract

Background: Studies on the effects of children's backpacks continue to receive attention from researchers despite it being extensively discussed over the past decade. This concern has a strong basis because scientific literature has revealed significant associations between carrying heavy backpacks and the immediate or future health effects on children, including musculoskeletal pain as well as physiological, biomechanical and psychosocial effects. The purpose of this study was to investigate the effects of backpack load and placement on postural deviation in healthy Malaysian school children. Methods: A randomized control experimental study was conducted on 136 healthy school children in Malaysia using systematic random sampling. Inclusion criteria were school children aged between 6 and 12 years old, free from any musculoskeletal diseases or disorders, able to stand upright and happy to wear biking shorts and tight t-shirts. Nine postural angles were measured during interventions namely the trunk, neck, gaze, head on neck, lower limb, tragus, acromion and pelvic. An intervention condition comprises the combinations of three backpack loads (5%, 10% or 15% BW) and three placements on the back (T7, T12 or L3). Photographs of the sagittal and frontal plane were taken during unloaded (baseline) and interventions. Postural angles were measured using the UTHSCSA Image Tool software. Changes in postural angles were assessed using the repeated measures ANOVA. The Pearson’s correlation test was performed to determine the relationship between postural angles with the participants’ characteristics (age, gender and BMI) while the Chi-square test was performed to identify the association between participants’ physical characteristics and perception of discomforts. Results: The angle of the trunk, neck, gaze, head on neck, lower limb changes significantly when carrying the backpack load of 10% BW placed at T7 and T12. All postural angles (the trunk, neck, gaze, head on neck, lower limb, tragus, acromion and pelvic, tragus, acromion and pelvic) changed significantly when carrying a backpack load of 15% BW regardless of placement (T7, T12, L3); p < 0.01. A significant association was also found between age and the angle of trunk and neck as well as BMI and the angle of the neck and lower limb; p < 0.05. However, no significant association was found between participants’ physical characteristic and perceptions of discomfort. Conclusions: School children should not carry backpack loads exceeding 15% BW and the backpack should be placed at a lower location on the back (L3) to reduce postural deviations.