The effect of backpack load on motion coordination of schoolchildren

The aim of this study was to explore the influence of the load of a backpack on the coordination of motion of healthy children aged 7 to 12. 100 healthy schoolchildren were recruited and they were quantified with the normal BMI, no foot deformities or injuries, no abnormal gait patterns. Coda Motion System was used to record the angle of walking with backpack loads of 0%, 5%, 10%, 15%, 20% and 25% of their body weight (BW) randomly. Vector angles between angle of head, body, knee and ankle were first calculated and then the phase angle (PA) and continuous relative phase (CRP) including their standard deviations (SD) were figured out. Distinctions within six load condition were evaluated by covariance univariance with significance level of 0.05 and a confidence interval of 95%. Our results show that significant effect loading on the CRP of head and body was found (p=0.005<0.01), where 0%BW (p=0.002<0.05), 5%BW (p=0.001<0.05) and 10%BW (p=0.008<0.05) were recorded with smaller CRP values than those of 20%BW. However, no significant distinctions were found between 20%BW and 25%BW. Although significant differences were not found for all PA variables, their decreased simultaneously with the weight of backpack increasing, particularly in the body and ankle. Overall, coordination in motion of schoolchildren was partially influenced by an increasing load of the backpack, as significant body tilt was performed by the children to overcome the backwards drag, while other body parts were not affected.