The effects of different backpacks weights on postural alignment of children of school age

Abstract

The aim of this study was to analyze the acute effect of different weights of backpack on body posture and assess the reliability of these measures. Were evaluated 50 students aged between eight and 14 years old. The students were photographed in the coronal and sagittal planes with different backpack loads: no backpack, the weight commonly used, with 10%, 15% and 20% of body weight. To compare the angles of asymmetry of the head, shoulders, pelvis, trochanter, knee, malleolus, body, sagittal head, shoulder sagittal and sagittal body was used ANOVA for repeated measures and the Friedman test. Reliability was analyzed using the intraclass correlation coefficient (ICC). Statistically significant difference were observed in the sagittal angle of the head (p < .00), in the sagittal body angle (p < .00) and the sagittal angle of the shoulders (p < .01) with increasing load. The data shows high inter-rater reliability (ICC > .83) for all angles measured in different postures (p < .05). This study does not support the recommendation that the weight of the backpack should not exceed 10% of body weight since smaller loads also caused anterior displacement of the head and body.