In Brief:
This cross-sectional study investigated the influence of backpack carrying on the sagittal spinal curves, shoulder level shift, coronal sagittal upper trunk shift, back pain in school adolescents with the use of logistic multinomial logistic analysis. Backpack carrying resulted in forward lean of the upper trunk decrease of cervical lordosis. Asymmetrically backpack carrying forced adolescents to raise the backpack bearing shoulder simultaneously to move the upper trunk contralaterally. These changes increased the incidence of back pain in the school period during the holidays, particularly in girls. Carrying of backpacks symmetrically with two straps is recommended.