Bajin Milan, Kojić Milan, Romanov Romana, Ahmetović Zlatko
Faculty of Sport and Psychology, Educons University in Novi Sad, Novi Sad, Serbia.
Faculty of Sports and Physical Education, University of Belgrade, Belgrade, Serbia.
Front Pediatr. 2022 Nov 15;10:1045666. doi: 10.3389/fped.2022.1045666. eCollection 2022.
School bag (SB) load causes significant changes in the height and symmetry of the intervertebral discs at each level of the spine from T12-L1 to L5-S1. This study aims to determine the change in the size of the lumbar segment angle at a particularly critical point L3-L4 of the spine in relation to the load of the average weight of SB in healthy male children (students) at standing and after 2-minute gait.
47 boys, aged 12.2 ± 0.92 years, underwent photogrammetric measurements in the sagittal plane in statics and dynamics, walking on a laboratory treadmill. Measurements were repeated with the weight of SB with a constant load of 6,251 kg, which represents 13.78% of the average body weight of our sample. The lumbar angle (LA) connecting the point of the big toe, the lumbar point L3-L4 and the processus spinosus C7 was measured. In gait, LA was measured in the phases of the middle support and the initial contact of the heel.
T-test of paired samples was used to estimate the change in LA at standing from 4.953° and walking phases from 6.295° to 7.332° in relation to the unloaded state, and the value of the effect size (ES) indicates that the impact of SB load is significant.
Cumulatively, microtraumas caused by SB load significantly affect the increase in intervertebral pressure at the L3-L4 point, which is susceptible to degenerative processes and which can be the cause of lumbar syndrome (LS). Preventive measures are needed in order to lighten SB in this population and introduce up to 10% of students' body weight into the safe zone.
书包负重会使从胸12至腰1以及腰5至骶1的脊柱各节段椎间盘的高度和对称性发生显著变化。本研究旨在确定在健康男性儿童（学生）站立时以及两分钟步态后，脊柱特别关键的腰3至腰4节段角度大小相对于平均重量书包负重的变化情况。
47名年龄为12.2±0.92岁的男孩，在实验室跑步机上行走时，于静态和动态的矢状面进行摄影测量。在书包负重恒定为6.251千克（占我们样本平均体重的13.78%）的情况下重复测量。测量连接大脚趾点、腰3至腰4点和颈7棘突的腰椎角（LA）。在步态中，在中间支撑期和足跟初始接触期测量LA。
使用配对样本t检验来估计相对于无负重状态，站立时LA从4.953°变化，以及行走各阶段从6.295°至7.332°的变化情况，效应量（ES）值表明书包负重的影响显著。
累积起来，书包负重引起的微创伤会显著影响腰3至腰4点处椎间盘压力的增加，该部位易发生退变过程，可能是腰椎综合征（LS）的病因。需要采取预防措施来减轻该人群的书包重量，并将学生体重的10%纳入安全范围。
