背包重量与背包方式对儿童身体姿势的影响

Effects of Schoolbag Weight and Backing Mode on Children’s Body Posture

目的:探讨不同背包重量和背包方式对儿童背包时身体姿势的影响。方法:选取杭州市某小学36名7~12周岁的儿童为实验对象,分别采用无背包、不同背包重量(10%体重、15%体重)、不同背包方式[背包方式Ⅰ:高背包中心(简称高背)和低背包中心(简称低背)2种;背包方式Ⅱ:有、无固定带]等实验设计自然行走。运用2台SONY DCRHC52E摄像机记录实验过程,采用SIMI Motion 7.5运动解析系统对相关身体姿势角度进行解析。通过SPSS 20.0软件,采用单因素方差分析和重复测量方差分析,对背包与无背包状态下儿童身体姿势的变化及年龄、性别、书包重量、不同背包方式对身体姿势角度的影响进行研究。结果:(1)所有背包负重状态下颈曲角(vranio-vertebral angle,CVA)、躯干角(truck angle,TA)及矢状肩姿势角(sagittal shoulder posture angle,SSP)(除10%体重背包重量、低背)与无背包相比,差异具有统计学意义(P<0.05);(2)年龄、背包重量、背包方式Ⅰ、背包方式Ⅱ对CVA、TA、冠状肩姿势角(coronal shoulder posture angle,CSP)角度的主效应显著(P<0.01);性别、背包重量、背包方式Ⅰ、背包方式Ⅱ对SSP角度的主效应显著(P<0.05)。年龄与背包重量、背包方式Ⅰ、背包方式Ⅱ等的交互效应对CVA角度的影响具有统计学意义(P?0.05);年龄、背包重量与背包方式Ⅰ等的交互效应对TA角度的影响具有统计学意义(P?0.05);性别与背包方式Ⅰ,背包重量与背包方式Ⅰ、背包方式Ⅱ等的交互效应对SSP角度的影响具有统计学意义(P?0.05)。低重量、低背、有固定带状态对儿童身体姿势影响较小,且相同负重下低年龄段儿童的身体姿势变化较小。结论:(1)与无背包状态相比,当背包重量达到体重10%时,大部分身体姿势角度会受到重量的影响而发生改变,高年龄段儿童(10~12周岁)受到背包的影响更大。(2)将背包中心高度控制在较低位置(腰部)、背包加装腰带和胸带能够有效缓解背包重量带来的身体姿势变化。

Objective To explore the effect of different bearing weights and carrying modes of schoolbags on children’s body posture.Methods Thirty-six kids aged from 7 to 12 from a primary school in Hangzhou were instructed to walk in a natural way without or with bearing schoolbags of different weights[10%body weight(BW)or 15%BW)],in backing modeⅠ(high or low load placements)and backing modeⅡ(fixing belts on or off).The whole experiment process was recorded using 2 SONY DCRHC52 E cameras and the data collected from various angles were analyzed using SIMI Motion 7.5 Sport Analyzing System.With the help of software SPSS20.0,One-way ANOVA and repeated measures ANOVA were used to examine the effects on children’s body posture.Results Significant differences were observed in the cranio-vertebral angle(CVA),truck angle(TA)sagittal shoulder posture angle(SSP)between not bearing schoolbags and bearing(except SSP of 10%BW weight and at low load placement)(P<0.05).The main effect of age,weight of schoolbag,carrying modeⅠandⅡwere significant on CVA,TA and coronal shoulder posture angle(CSP)(P<0.01),as well as SSP except that of age(P<0.05).The agewas of significant interacting effect with the weight of schoolbag,carrying modeⅠandⅡon CVA(P<0.05).The age and weight of schoolbag were of significant interaction effect with the carrying modeⅠon TA(P<0.05).The gender and carrying modeⅠ,the weight of schoolbags and carrying modes were both of significant effects on SSP(P<0.05).Moreover,when the schoolbag of lower weights was carried with lower load placement and fixing belt,little effect was exerted on children’s posture,and under the same carrying condition,younger kids had milder changes in their body posture.Conclusion Compared with not bearing schoolbags,the angles of most body postures tends to change if the weight increases up to 10%BW,and older kids(10~12 years)are more affected by the weight bearing.Such postural changes can be effectively reduced through lowering the load(around hips)or using chest belts.