中文摘要：

目的针对背包重物集中放置在底部的传统集中式负重方式,研究将重物分散放置的非均匀负重方式对人体生理参数的影响。方法非均匀负重分布方式主要将背包空间按上、下、左、右分为4个空间,重物按1/2∶1/2、1/4∶3/4和3/4∶1/4三种比例放在左下和右上两个位置,剩余两个空间用对应体积大小的塑料泡沫填充。利用肌电测量系统和三维运动捕捉系统测量10名健康志愿者以1.1 m/s的速度在跑步机上负重10%自身体重行走30 min前后姿势、肌肉疲劳、心率和血压的变化,以及停止行走后0、5、10和15 min时肌电参数变化情况。结果右上位置负重增加明显,导致斜方肌肌肉疲劳上升和前倾角增大,相同背包重量下非均匀分布方式与传统负重方式对肌肉疲劳的影响区别不大,左下和右上重量比为3/4∶1/4的分布方式对身体姿势影响不明显。此外,将重物同比例左下右上放置比传统负重方式更有利于降低对心率和血压的影响。结论采取合理的重量分布方式可保证躯干姿势不受影响,同时有利于降低对心率和血压的影响。因此,背包设计可考虑重物交叉分布,且对等式分布质量。

英文摘要：

Objective To investigate the effects of unevenly-distributed backpack loads on human physiological parameters as compared to the traditional centrally-placed load at the backpack bottom. Methods For the unevenly-distributed load mode,the backpack was divided into four spaces including top right,top left,bottom right and bottom left. The loads were divided into two parts proportionally（ 1 /2 ∶ 1 /2,1 /4 ∶ 3 /4 and 3 /4 ∶ 1 /4） and placed at the bottom left and top right of the backpack,respectively. The remaining two spaces were filled with the plastic foam. Ten healthy volunteers performed 30-min walking trials on the treadmill at the speed of 1. 1 m / s with the backpack load equal to 10% body weight（ BW）. The changes of subjects＇ body posture,muscle fatigue,heart rate,blood pressure before and after the trial,as well as the electromyography（ EMG） changes at0,5,10,15 min after the trial were measured by the Bortec AMT-8 and the NDI Optotrak Certus. Results The muscle fatigue of right upper trapezius and forward-leaning angle increased as the loads at top right of the backpack increased. However,the muscle fatigue in the new mode of backpack load distribution showed no significant differences as compared to the traditional mode under the same backpack loads. The new mode with the load ratio of 3 /4∶ 1 /4 had no significant effects on posture. The new mode with the load ratio of 1 /2 ∶ 1 /2 could contribute to the decrease of heart rate and blood pressure as compared to the traditional mode. Conclusions Adopting a new and more reasonable load distribution mode can guarantee the body posture unaffected by the backpack loads,and decrease heart rate and blood pressure. Therefore,the cross and evenly distributed load mode is recommended for the backpack design.