双肩背负系统影响因素研究

Research on the influence factors of the carrying system

目的研究人体在进行双肩背部负重行走时，不同实验组合下背部主肌肉群的表面肌电信号和主观疲劳评价，探讨人体肌肉功能状态和疲劳特性。方法于2017年10—12月，选择10名大学生志愿者进行双肩背负作业实验，受测者分别在不同肩带宽度、不同背负重量以及不同腰垫软硬度组合下行走，共需完成12组实验，每组持续时间15min，工间休息时间为30min。而后，分别测定他们在实验过程时上斜方肌（UT）、竖脊肌（ES）的表面肌电信号及完成每组实验间休息时的主观疲劳评价，对其时域评价指标（平均振幅，aEMG）与频域评价指标（中位频率，MF）以及主观测试得到的数据进行处理与分析。结果负重大小和肩带宽度对人体疲劳程度有影响，差异有统计学意义（P〈0．01），腰垫软硬程度的变化对于人体疲劳程度无影响，差异无统计学意义（P〉0．05）；负重大小与肩带宽度的组合具有交互效应（P〈0．01），负重大小与肩带宽度、腰垫软硬3者的组合不具有交互效应（P〉0．05）。对于背包背负系统而言，10％重量、50mm宽度肩带的背负组合是缓解疲劳效果最好的组合。主观测试表明受试者主观感受肌肉疲劳度也与重量宽度相关，与肌电实验结果一致。结论实验结果表明人体在进行双肩背负行走时，使用10％重量与50mm宽度肩带的组合有利于缓解肌肉疲劳，双肩背负行走更易引起竖脊肌疲劳。

Objective To investigate surface electromyography signal（sEMG） of the major back muscle group and subjective fatigue assessment under different experimental combinations during walk with weight on both shoulders, as well as the functional status and fatigue property of human muscles. Methods From October to December, 2017, 10 college students were recruited to participate in shoulder weight-bearing work and walk under the combinations of different shoulder strap widths, weights, and hardness of waist cushion. The subjects were required to complete 12 sets of experiments, with each set lasting for 15 minutes, and the rest time between work was 30 minutes. The sEMG signals of the upper trapezius and the erector spinae were measured during the experiment, and subjective fatigue assessment was performed during rest. The time domain evaluation index （average amplitude, aEMG）, the frequency domain evaluation index （median frequency, MF）, and the data of subjective assessment were processed and analyzed. Results Weight and shoulder strap width had a significantly effect on fatigue （P〈0.01）, and the change in the hardness of waist cushion had no significant effect on fatigue （P〉0.05）. There was an interaction effect between weight and shoulder strap width （P〈0.01）, and there was no interaction effect between weight, shoulder strap width, and hardness of waist cushion （P〉0.05）. For the backpack carrying system, the combination of 10% weight and 50 mm shoulder strap width was the best one for relieving fatigue. The subjective test also showed that subjective feelings of muscle fatigue were associated with the weight and width, which was consistent with sEMG results. Conclusion The results of this experiment show that the combination of 10% weight and 50 mm shoulder strap width can help to relieve muscle fatigue during walk with weight on both shoulders, and weight-bearing walking is more likely to cause the fatigue of the erector spinae.