Knapik J J, Harper W, Crowell H P, Leiter K, Mull B
US Army Research Laboratory, Human Research and Engineering Directorate, Aberdeen Proving Ground, MD 21010, USA.
Ergonomics. 2000 May;43(5):639-52. doi: 10.1080/001401300184305.
Transporting a casualty on a stretcher is a common task for medical and military personnel. Stretchers are usually carried by hand, but distributing the load to other parts of the body may have advantages. To examine alternative carriage methods, 11 soldiers walked on a treadmill at 4.8 km/h while performing two-person carries of a stretcher containing an 80-kg manikin. In separate trials, soldiers carried the stretcher using: (1) hand carriage, (2) shoulder straps, (3) a specially designed harness that allowed load shifting between the hips and shoulders (hip-shoulder system), and (4) a clip that fitted on the belt of standard military load carrying equipment (LCE) and placed the stretcher mass mainly on the hips. With each system, subjects walked until volitional fatigue or 30 min. While walking, expired gases and heart rates were obtained and subjects rated their perceived exertion (Borg Scale). At the conclusion of all four trials, subjects rated each system on a number of subjective measures. Results showed that average (+/- SD) carriage times were 2.7+/-1.4, 14.5+/-8.3, 25.4+/-8.1, and 21.7+/-9.9 min with the hand, shoulder, hip-shoulder and LCE systems respectively (p<0.01). Hand carriage resulted in considerably more cardiorespiratory stress (higher heart rate and minute ventilation, p<0.05) than the other three systems, but there were few consistent differences among the other three systems. Perceived exertion in the upper body was less with the hip-shoulder and LCE systems than with the other two systems (p<0.05). Subjects preferred the hip-shoulder and LCE systems overall and for specific subjective characteristics such as comfort, ease of use and stability (p<0.01). These data indicate that moving the stretcher load from the hands and placing that load on the shoulders and/or hips results in improved performance, reduced cardiorespiratory stress and favourable subjective evaluations. Further developmental work should focus on the hip-shoulder and LCE systems.
用担架运送伤员是医疗人员和军事人员的一项常见任务。担架通常由人力搬运，但将负载分散到身体的其他部位可能有好处。为了研究其他搬运方法，11名士兵以4.8公里/小时的速度在跑步机上行走，同时两人抬着一副装有80公斤人体模型的担架。在不同的试验中，士兵们使用以下方式抬担架：(1) 用手搬运；(2) 使用肩带；(3) 一种特殊设计的背带，可使负载在臀部和肩部之间转移（臀部-肩部系统）；(4) 一个安装在标准军事负载携带装备（LCE）腰带上的夹子，将担架的重量主要放在臀部。对于每种系统，受试者一直行走至自愿疲劳或30分钟。行走过程中，采集呼出气体和心率数据，并让受试者对其主观用力程度进行评分（Borg量表）。在所有四项试验结束时，受试者根据多项主观指标对每种系统进行评分。结果显示，使用手部、肩部、臀部-肩部和LCE系统时，平均（±标准差）搬运时间分别为2.7±1.4、14.5±8.3、25.4±8.1和21.7±9.9分钟（p<0.01）。与其他三种系统相比，手部搬运导致的心肺压力明显更大（心率和分钟通气量更高，p<0.05），但其他三种系统之间几乎没有一致的差异。与其他两种系统相比，臀部-肩部和LCE系统使上半身的主观用力程度更低（p<0.05）。总体而言，受试者更喜欢臀部-肩部和LCE系统，以及在舒适度、易用性和稳定性等特定主观特征方面（p<0.01）。这些数据表明，将担架负载从手部转移到肩部和/或臀部可提高性能、减轻心肺压力并获得良好的主观评价。进一步的研发工作应聚焦于臀部-肩部和LCE系统。
