Madinei Saman, Motabar Hossein, Ning Xiaopeng
a The Ergonomics Laboratory, Department of Industrial and Management Systems Engineering , West Virginia University , Morgantown , WV , USA.
Ergonomics. 2018 Oct;61(10):1364-1373. doi: 10.1080/00140139.2018.1489068. Epub 2018 Aug 13.
Sudden loading is a major risk factor for work-related lower back injuries among occupations involving manual material handling (MMH). The current study explored the effects of external weight configuration on trunk biomechanics and trunk rotational stiffness in the sagittal plane during sudden loading. Fifteen asymptomatic volunteers experienced sudden loadings using the same magnitude of weight (9 kg) with two different configurations (medially- or laterally-distributed) at three levels of height (low, middle and high). Results of this study showed that the medially distributed weight resulted in a significantly higher peak L5/S1 joint compression force (2861 N vs. 2694 N) and trunk rotational stiffness (2413 Nm/rad vs. 1785 Nm/rad) compared to the laterally distributed weight. It was concluded that when experiencing sudden loading, a more laterally distributed weight could increase the load's resistance to physical perturbations and alleviate spinal loading during sudden loading events. Practitioner summary: Increased trunk rotational stiffness and peak L5/S1 joint compression force were observed when undergoing a sudden load release of a medially distributed load compared to a laterally distributed load revealing a less stable hand load condition due to the reduced moment of inertia. The laterally distributed load could increase the load's resistance to physical perturbations and mitigate spinal loading during sudden loading events.
在涉及人工搬运物料（MMH）的职业中，突然加载是导致与工作相关的下背部损伤的主要风险因素。本研究探讨了外部重量配置对突然加载过程中矢状面内躯干生物力学和躯干旋转刚度的影响。15名无症状志愿者使用相同重量（9千克）、两种不同配置（内侧或外侧分布），在三个高度水平（低、中、高）下经历突然加载。本研究结果表明，与外侧分布的重量相比，内侧分布的重量导致L5/S1关节压缩力峰值（2861牛 vs. 2694牛）和躯干旋转刚度（2413牛·米/弧度 vs. 1785牛·米/弧度）显著更高。得出的结论是，在经历突然加载时，更外侧分布的重量可以增加负载对物理扰动的抵抗力，并减轻突然加载事件期间的脊柱负荷。从业者总结：与外侧分布的负载相比，内侧分布的负载突然释放时，观察到躯干旋转刚度增加和L5/S1关节压缩力峰值增加，这表明由于转动惯量减小，手部负载条件不太稳定。外侧分布的负载可以增加负载对物理扰动的抵抗力，并减轻突然加载事件期间的脊柱负荷。
