Jäger M, Luttmann A
Ergonomics. 1989 Jan;32(1):93-112. doi: 10.1080/00140138908966070.
A dynamic biomechanical human model is presented which allows the quantification of mechanical parameters such as torque, compressive and shear forces, and pressure at the lumbar intervertebral discs. The human model comprises a total of 19 body segments. Various trunk flexions can be analysed due to the provision of 5 joints at the level of the 5 lumbar intervertebral discs. The influence of intraabdominal pressure on spinal load is considered. The inclusion of the influences of gravity and inertia permits the analysis of both static body postures and dynamic body movements. Since the model is 3-dimensional, the lumbar stress can be calculated during both symmetrical tasks in the median sagittal plane as well as during non-symmetrical ones. The influences on spinal stress of trunk inclination and the position of an external load relative to the body are quantified for various load weights up to 50 kg. The torque at the lumbo-sacral joint L5-S1 lies, dependent on posture and load lever-arm, within the range between 0 and 500 Nm; the compressive force on L5-S1 lies within the range between 0.4 and 10 kN, and the shear force at L5-S1 between 0.2 and 0.9 kN. The influences of lift velocity and jerky movement on lumbar stress are quantified. Simulated humpback and hollow-back postures are studied. The compressive forces at the 5 lumbar intervertebral discs are compared. The validity of the model is examined by comparing the model calculations with the intradiscal pressure measurements taken from the literature. Strength tests on lumbar intervertebral discs and vertebrae are collated from the literature in order to assess the lumbar stress during load lifting. The lumbar ultimate compression strength varies within a wide range. The mean value for a total of 307 lumbar segments amounts to 4.4 kN, the standard deviation to 1.9 kN. In conclusion, lumbar compressive force values during lifting fall within the same range as the strength values for the human lumbar spine.
本文提出了一种动态生物力学人体模型，该模型能够对诸如扭矩、压缩力和剪切力以及腰椎间盘压力等力学参数进行量化。人体模型总共包含19个身体节段。由于在5个腰椎间盘水平设置了5个关节，因此可以分析各种躯干屈曲情况。考虑了腹内压对脊柱负荷的影响。纳入重力和惯性的影响后，可以分析静态身体姿势和动态身体运动。由于该模型是三维的，因此可以在正中矢状面的对称任务以及非对称任务期间计算腰椎应力。对于高达50 kg的各种负载重量，量化了躯干倾斜度和外部负载相对于身体的位置对脊柱应力的影响。腰 - 骶关节L5 - S1处的扭矩，取决于姿势和负载力臂，在0至500 Nm范围内；L5 - S1处的压缩力在0.4至10 kN范围内，L5 - S1处的剪切力在0.2至0.9 kN范围内。量化了提升速度和急促动作对腰椎应力的影响。研究了模拟的驼背和凹背姿势。比较了5个腰椎间盘处的压缩力。通过将模型计算结果与文献中获取的椎间盘内压力测量值进行比较，检验了模型的有效性。从文献中整理了腰椎间盘和椎骨的强度测试，以评估举重过程中的腰椎应力。腰椎极限压缩强度在很宽的范围内变化。总共307个腰段的平均值为4.4 kN，标准差为1.9 kN。总之，举重过程中的腰椎压缩力值与人类腰椎的强度值处于同一范围内。
