Department of Mechanical Engineering, Ecole Polytechnique, C.P. 6079, Succ centre-ville, Montreal, Quebec, H3C 3A7, Canada.
Ind Health. 2010;48(5):557-64. doi: 10.2486/indhealth.mswbvi-34.
Trunk biomechanical models play an indispensable role in predicting muscle forces and spinal loads under whole-body vibration (WBV) exposures. Earlier measurements on the force-motion biodynamic response (impedance, apparent mass) at the body-seat interface and vibration transmissibility (seat to head) have led to the development of different mechanical models. Such models could simulate the overall passive response and serve as an important tool for vehicle seat design. They cannot, however, evaluate physiological parameters of interest under the WBV. On the contrary, anatomical models simulating human's physiological characteristics can predict activities in muscles and their dynamic effects on the spine. In this study, a kinematics-driven nonlinear finite element model of the spine, in which the kinematics data are prescribed, is used to analyse the trunk response in seated WBV. Predictions of the active model (i.e., with varying muscle forces) as compared with the passive model (i.e., with no muscle forces) compared satisfactorily with measurements on vertical apparent mass and seat-to-head transmissibility biodynamic responses. Results demonstrated the crucial role of muscle forces in the dynamic response of the trunk. Muscle forces, while maintaining trunk equilibrium, substantially increased the compression and shear forces on the spine and, hence, the risk of tissue injury.
躯干生物力学模型在预测全身振动 (WBV) 暴露下的肌肉力和脊柱负荷方面发挥着不可或缺的作用。早期在体-座界面力-运动生物动力学响应（阻抗、表观质量）和振动传递率（座到头部）的测量导致了不同机械模型的发展。这些模型可以模拟整体被动响应，是车辆座椅设计的重要工具。然而，它们无法评估 WBV 下感兴趣的生理参数。相反，模拟人体生理特征的解剖模型可以预测肌肉活动及其对脊柱的动态影响。在这项研究中，使用运动学驱动的非线性有限元脊柱模型来分析坐姿 WBV 中的躯干响应，其中规定了运动学数据。主动模型（即肌肉力变化）的预测与被动模型（即无肌肉力）的预测与垂直表观质量和座到头部传递率生物动力学响应的测量结果相当。结果表明肌肉力在躯干动态响应中的重要作用。肌肉力在保持躯干平衡的同时，大大增加了脊柱上的压缩和剪切力，从而增加了组织损伤的风险。
