Bazrgari B, Shirazi-Adl A
Division of Applied Mechanics, Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Québec, Canada.
Comput Methods Biomech Biomed Engin. 2007 Oct;10(5):351-60. doi: 10.1080/10255840701436974.
The spinal stability and passive-active load partitioning under dynamic squat and stoop lifts were investigated as the ligamentous stiffness in flexion was altered. Measured in vivo kinematics of subjects lifting 180 N at either squat or stoop technique was prescribed in a nonlinear transient finite element model of the spine. The Kinematics-driven approach was utilized for temporal estimation of muscle forces, internal spinal loads and system stability. The finite element model accounted for nonlinear properties of the ligamentous spine, wrapping of thoracic extensor muscles and trunk dynamic characteristics while subject to measured kinematics and gravity/external loads. Alterations in passive properties of spine substantially influenced muscle forces, spinal loads and system stability in both lifting techniques, though more so in stoop than in squat. The squat technique is advocated for resulting in smaller spinal loads. Stability of spine in the sagittal plane substantially improved with greater passive properties, trunk flexion and load. Simulation of global extensor muscles with curved rather than straight courses considerably diminished loads on spine and increased stability throughout the task.
随着脊柱在屈曲状态下韧带刚度的改变，研究了动态深蹲和弯腰提举时的脊柱稳定性以及被动 - 主动负荷分配情况。在脊柱的非线性瞬态有限元模型中规定了以深蹲或弯腰技术提起180 N重物的受试者的体内运动学测量值。运动学驱动方法用于临时估计肌肉力量、脊柱内部负荷和系统稳定性。有限元模型考虑了韧带脊柱的非线性特性、胸段伸肌的包裹情况和躯干动态特征，同时考虑了测量的运动学和重力/外部负荷。脊柱被动特性的改变在两种提举技术中均显著影响肌肉力量、脊柱负荷和系统稳定性，不过在弯腰提举中比在深蹲中影响更大。提倡采用深蹲技术，因为它会产生较小的脊柱负荷。随着被动特性、躯干屈曲和负荷的增加，脊柱在矢状面的稳定性显著提高。模拟具有弯曲而非直线走向的整体伸肌可显著减少脊柱上的负荷并在整个任务过程中提高稳定性。
