Granata K P, Marras W S
Biodynamics Laboratory, Ohio State University, Columbus, OH 43210, USA.
J Biomech. 1995 Nov;28(11):1309-17. doi: 10.1016/0021-9290(95)00003-z.
One of the continuing challenges in biomechanics has been to assess loading of the spine during dynamic lifting exertions. A model was developed to accurately simulate multi-dimensional spinal loads and trunk moments from measured muscle coactivity and external forces during free-dynamic lifting exertions. Model validity was demonstrated by comparing measured and predicted trunk extension moments. Its purpose was to examine realistic representations of lifting kinetics, kinematics, and dynamic trunk mechanics that may influence spinal loading, and to demonstrate that EMG-assisted modeling techniques can be applied to the analysis of free-dynamic exertions. Spinal loads and trunk moments were predicted from the muscle force vectors and external loads. Muscle tensile forces were determined from the product of normalized EMG data modulated to account for contractile dynamics, muscle cross sectional area, and muscle force per unit cross-sectional area. Model output was physiologically valid, i.e. average predicted muscle force per unit cross-sectional area of 50-65 N cm-2, and accurately predicted measured, dynamic, lifting moments, with an average R2 = 0.81 in the sagittal plane and R2 = 0.76 in the lateral plane. Results indicated that compressive and shear loading increased significantly with exertion load, lifting velocity, and trunk asymmetry.
生物力学领域持续存在的挑战之一是评估动态提举用力过程中脊柱的负荷情况。开发了一个模型，用于根据自由动态提举用力过程中测量到的肌肉协同活动和外力，精确模拟多维脊柱负荷和躯干力矩。通过比较测量到的和预测的躯干伸展力矩，证明了该模型的有效性。其目的是研究可能影响脊柱负荷的提举动力学、运动学和动态躯干力学的实际表现，并证明肌电图辅助建模技术可应用于自由动态用力分析。根据肌肉力向量和外部负荷预测脊柱负荷和躯干力矩。肌肉拉力由经调制以考虑收缩动力学、肌肉横截面积和单位横截面积肌肉力的标准化肌电图数据的乘积确定。模型输出在生理上是有效的，即单位横截面积的平均预测肌肉力为50 - 65 N/cm²，并且准确预测了测量到的动态提举力矩，矢状面的平均R² = 0.81，侧面的R² = 0.76。结果表明，压缩和剪切负荷随着用力负荷、提举速度和躯干不对称性的增加而显著增加。
