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首页> 外文期刊>Journal of Biomechanics >Lumbar spinal muscle activation synergies predicted by multi-criteria cost function.
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Lumbar spinal muscle activation synergies predicted by multi-criteria cost function.

机译：通过多标准成本函数预测的腰椎脊髓激活协同作用。

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The hypothesis that control of lumbar spinal muscle synergies is biomechanically optimized was studied by comparing EMG data with an analytical model with a multi-component cost function that could include (1) trunk displacements, (2) intervertebral displacements, (3) intervertebral forces; (4) sum of cubed muscle stresses, and (5) eigenvalues for the first two spinal buckling modes. The model's independent variables were 180 muscle forces. The 36 displacements of 6 vertebrae were calculated from muscle forces and the spinal stiffness. Calculated muscle activation was compared with EMG data from 14 healthy human subjects who performed isometric voluntary ramped maximum efforts at angles of 0 degrees, 45 degrees, 90 degrees, 135 degrees and 180 degrees to the right from the anterior direction. Muscle activation at each angle was quantified as the linear regression slope of the RMS EMG versus external force relationship, normalized by the maximum observed EMG.There was good agreement between the analytical model and EMG data for the dorsal muscles when the model included either minimization of intervertebral displacements or minimization of intervertebral forces in its cost function, but the model did not predict a realistic level of abdominal muscles activation. Agreement with EMG data was improved with the sum of the cubed muscle stresses added to the cost function. Addition of a cost function component to maximize the trunk stability produced higher levels of antagonistic muscle activation at low efforts than at greater efforts. It was concluded that the muscle activation strategy efficiently limits intervertebral forces and displacements, and that costs of higher muscle stresses are taken into account, but stability does not appear to be maximized. Trunk muscles are apparently not controlled solely to optimize any one of the biomechanical costs considered here.
机译：通过将EMG数据与具有多成分成本函数的分析模型进行比较，研究了生物力学优化控制腰椎脊髓协同作用的假说，该模型可能包括（1）躯干移位，（2）椎间移位，（3）椎间作用力; （4）立方体肌肉应力的总和，（5）前两个脊柱屈曲模式的特征值。该模型的自变量为180肌肉力量。根据肌肉力量和脊椎刚度计算出6个椎骨的36个位移。将计算出的肌肉激活与来自14位健康人类受试者的EMG数据进行比较，这些受试者在从右前方向向右0度，45度，90度，135度和180度的角度执行等距自愿倾斜最大努力。通过观察到的最大肌电图将每个角度的肌肉激活量化为RMS肌电图与外力关系的线性回归斜率，当该模型包括最小化肌电图时，分析模型与背肌的肌电图数据之间有很好的一致性椎间盘移位或椎间盘力量最小化的成本函数，但该模型并未预测出腹肌激活的实际水平。与EMG数据的一致性得到改善，增加了成本函数，增加了立方肌肉压力的总和。添加成本功能组件以使躯干稳定性最大化，与付出更大的努力相比，以较少的努力可以产生更高水平的拮抗肌肉激活。结论是，肌肉激活策略有效地限制了椎间作用力和位移，并且考虑了较高的肌肉压力的代价，但稳定性似乎没有得到最大化。显然不仅仅为了优化此处考虑的任何一种生物力学成本而对躯干肌肉进行控制。

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