Southgate Dominic F L, Cleather Daniel J, Weinert-Aplin Robert A, Bull Anthony M J
Bioengineering Department, Imperial College London, UK.
Proc Inst Mech Eng H. 2012 Sep;226(9):660-9. doi: 10.1177/0954411912439284.
Soft tissue artifacts during motion capture can lead to errors in kinematics and incorrect estimation of joint angles and segment motion. The aim of this study was to evaluate the effect of shank segment axial rotation and knee rotator muscle bounds on predicted muscle and joint forces in a musculoskeletal model of the lower limb. A maximal height jump for ten subjects was analysed using the original motion data and then modified for different levels of internal and external rotation, and with the upper force bound doubled for five muscles. Both externally rotating the shank and doubling the muscle bounds increased the ability of the model to find a solution in regions of high loading. Muscle force levels in popliteus and tensor fascia latae showed statistically significant differences, but less so in plantaris, sartorius or gracilis. The shear and patellofemoral joint forces were found to be significantly affected by axial rotation during specific phases of the motion and were dependent on the amount of rotation. Fewer differences were observed when doubling the muscle bounds, except for the patellofemoral force and plantaris and sartorius muscle force, which were significantly increased in many of the jump phases. These results give an insight into the behaviour of the model and give an indication of the importance of accurate kinematics and subject-specific geometry.
运动捕捉过程中的软组织伪影会导致运动学误差以及关节角度和节段运动的估计错误。本研究的目的是评估小腿节段轴向旋转和膝关节旋转肌约束对下肢肌肉骨骼模型中预测的肌肉和关节力的影响。使用原始运动数据对十名受试者的最大高度跳跃进行了分析，然后针对不同程度的内旋和外旋进行了修改，并将五块肌肉的上力约束加倍。小腿外旋和肌肉约束加倍均提高了模型在高负荷区域找到解决方案的能力。腘肌和阔筋膜张肌的肌肉力水平显示出统计学上的显著差异，但跖肌、缝匠肌或股薄肌的差异较小。在运动的特定阶段，剪切力和髌股关节力被发现受到轴向旋转的显著影响，并且取决于旋转量。当肌肉约束加倍时，观察到的差异较少，除了髌股力以及跖肌和缝匠肌的肌肉力在许多跳跃阶段显著增加。这些结果深入了解了模型的行为，并表明了精确运动学和个体特异性几何形状的重要性。
