DEALING WITH SKIN MOTION AND WOBBLING MASSES IN INVERSE DYNAMICS
DEALING WITH SKIN MOTION AND WOBBLING MASSES IN INVERSE DYNAMICS
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DOI：
10.1142/s0219519403000831
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发表时间：
2003-09-01
影响因子：
0.8
通讯作者：
Blickhan, Reinhard
中科院分区：
文献类型：
--
作者：
Guenther, Michael;Sholukha, Viktor A.;Blickhan, Reinhard
逆动力学是生物力学中的一种标准分析方法，用于根据测量的外力和节段运动学来重建内部驱动力和扭矩的时间历程。在此过程中导致分析伪影的不一致性的主要来源是皮肤标记物和软组织运动。关节扭矩中这些潜在的人为高频波动可能会成为关于肌肉活动的（误导性）假设的错误基础。在此我们提出减少这些误差的技术。在本研究的两个部分中，均获取了高速视频和测力台数据。在一部分中，对69组人类赤脚跑步的序列进行了采样，随后对支撑腿进行了逆动力学分析。矢状面内髋关节扭矩的时间历程作为动态分析伪影的敏感“探测器”。我们表明，通过使用骨骼刚性（恒定的节段长度）和骨骼轮廓（膝关节正面边缘）信息处理运动学数据，可以显著减少最重要的误差——尤其是膝关节标记物的皮肤相对于骨骼的运动。此外，在逆动力学模型中显著忽略起始的软组织动力学在分析过程中引入了另一种不一致性。因此，在本研究的第二部分中，确定了14个跳跃序列的软组织运动学。这些数据提供了一组摆动质量与骨骼的耦合参数，可用于逆动力学模型。使用符合实际的骨骼运动学主要可避免腿部加速度情形中的相位偏移，从而避免整个接触期间髋关节扭矩的人为波动。在人类跑步中，考虑软组织动力学会主要影响冲击阶段髋关节扭矩的计算时间。
Inverse dynamics is a standard analysis in biomechanics to reconstruct time histories of internal driving forces and torques from measured external forces and segmental kinematics. The main sources of inconsistency leading to analytical artefacts in this process are skin marker and soft tissue motion. These potentially artificial high frequency fluctuations in the joint torques may serve as an erroneous basis of (misleading) assumptions with respect to muscular activity. Here we suggest techniques to reduce these errors. In both parts of this study, high-speed video and force platform data were acquired. In one part, 69 sequences of human barefoot running were sampled followed by an inverse dynamic analysis of the stance leg. The time history of the hip joint torque in the sagittal plane served as a sensitive "detector" of dynamic analysis artefacts. We show that the most important error - the relative skin to bone motion especially of the knee marker - can be reduced significantly by processing kinematic data using bone rigidity (constant segment lengths) and bony contour (frontal knee edge) information. Further on, neglecting significantly initiated soft tissue dynamics in the inverse dynamic model introduces another inconsistency in the analytical process. Therefore, in a second part of this study, soft tissue kinematics from 14 jumping sequences were identified. These data provided a set of coupling parameters of wobbling masses to the bone that were ready to be implemented in the inverse dynamic model. Using realistic bone kinematics mainly avoids phase shifts in the acceleration scenario within the leg, and thus artifical hip torque fluctuations within the whole contact period. In human running, accounting for soft tissue dynamics mainly affects the calculated timing of the hip joint torque during the impact phase.