Objective: The main objective of this study was to assess the accuracy of bottom-up solution for three-dimensional (3D) inverse dynamics analysis of squat lifting using a 3D full body linked segment model. Least squares solution was used in this study as reference for assessment of the accuracy of bottom-up solution. Findings of this study may clarify how much the bottom-up solution can be reliable for calculating the joint kinetics in 3D inverse dynamics problems. Methods: Ten healthy males volunteered to perform squat lifting of a box with a load of one-tenth of their body weights. The joint moments were calculated using 110 reflective passive markers (46 anatomical markers and 64 tracking markers) and a 3D full body linked segment model. Ground reaction forces and kinematics data were recorded using a Vicon system with two parallel Kistler force plates. Three-dimensional Newton–Euler equations of motion with bottom-up and least squares solutions were applied to calculate joint moments. The peak and mean values of the joint moments were determined to check the quantitative differences as well as the time-to-peak value of the moment curves was determined to check the temporal differences between the two inverse dynamics solutions. Results: Significant differences (all P-values<0.05) between the two inverse dynamics solutions were detected for the peak values of the hip (right and left sides) and L5–S1 joint moments in the lateral anatomical direction as well significant differences (all P-values<0.05) were detected for the peak and mean values of the L5–S1 joint moment in all anatomical directions. Moreover, small differences (all RMSEs<0.01%) were detected between the two inverse dynamic solutions for the calculated lower body joint moments. Conclusions: The findings of this study clarified the disadvantages of the straightforward solutions and demonstrated that the bottom-up solution may not be accurate for more distal measures from the force plate (for hip and S1–L5) but it may be accurate for more proximal joints (ankle and knee) in 3D inverse dynamics analysis.

中文翻译：

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使用全身连接节段模型的深蹲举重 3D 逆向动力学分析方法比较

客观的：本研究的主要目的是评估使用 3D 全身链接节段模型对深蹲举重的三维 (3D) 逆动力学分析的自下而上解决方案的准确性。本研究使用最小二乘解作为自下而上解的准确性评估的参考。这项研究的结果可能会阐明自下而上的解决方案对于计算 3D 逆动力学问题中的联合动力学的可靠性有多大。方法：10 名健康男性自愿用其体重十分之一的负载进行深蹲举重。使用 110 个反射被动标记（46 个解剖标记和 64 个跟踪标记）和 3D 全身链接节段模型计算关节力矩。使用带有两个平行奇石乐测力台的 Vicon 系统记录地面反作用力和运动学数据。应用具有自下而上和最小二乘解的三维牛顿-欧拉运动方程来计算关节力矩。确定关节力矩的峰值和平均值以检查定量差异，并确定力矩曲线的峰值时间值以检查两个逆动力学解之间的时间差异。结果：显着差异（所有磷-价值观<0.05）在两个逆动力学解之间检测到臀部（右侧和左侧）的峰值和横向解剖方向的 L5-S1 关节力矩以及显着差异（所有磷-价值观<0.05）在所有解剖方向上检测到 L5-S1 关节力矩的峰值和平均值。此外，小的差异（所有RMSE<0.01%) 在计算的下肢关节力矩的两个逆动态解之间检测到。结论：这项研究的结果阐明了直接解决方案的缺点，并证明自下而上的解决方案对于测力台更远端的测量（髋关节和 S1-L5）可能不准确，但对于更近端的关节可能是准确的。脚踝和膝盖）在 3D 逆动力学分析中。