The supplementary datasets of the study of free moment Induced by oblique transverse tarsal joint: investigation by constructive approach

The human foot provides numerous functions that let humans deal with
various environments. Recently, study of the structure of the
human foot and adjustment of an appropriate reaction force and vertical
free moment during bipedal locomotion has gained
attention. However, little is known about the mechanical
(morphological) contribution of the foot structure to the reaction force
and free moment. It is difficult to conduct a comparative experiment to
investigate the contribution systematically by using conventional methods
with human and cadaver foot experiments. This study focuses on
the oblique transverse tarsal joint (TTJ) of the human foot, whose
mechanical structure can generate appropriate free moments. We
conduct comparative experiments with a rigid foot, a non-oblique joint
foot (i.e., mimicking only the flexion/extension of the midfoot), and an
oblique joint foot. Axial loading and walking experiments were
conducted with these feet. The axial loading experiment
demonstrated that the oblique foot generated free moment in the direction
of internal rotation, as observed in the human foot. The walking
experiment showed that the magnitude of the free moment generated with the
oblique foot is significantly lower than that with the rigid foot during
the stance phase. Using this constructive approach, the present study
demonstrated that the oblique axis of the TTJ can mechanically generate
free moments. This capacity might affect the transverse motion of bipedal
walking.

人类足部具备多样功能，可帮助人类适配各类环境。近年来，针对人类足部结构的研究，以及双足步行（bipedal locomotion）过程中适宜反力（reaction force）与垂直自由力矩（free moment）的调控策略，愈发受到关注。然而，目前对于足部结构在力学（形态学）层面对反力与自由力矩的贡献机制，仍缺乏深入认知。若采用传统的人体与尸体足部实验方法，难以系统开展对比实验以探究该贡献机制。本研究聚焦于人类足部的斜行跗横关节（oblique transverse tarsal joint, TTJ），该关节的力学结构可产生适配需求的自由力矩。我们分别构建了刚性足、非斜行关节足（即仅模拟中足屈伸运动的模型）以及斜行关节足三种足部实验模型，并开展对比实验。针对上述三种模型，我们分别开展了轴向加载实验与步行实验。轴向加载实验结果显示，斜行足可产生与人类足部一致的内旋方向自由力矩。步行实验结果表明，在步行支撑相（stance phase）阶段，斜行足产生的自由力矩幅值显著低于刚性足。通过此构建式研究方法，本研究证实，跗横关节的斜行轴可在力学层面产生自由力矩，该能力或许会对双足步行的横向运动产生影响。