Seki Hiroyuki, Nagura Takeo, Suda Yasunori, Ogihara Naomichi, Ito Kohta, Niki Yasuo, Matsumoto Morio, Nakamura Masaya
1 Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan.
2 Department of Orthopedic Surgery, International University of Health and Welfare (IUHW) Mita Hospital, Tokyo, Japan.
Proc Inst Mech Eng H. 2018 Jun;232(6):637-640. doi: 10.1177/0954411918777267.
Axial loading of the human cadaver lower leg is known to generate eversion of the calcaneus and internal rotation of the tibia if the plantar surface of the foot does not slide on the floor. Such kinematic coupling between calcaneal eversion and internal tibial rotation has been described previously, but no studies have actually quantified the innate ability of the human foot to generate ground reaction moment around the vertical axis of the floor (vertical free moment) due to axial loading of the human cadaver lower leg. This study investigated the vertical free moment generated by eight cadaveric lower leg specimens loaded vertically with traction of the Achilles' tendon using a six-component force plate. The vertical free moments in all specimens were oriented toward the direction of internal rotation, and the mean magnitude of the vertical free moments was -1.66 N m when an axial load of 450 N was applied. A relatively large ground reaction moment can be applied to the body during walking due to the innate structural mobility of the foot. The structurally embedded capacity of the human foot to generate the vertical free moment may facilitate compensation of the moment generated around the vertical axis of the body during walking due to trunk rotation and leg swing.
已知如果足底不与地面滑动，对人体小腿进行轴向加载会导致跟骨外翻和胫骨内旋。跟骨外翻与胫骨内旋之间的这种运动学耦合先前已有描述，但尚无研究实际量化人体足部因人体小腿轴向加载而产生围绕地面垂直轴的地面反作用力矩（垂直自由力矩）的固有能力。本研究使用六分量测力板，对八具小腿标本通过跟腱牵引进行垂直加载时产生的垂直自由力矩进行了研究。所有标本中的垂直自由力矩均朝向内旋方向，当施加450 N的轴向载荷时，垂直自由力矩的平均大小为 -1.66 N·m。由于足部固有的结构灵活性，在行走过程中可对身体施加相对较大的地面反作用力矩。人体足部产生垂直自由力矩的结构固有能力可能有助于补偿行走过程中由于躯干旋转和腿部摆动而在身体垂直轴周围产生的力矩。
