Okamura Kazunori, Kanai Shusaku, Oki Sadaaki, Tanaka Satoshi, Hirata Naohisa, Sakamura Yoshiaki, Idemoto Norikatsu, Wada Hiroki, Otsuka Akira
Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Japan.
Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan.
J Phys Ther Sci. 2017 Jun;29(6):1001-1005. doi: 10.1589/jpts.29.1001. Epub 2017 Jun 7.
[Purpose] There are no reliable evidences that the weakening of intrinsic foot muscles causes the decrease of the medial longitudinal arch (MLA) height. The purpose of this study was to confirm whether the fatigue of intrinsic foot muscles decrease the MLA height during standing and gait using 3D motion analysis system. [Subjects and Methods] Twenty healthy male subjects participated in this study. Foot kinematics was measured using an Oxford Foot Model before and after fatigue-inducing exercises of the abductor hallucis and flexor hallucis brevis muscles. [Results] Following fatigue-inducing exercise, in both standing and gait, the MLA height did not decrease but slightly increased. In addition, the reduction of a rear foot eversion angle was noted. [Conclusion] Fatigue of the abductor hallucis and flexor hallucis brevis muscles did not cause a change associated with collapsing of the MLA during both standing and gait. This suggested that the MLA support force from these muscles would be compensated by other MLA support structures, such as extrinsic foot muscles.
[目的] 目前尚无可靠证据表明足部内在肌减弱会导致内侧纵弓（MLA）高度降低。本研究的目的是使用三维运动分析系统，确认足部内在肌疲劳是否会在站立和步态过程中降低MLA高度。[对象与方法] 20名健康男性受试者参与了本研究。在对拇展肌和拇短屈肌进行疲劳诱导运动前后，使用牛津足部模型测量足部运动学参数。[结果] 在疲劳诱导运动后，无论是站立还是步态过程中，MLA高度均未降低，反而略有增加。此外，还观察到后足外翻角度减小。[结论] 拇展肌和拇短屈肌的疲劳在站立和步态过程中均未引起与MLA塌陷相关的变化。这表明这些肌肉对MLA的支撑力将由其他MLA支撑结构（如足部外在肌）进行代偿。
