Tokyo Metropolitan University, Tokyo, Japan; Research Center in Back, Neck, Other Joint Pain and Human Performance (BNOJPH), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.
Toin University of Yokohama, Kanagawa, Japan.
J Biomech. 2019 Mar 6;85:1-5. doi: 10.1016/j.jbiomech.2018.12.010. Epub 2018 Dec 12.
The purpose of this study was to investigate the relationships between the ankle joint angle and maximum isometric force of the toe flexor muscles. Toe flexor strength and electromyography activity of the foot muscles were measured in 12 healthy men at 6 different ankle joint angles with the knee joint at 90 deg in the sitting position. To measure the maximum isometric force of the toe flexor muscles, subjects exerted maximum force on a toe grip dynamometer while the activity levels of the intrinsic and extrinsic plantar muscles were measured. The relation between ankle joint angle and maximum isometric force of the toe flexor muscles was determined, and the isometric force exhibited a peak when the ankle joint was at 70-90 deg on average. From this optimal neutral position, the isometric force gradually decreased and reached its nadir in the plantar flexion position (i.e., 120 deg). The EMG activity of the abductor hallucis (intrinsic plantar muscle) and peroneus longus (extrinsic plantar muscle) did not differ at any ankle joint angles. The results of this study suggest that the force generation of toe flexor muscles is regulated at the ankle joint and that changes in the length-tension relations of the extrinsic plantar muscle could be a reason for the force-generating capacity at the metatarsophalangeal joint when the ankle joint angle is changed.
本研究旨在探讨踝关节角度与趾屈肌最大等长力量之间的关系。12 名健康男性在坐姿下，膝关节呈 90°，6 个不同的踝关节角度下测量趾屈肌力量和足部肌肉的肌电图活动。为了测量趾屈肌的最大等长力量，受试者在趾夹测力计上施加最大力量，同时测量足底内在和外在肌肉的活动水平。确定了踝关节角度与趾屈肌最大等长力量之间的关系，平均而言，踝关节在 70-90°时等长力量达到峰值。从这个最佳中立位置开始，等长力量逐渐减小，并在跖屈位置（即 120°）达到最低点。在任何踝关节角度下，拇展肌（足底内在肌）和腓骨长肌（足底外在肌）的肌电图活动均无差异。本研究结果表明，趾屈肌的力量产生受踝关节调节，当踝关节角度改变时，外在足底肌的长度-张力关系的变化可能是跖趾关节产生力量的原因。
