Chino Kentaro, Takahashi Hideyuki
1 Japan Institute of Sports Sciences.
J Appl Biomech. 2018 Jun 1;34(3):169-174. doi: 10.1123/jab.2017-0121. Epub 2018 May 25.
Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, the authors assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, and 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggests that muscle stiffness of the MG would not be a prominent factor in determining passive ankle joint stiffness and the sex-related difference in the joint stiffness.
被动踝关节僵硬受关节内外所有结构的影响，且男性比女性更明显。局部肌肉僵硬可通过超声剪切波弹性成像进行评估，肌肉结构如肌束长度和羽状角可通过B型超声测量。因此，作者在考虑肌肉结构个体差异的情况下，评估了腓肠肌内侧头（MG）的局部肌肉僵硬情况，并研究了肌肉僵硬与被动踝关节僵硬的关系以及关节僵硬的性别差异。在16名男性和17名女性中，于跖屈10°和20°、中立解剖位置以及背屈10°和20°时评估MG的局部肌肉僵硬情况。在这些关节位置测量MG的肌束长度和羽状角。通过踝关节角度-扭矩关系确定被动踝关节僵硬程度。即使考虑肌肉结构，MG局部肌肉僵硬与被动踝关节僵硬也无显著相关性，且未显示出明显的性别差异。这一发现表明，MG的肌肉僵硬并非决定被动踝关节僵硬及关节僵硬性别差异的主要因素。
