Graduate School of Health Sciences, Sapporo Medical University, Japan; Research Fellow of Japan Society for the Promotion of Science, Japan.
Second Division of Physical Therapy, School of Health Sciences, Sapporo Medical University, Japan.
J Electromyogr Kinesiol. 2021 Feb;56:102493. doi: 10.1016/j.jelekin.2020.102493. Epub 2020 Nov 12.
This study examined the effect of hip flexion angle on the stiffness of the adductor longus (AL) muscle during isometric hip flexion. Seventeen men were recruited. Ten participants performed submaximal voluntary contraction at 0%, 25%, 50%, and 75% of maximal voluntary contraction (MVC) during isometric hip flexion after performing MVC at 0°, 40°, and 80° of hip flexion. Seven participants performed submaximal voluntary tasks during isometric hip extension in addition to hip flexion task. The shear modulus of the AL muscle was used as the index of muscle stiffness, and was measured using ultrasound shear-wave elastography during the tasks at each contraction intensity for each hip flexion angle. During hip flexion, the shear modulus of the AL muscle was higher at 0° than at 40° and 80° of hip flexion at each contraction intensity (p < 0.016). Conversely, a significant effect was not found among hip flexion angle during hip extension at 75% of MVC (p = 0.867). These results suggest that mechanical stress of the AL muscle may be higher at 0° of hip flexion during isometric hip flexion.
本研究旨在探讨等长髋关节屈曲时髋关节屈曲角度对内收肌（AL）硬度的影响。招募了 17 名男性。10 名参与者在进行 0°、40°和 80°髋关节屈曲的最大自主收缩（MVC）后，在等长髋关节屈曲时以 0%、25%、50%和 75%的最大自主收缩（MVC）进行亚最大自主收缩。7 名参与者除了髋关节屈曲任务外，还在髋关节伸展期间进行了亚最大自主任务。AL 肌肉的剪切模量用作肌肉硬度的指标，并在每个髋关节屈曲角度和每个收缩强度的任务期间使用超声剪切波弹性成像进行测量。在髋关节屈曲时，在每个收缩强度下，AL 肌肉的剪切模量在 0°时均高于 40°和 80°（p<0.016）。相反，在 MVC 的 75%时，髋关节伸展期间的髋关节屈曲角度没有发现显著影响（p=0.867）。这些结果表明，在等长髋关节屈曲时，AL 肌肉的机械应力在髋关节 0°时可能更高。
