Institute of Physical Education, Keio University, Kanagawa, Japan.
Eur J Appl Physiol. 2012 Jan;112(1):105-12. doi: 10.1007/s00421-011-1959-3. Epub 2011 Apr 17.
This study aimed to investigate the relationship between muscle hardness and muscle tension in terms of length-tension relationship. A frog gastrocnemius muscle sample was horizontally mounted on the base plate inside a chamber and was stretched from 100 to 150% of the pre-length, in 5% increments. After each step of muscle lengthening, electrical field stimulation for induction of tetanus was applied using platinum-plate electrodes positioned on either side of the muscle submerged in Ringer's solution. The measurement of muscle hardness, i.e., applying perpendicular distortion, was performed whilst maintaining the plateau of passive and tetanic tension. The relationship between normalised tension and normalised muscle hardness was evaluated. The length-hardness diagram could be created from the modification with the length-tension diagram. It is noteworthy that muscle hardness was proportional to passive and total tension. Regression analysis revealed a significant correlation between muscle hardness and passive and total tension, with a significant positive slope (passive tension: r = 0.986, P < 0.001; total tension: r = 0.856, P < 0.001). In conclusion, our results suggest that muscle hardness depends on muscle tension in most ranges of muscle length in the length-tension diagram.
本研究旨在探讨肌肉硬度与肌肉张力之间的关系，即长度-张力关系。将青蛙腓肠肌样本水平安装在腔体内的基板上，并在 5%的增量下从 100%至 150%的预长度进行拉伸。在肌肉每次伸长后，使用位于肌肉两侧的铂板电极在 Ringer 溶液中进行电刺激以引起强直收缩。在保持被动和强直张力平台的情况下，测量肌肉硬度，即施加垂直变形。评估归一化张力与归一化肌肉硬度之间的关系。可以通过修改长度-张力图来创建长度-硬度图。值得注意的是，肌肉硬度与被动张力和总张力成正比。回归分析显示肌肉硬度与被动张力和总张力之间存在显著相关性，斜率显著为正（被动张力：r = 0.986，P < 0.001；总张力：r = 0.856，P < 0.001）。总之，我们的结果表明，在长度-张力图的大多数肌肉长度范围内，肌肉硬度取决于肌肉张力。
