Mathematical equation of fusion index of tetanic contraction of skeletal muscles

作者：Watanabe S; Kitawaki T; Oka H^*

来源：Journal of Electromyography and Kinesiology, 2010, 20(2): 284-289.

DOI：10.1016/j.jelekin.2009.02.007

• Muscle force
• Fusion index
• Tetanic contraction
• Fiber type
• Twitch contraction

The fusion index (FI) is an index that can evaluate the tetanic progression of the skeletal muscles. Although the FI-frequency curve (FFC), which is obtained by changing the stimulation frequency, is greatly affected by muscle fiber type and fiber compositions, there are no reports of a mathematical equation that can express the FFC. In this study, the FFC was measured for the gastrocnemius, vastus intermedius, and soleus muscles of rats, and the mathematical equation (FFC-equation) was proposed. The FFC-equation (FI(f)) was proportional to the h-th power off, and was in inverse proportion to the sum of the h-th power of k and the h-th power off. f was the stimulation frequency, k was the stimulation frequency at 50% of FI, and h reflected the gradient of FFC. As a result, the approximated curve produced by the FFC-equation corresponded with the measured FFC. k reflected the fiber compositions and h represented the ratio of relaxation time to contraction time of the twitch contraction. The calcium ion fluctuation in muscle plasma may be described by the FFC-equation obtained from the experimental data.

• 出版日期2010-4