Elucidation of the Motor unit firing behaviors in various human muscles

本研究的目的是阐明在随意等长力量消耗过程中，人体不同肌肉的运动单位放电行为。首先，对精密分解技术中的四股针状电极进行了改进。研制出能检测股内侧肌肌电信号的四股线电极。接下来，验证股内侧肌中运动单位的募集阈值、去募集阈值和放电率。运动单位的募集阈值与去募集阈值之间呈正相关。募集阈值与运动单位放电频率呈负相关。这些结果表明，“洋葱皮现象”的概念也适用于股内侧肌。

Purpose of the present research was to elucidate the motor unit firing behaviors in various human muscles during voluntary isometric force exertion. First, I improved the quadrifilar needle electrode which is used in the precision decomposition technique. As a result, the quadrifilar wire electrode which can detect the intra-muscular myoelectric signal of vastus medialis muscle was produced. Next, the recruitment threshold, the de-recruitment threshold, and the firing rate of the motor unit in the vastus medialis muscle were verified. The positive correlation was observed between the recruitment and de-recruitment threshold of the motor units. The negative correlation was observed between the recruitment threshold and the firing frequency of the motor units. These results indicate that the concept of the "Onion skin phenomenon" is also adapted in the vastus medialis muscle.