Objectives: To clarify the excitability of the central nervous system function via a difference in the feedback method, we examined the alterations in the duration of the silent period recorded from the opponens pollicis muscle during a precision motor task. This task involved isometric knee extension using visual feedback and verbal conduction. Design: Cross-sectional study with an A-B-A task-order design. Methods: 12 healthy adults (7 males and 5 females; mean age: 23.7 ± 2.1 years) participated in this study. SP was recorded from the opponens pollicis muscle during a precision motor task involving with isometric contraction during ipsilateral knee extension with constant torque by two kinds of feedback. The precision motor task was carried out as follows; Subjects maintained knee extension torque at a constant strength using the BIODEX SYSTEM 3 with 60° of knee flexion. The knee extension torque was set at 25% of individual maximum effort. We monitored the torque using two methods. The first method used subjects’ own visual feedback with gazing at the BIODEX screen (Task A). The second task featured torque adjustment by the examiner’s verbal instruction. Subjects’ eyes were bandaged to eliminate visual feedback (Task B). Silent period was recorded from the opponens pollicis muscle while subjects maintained ipsilateral isometric knee extension during an A-B-A task order. As a stimulus condition, a constant current rectangular wave with a frequency of 0.5 Hz and a duration of 0.2 ms, was added 16 times in the median nerve at the wrist with the intensity of supra-maximum, which maximal M wave was evoked. We compared the duration of silent period between tasks in each dominant and non-dominant side. Results: The duration of silent period on the dominant leg was 109.1 ± 5.2 ms (Task A), 105.2 ± 7.2 ms (Task B), and 107.6 ± 6.7 ms (Task A). And that on the non-dominant leg was 111.3 ± 6.1 ms (Task A), 105.9 ± 4.4 ms (Task B), and 109.3 ± 4.4 ms (Task A). There was no significant difference on the dominant leg side. However, during Task B on the non-dominant leg side, the duration of silent period was shortened (Tukey’s test, p = 0.01, 0.08). Conclusion: During less-skilled motor adjustment using the non-dominant leg, the motor control with verbal conduction and no visual feedback requires more afferent activation. In these cases, central nervous system function excitability associated with ipsilateral upper extremity increases, even if the task involves the lower extremity.

中文翻译：

---

在精密运动任务中，同侧膝盖伸展的等轴测收缩，Opponens Policis无声期。

目的：为了通过反馈方法的差异来阐明中枢神经系统功能的兴奋性，我们研究了精确运动任务中从对虾牙周肌记录的静默期持续时间的变化。该任务涉及使用视觉反馈和言语传导的等距膝盖伸展。设计：采用ABA任务顺序设计的横断面研究。方法：12名健康的成年人（7名男性和5名女性；平均年龄：23​​.7±2.1岁）参加了这项研究。通过精确的运动任务，通过两种反馈在同侧膝关节伸展等距收缩过程中等距收缩过程中记录了来自对手肌的肌肉中的SP。精密电机任务执行如下：受试者使用BIODEX SYSTEM 3以屈曲60°的膝盖保持恒定的力量伸展膝盖。膝盖伸展扭矩设定为个人最大力量的25％。我们使用两种方法监控扭矩。第一种方法是使用对象自己的视觉反馈并凝视BIODEX屏幕（任务A）。第二项任务是根据检查员的口头指示进行扭矩调节。用绷带包扎受试者的眼睛以消除视觉反馈（任务B）。在ABA任务指令期间，受试者的对侧骨膜肌肉保持沉默，而受试者保持同侧等距膝盖伸展。作为刺激条件，将频率为0.5 Hz，持续时间为0.2 ms的恒定电流矩形波以最大强度在腕部的正中神经中添加16次，引起最大的M波。我们比较了每个优势和非优势方面任务之间的静默期持续时间。结果：优势腿无声期的持续时间为109.1±5.2 ms（任务A），105.2±7.2 ms（任务B）和107.6±6.7 ms（任务A）。而在非主导腿上，该值是111.3±6.1 ms（任务A），105.9±4.4 ms（任务B）和109.3±4.4 ms（任务A）。优势腿侧无显着差异。但是，在任务B的非显性腿侧，静默期的持续时间缩短了（Tukey测试，p = 0.01，0.08）。结论：在使用非优势腿进行较不熟练的运动调节过程中，具有言语传导且无视觉反馈的运动控制需要更多传入的激活。在这些情况下，