We aimed to investigate the impact of time on fine-wire (fw) electromyography (EMG) signal amplitude, and to determine whether any attenuation is confounded by task type. Twenty healthy participants were instrumented with fw and surface (s) EMG electrodes at the biceps brachii bilaterally. Participants held a weight statically with one arm and with the other arm either repeated the same task following a maximum voluntary contraction (MVC) or repeated dynamic elbow flexion/extension contractions. Each task was repeated for 30 s every five minutes over two hours. EMG amplitude was smoothed and normalized to time = 0. Stable median power frequency of the s-EMG ruled out the confounding influence of fatigue. Repeated-measures ANCOVAs determined the effect of electrode type and time (covariate) on EMG amplitude and the confounding impact of task type. During the isometric protocol, fw-EMG amplitude reduced over time (p = 0.002), while s-EMG amplitude (p = 0.895) and MPF (p > 0.05) did not change. Fw-EMG amplitude attenuated faster during the dynamic than the isometric protocol (p = 0.008) and there was evidence that the MVC preceding the isometric protocol impacted the rate of decline (p = 0.001). We conclude that systematic signal attenuation of fw-EMG occurs over time and is more pronounced during dynamic tasks.

我们旨在研究时间对细线 (fw) 肌电图 (EMG) 信号幅度的影响，并确定是否有任何衰减被任务类型混淆。20 名健康参与者在双侧肱二头肌处安装了 fw 和表面 (s) EMG 电极。参与者用一只手臂静态举重，另一只手臂在最大自主收缩 (MVC) 或重复动态肘关节屈曲/伸展收缩后重复相同的任务。每个任务在两小时内每五分钟重复 30 秒。EMG 振幅被平滑并归一化为时间 = 0。s-EMG 的稳定中值功率频率排除了疲劳的混杂影响。重复测量 ANCOVA 确定了电极类型和时间（协变量）对 EMG 振幅的影响以及任务类型的混杂影响。在等距协议期间，fw-EMG 振幅随时间减小 (p = 0.002)，而 s-EMG 振幅 (p = 0.895) 和 MPF (p > 0.05) 没有变化。Fw-EMG 振幅在动态期间衰减速度比等长协议 (p = 0.008) 更快，并且有证据表明等长协议之前的 MVC 影响了下降率 (p = 0.001)。我们得出结论，fw-EMG 的系统信号衰减随时间发生，并且在动态任务期间更为明显。