Rodriquez A A, Agre J C, Knudtson E R, Franke T M, Ng A V
Department of Rehabilitation Medicine, University of Wisconsin-Madison Medical School.
Muscle Nerve. 1993 Feb;16(2):188-92. doi: 10.1002/mus.880160212.
This study compared the acoustic (RMS-AMG) to electromyographic (RMS-EMG) signal, median frequency of EMG power spectrum (Fm), and quadriceps torque during isometric fatiguing contraction (FC) and recovery. Seven subjects were tested for strength (MVC) and then, on separate days, maintained 20%, 40%, or 80% MVC to exhaustion followed by MVC testing at regular intervals. Throughout FC, RMS-EMG significantly (P < 0.05) increased and Fm significantly (P < 0.05) decreased during all trials; RMS-AMG significantly (P < 0.05) increased only during the 20% and 40% trials. During recovery, MVC and RMS-EMG recovered most slowly after the 20% trial and most rapidly after the 80% trial; Fm and RMS-AMG recovered by 90 seconds after all trials. RMS-AMG reflects RMS-EMG during low but not high levels of FC. Recovery of strength is most depressed following FC at lower relative levels of torque. We conclude that RMS-AMG behaves differently than RMS-EMG, torque, and Fm during FC and recovery.
本研究比较了等长疲劳收缩（FC）及恢复过程中声学信号（均方根 - 平均肌电图，RMS - AMG）与肌电图信号（均方根 - 肌电图，RMS - EMG）、肌电图功率谱的中位频率（Fm）以及股四头肌扭矩。对7名受试者进行力量测试（最大随意收缩，MVC），然后在不同日期分别以20%、40%或80%的MVC强度持续收缩至力竭，随后定期进行MVC测试。在整个FC过程中，所有试验期间RMS - EMG均显著（P < 0.05）增加，Fm均显著（P < 0.05）降低；RMS - AMG仅在20%和40%强度试验期间显著（P < 0.05）增加。在恢复过程中，20%强度试验后MVC和RMS - EMG恢复最慢，80%强度试验后恢复最快；所有试验后90秒时Fm和RMS - AMG恢复。在低强度而非高强度FC期间，RMS - AMG反映RMS - EMG。在较低相对扭矩水平的FC后，力量恢复受抑制最明显。我们得出结论，在FC及恢复过程中，RMS - AMG的表现与RMS - EMG、扭矩和Fm不同。
