Department of Orthopaedic Surgery, The University of Iowa, Iowa City, IA 52242, U.S.A.
J Electromyogr Kinesiol. 1995 Mar;5(1):37-44. doi: 10.1016/s1050-6411(99)80004-2.
Dynamic electromyography (EMG) utilizes either surface or fine-wire intramuscular electrodes. Ensemble-averaging of EMG profiles provides a convenient and commonly performed way to analyse these signals. This study was designed to evaluate the similarities of ensemble-averaged profiles of the two electrode types. We studied two muscles, the right vastus medialis (VM) and the left biceps femoris (BF), at freely-selected speeds of walking and jogging on a treadmill. Both electrodes were simultaneously attached to the subjects' legs. EMG signals were conditioned to produce linear envelopes. Pearson's correlation coefficients (r) and variance ratios (VR) were determined to assess the degree of similarity in the EMG profiles and the repeatability of the muscle activity, respectively. The ensemble-averaged signals reflect a high degree of pattern similarity as evidenced by high r values (usually greater than 0.90) for both muscles at both speeds. The low mean VRs indicate reasonable reproducibility for both electrode types; fine-wire electrodes in the BF and VM exhibit similar variability to surface electrodes. For the purpose of establishing relative profiles of activation during gait, ensemble-averaged surface and fine-wire signals are closely equivalent.
动态肌电图（EMG）使用表面或细金属丝肌内电极。EMG 谱的集合平均提供了一种方便且常用的分析这些信号的方法。本研究旨在评估两种电极类型的集合平均谱的相似性。我们在跑步机上以自由选择的步行和慢跑速度研究了两条肌肉，即右侧股直肌（VM）和左侧股二头肌（BF）。两种电极同时附着在受试者的腿上。对 EMG 信号进行调理以产生线性包络。分别使用 Pearson 相关系数（r）和方差比（VR）来评估 EMG 谱的相似程度和肌肉活动的可重复性。集合平均信号反映了高度的模式相似性，这表现在两种速度下两种肌肉的 r 值通常都大于 0.90。低平均 VR 表明两种电极类型都具有合理的可重复性；BF 和 VM 中的细金属丝电极表现出与表面电极相似的可变性。为了在步态过程中建立激活的相对谱，集合平均表面和细金属丝信号非常等效。
