Less is more: high pass filtering, to remove up to 99% of the surface EMG signal power, improves EMG-based biceps brachii muscle force estimates
Less is more: high pass filtering, to remove up to 99% of the surface EMG signal power, improves EMG-based biceps brachii muscle force estimates
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DOI：
10.1016/j.jelekin.2003.10.005
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发表时间：
2004-06-01
影响因子：
2.5
通讯作者：
Brown, SHM
中科院分区：
文献类型：
--
作者：
Potvin, JR;Brown, SHM
通常假设原始表面EMG（sEMG）应该以10-30 Hz的截止进行高通滤波，以在后续处理以估计肌肉力量之前去除运动伪影。本研究的目的是探索在试图估计准确的肌肉力量时过滤掉大部分原始sEMG信号的好处。25名受试者进行了研究，因为他们进行快速静态，不等张收缩的肱二头肌。根据腕部记录的力估计肱二头肌力（作为最大值的百分比）。使用迭代方法处理来自肱二头肌的sEMG，使用具有一阶和六阶滤波器的逐渐增大的高通截止频率（20-440 Hz，以30 Hz为步长）以及信号白化，以确定对基于EMG的肱二头肌力估计的准确性的影响。结果表明，去除高达99%的原始sEMG信号功率导致二头肌力估计的显着和实质性的改善。这些发现挑战了先前的假设，即在估计肌肉力量时应使用约20和500 Hz之间的原始sEMG信号功率。为了力预测的目的，似乎小得多的高频带的sEMG频率可以与力相关联，并且频谱的其余部分与力估计几乎没有相关性。(C)2003 Elsevier Ltd.保留所有权利。
It, is generally assumed that raw surface EMG (sEMG) should be high pass filtered with cutoffs of 10-30 Hz to remove motion artifact before subsequent processing to estimate muscle force. The purpose of the current study was to explore the benefits of filtering out much of the raw sEMG signal when attempting to estimate accurate muscle forces. Twenty-five subjects were studied as they performed rapid static, anisotonic contractions of the biceps brachii. Biceps force was estimated (as a percentage of maximum) based on forces recorded at the wrist. An iterative approach was used to process the sEMG from the biceps brachii, using progressively greater high pass cutoff frequencies (20-440 Hz in steps of 30 Hz) with first and sixth order filters, as well as signal whitening, to determine the effects on the accuracy of EMG-based biceps force estimates. The results indicate that removing up to 99% of the raw sEMG signal power resulted in significant and substantial improvements in biceps force estimates. These findings challenge previous assumptions that the raw sEMG signal power between about 20 and 500 Hz should used when estimating muscle force. For, the purposes of force prediction, it appears that a much smaller, high band of sEMG frequencies may be associated with force and the remainder of the spectrum has little relevance for force estimation. (C) 2003 Elsevier Ltd. All rights reserved.