Movement and Sport Science, Department of Medicine, Faculty of Science, University of Fribourg, 1700 Fribourg, Switzerland.
J Electromyogr Kinesiol. 2013 Aug;23(4):892-8. doi: 10.1016/j.jelekin.2013.03.004. Epub 2013 Apr 10.
Conventional bipolar EMG provides imprecise muscle activation estimates due to possibly heterogeneous activity within muscles and due to improper alignment of the electrodes with the muscle fibers. Principal component analysis (PCA), applied on multi-channel monopolar EMG yielded substantial improvements in muscle activation estimates in pennate muscles. We investigated the degree of heterogeneity in muscle activity and the contribution of PCA to muscle activation estimates in biceps brachii (BB), which has a relatively simply parallel-fibered architecture. EMG-based muscle activation estimates were assessed by comparison to elbow flexion forces in isometric, two-state isotonic contractions in eleven healthy male subjects. Monopolar EMG was collected over the entire surface of the BB with about 63 electrodes. Estimation quality of different combinations of EMG channels showed that heterogeneous activation was found mainly in medio-lateral direction, whereas adding channels in the longitudinal direction added largely redundant information. Multi-channel bipolar EMG amplitude improved muscle activation estimates by 5-14% as compared to a single bipolar. PCA-processed monopolar EMG amplitude yielded a further improvement of (12-22%). Thus multi-channel EMG, processed with PCA, substantially improves the quality of muscle activation estimates compared conventional bipolar EMG in BB.
传统的双极肌电图由于肌肉内可能存在异质性活动以及电极与肌纤维的不当对准，提供的肌肉激活估计不准确。主成分分析（PCA）应用于多通道单极肌电图，可显著提高羽状肌的肌肉激活估计。我们研究了肌肉活动的异质性程度以及 PCA 对具有相对简单的平行纤维结构的肱二头肌（BB）肌肉激活估计的贡献。通过与 11 名健康男性在等长、双状态等张收缩中的肘部弯曲力进行比较，评估基于肌电图的肌肉激活估计。单极肌电图通过大约 63 个电极在 BB 的整个表面进行采集。不同肌电图通道组合的估计质量表明，异质性激活主要发生在中-外侧方向，而在纵向方向添加通道则增加了大量冗余信息。与单极双极相比，多通道双极肌电图幅度将肌肉激活估计提高了 5-14%。经过 PCA 处理的单极肌电图幅度进一步提高了（12-22%）。因此，与传统的双极肌电图相比，经过 PCA 处理的多通道肌电图可显著提高 BB 肌肉激活估计的质量。
