Cescon C, Farina D, Gobbo M, Merletti R, Orizio C
Centro di Bioingegneria, Dip. di Elettronica, Politecnico di Torino, Torino, Italy.
Med Biol Eng Comput. 2004 Jan;42(1):121-7. doi: 10.1007/BF02351021.
To understand better the features of the mechanomyogram (MMG) with different force levels and muscle architectures, the MMG signals detected at many points along three muscles were analysed by the application of a linear array of MMG sensors (up to eight) over the skin. MMG signals were recorded from the biceps brachii, tibialis anterior and upper trapezius muscles of the dominant side of ten healthy male subjects. The accelerometers were aligned along the direction of the muscle fibres. One accelerometer was located over the distal muscle innervation zone, and the other six or seven accelerometers were placed over the muscle, forming an array of sensors with fixed distances between them. The array covered almost the entire muscle length in all cases. MMG signals detected from adjacent accelerometers had similar shapes, with correlation coefficients ranging from about 0.5 to about 0.9. MMG amplitude and characteristic spectral frequencies significantly depended on accelerometer location. The MMG amplitude was maximum at the muscle belly for the biceps brachii and the tibialis anterior. Higher MMG characteristic spectral frequencies were associated with higher amplitudes in the case of the biceps brachii, whereas the opposite was observed for the tibialis anterior muscle. In the upper trapezius, the relationship between characteristic spectral frequencies, MMG amplitude and contraction force depended on the accelerometer location. This suggested that MMG spectral features do not only reflect the mechanical properties of the recruited muscle fibres but depend on muscle architecture and motor unit territorial distribution. It was concluded that the location of the accelerometer can have an influence on both amplitude and spectral MMG features, and this dependence should be considered when MMG signals are used for muscle assessment.
为了更好地理解不同力量水平和肌肉结构下的肌动图（MMG）特征，通过在皮肤上应用线性排列的MMG传感器（最多八个），对沿着三块肌肉多个点检测到的MMG信号进行了分析。记录了十名健康男性受试者优势侧肱二头肌、胫骨前肌和上斜方肌的MMG信号。加速度计沿肌肉纤维方向排列。一个加速度计位于肌肉远端神经支配区上方，另外六个或七个加速度计放置在肌肉上，形成一个传感器阵列，它们之间有固定的距离。在所有情况下，该阵列几乎覆盖了整个肌肉长度。从相邻加速度计检测到的MMG信号形状相似，相关系数在约0.5至约0.9之间。MMG幅度和特征频谱频率显著取决于加速度计的位置。肱二头肌和胫骨前肌在肌腹处MMG幅度最大。在肱二头肌的情况下，较高的MMG特征频谱频率与较高的幅度相关，而胫骨前肌则观察到相反的情况。在上斜方肌中，特征频谱频率、MMG幅度和收缩力之间的关系取决于加速度计的位置。这表明MMG频谱特征不仅反映了募集的肌纤维的力学特性，还取决于肌肉结构和运动单位的区域分布。得出的结论是，加速度计的位置会对MMG的幅度和频谱特征产生影响，在将MMG信号用于肌肉评估时应考虑这种依赖性。
