Comparison of experimental and numerical muscle fiber conduction velocity (MFCV) distribution around the end-plate zone and fiber endings.
BACKGROUND
The distribution of muscle fiber conduction velocity (MFCV) estimated from surface myoelectric signals differs depending on the recording electrode locations. It is assumed in this study that the irregular values of MFCV may be estimated around the end-plate zone and the fiber endings due to effect of unique interference property of myoelectric signals, and its hypothesis is confirmed experimentally and numerically in consideration of the waveform characteristics of surface myoelectric signals.


METHODS
In experimental study, the surface myoelectric signals are recorded by array electrodes during voluntary isometric contraction in biceps brachii muscle. In the numerical study, the surface myoelectric signals in consideration of the interference property of some motor unit activities are calculated from the current dipole model which simulated the firing features of muscle fiber from end-plate zone to fiber endings. MFCV is estimated by the technique of cross-correlation. Maximum correlation coefficient (Rxy(Ts)) and amplitude ratio (AMPratio) are used to evaluate similarity and attenuation rate between traveling signals.


RESULTS
In both results of experimental and numerical studies, the MFCV significantly increase when both Rxy (Ts) and AMPratio decrease around the end-plate zone and fiber endings although three parameters denote constant values in the locations other than the end-plate zone and the fiber endings. The high correlativity is recognized between the experimental and numerical data for MFCV, Rxy (Ts), and AMPratio.


CONCLUSIONS
Therefore, it is demonstrated by experimental and theoretical studies that MFCV, Rxy(Ts), and AMPratio are influenced by irregular waveform properties depending on both positions of the end-plate and fiber endings.
Mito
Kazuyuki
K
Department of Systems Engineering, Faculty of Electro-Communications, The University of Electro-Communications, Tokyo, Japan. mito@se.uec.ac.jp
Kaneko
Kenichi
K
Makabe
Hitoshi
H
Takanokura
Masato
M
Sakamoto
Kazuyoshi
K
D000200:Action Potentials; D000328:Adult; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008959:Models, Neurological; D009045:Motor Endplate / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*