Conductivity of High and Low Frequency Components of Monopolarily Recorded Surface Nyoelectric Signals from m. Biceps Brachii.
- VernacularTitle:振幅スペクトラムと相互相関法からみた上腕二頭筋表面筋電位の特徴
- Author:
MIFUYU KAMO
;
CSUKAS ATTILA
;
SHIGERU MORIMOTO
- Publication Type:Journal Article
- Keywords:
Surface myoelectric signal;
m. biceps brachii;
Cross-correlation;
Conductivity;
Amplitude spectrum
- From:Japanese Journal of Physical Fitness and Sports Medicine
2001;50(4):501-512
- CountryJapan
- Language:Japanese
-
Abstract:
We applied Fast Fourier Transform to monopolarily recorded surface myoelectric signals from m. biceps brachii to obtain the turning frequency (TF) at which the signals divide into high and low frequency components. Then using the TF as a cut-off point, the raw myoelectric signals were divided into high frequency component (HFC) and low frequency component (LFC) .
1) TF values were constant at every recording position along muscle fibers. And there was no considerable relationship between developed tensions and TF values.
2) Cross-correlation analysis was done to obtain the phase relationship between LFCs, and between HFCs at four different recording positions along muscle fibers. LFCs appeared in phase in all combinations below the tension of 10%MVC and also in HFCs. Above 20%MVC, LFCs represented the time delay depending upon the electrode distance in six subjects. The conduction velocity calculated from the relationship between time delay and distance in LFC was too high (16.1 m·s-1-33.3 m·s-1) compared with the muscle fiber and/or motor unit conduction velocity. But LFCs in other subjects remained in phase. HFCs showed no considerable relationship above 20%MVC in six subjects, while other subjects remained in phase between HFCs.
The present results differ from the recent investigation in m. vastus medialis (Kamo & Morimoto, 2000) . Our proposal on the construction mechanism of surface myoelectric signals could not be adapted to the electrical signals from m.biceps brachii. The present results suggest the different in architecture of muscle fibers and the innervation of the motor nerve in a motor unit between two muscles.
