Abstract
An electronic e.m.g. analyser is described which can continuously analyse the r.m.s. amplitude and the frequency components of the e.m.g. over the frequency range of 35 to 350 Hz. The analyser uses 10 active bandpass filters to measure some of the frquency components of the e.m.g. The amplitude of the frequency components of the e.m.g. are then processed by an analogue computer to calculate their median frequency. An r.m.s. converter is used to calculate the r.m.s. amplitude of the e.m.g. The degree of fatigue induced in the muscle is then quantified from the downward shift of the centre frequency of the e.m.g. Four subjects were asked to exert brief contractions at tensions up to 100% of their maximum strength and fatiguing isometric contraction at tensions of 25, 40 and 70% of their maximum strength to test the operation of the analyser. As a basis for comparison, the e.m.g. recorded during these contractions was also processed through Fourier analysis on a digital computer. The results of these experiments shows a striking similarity of the results between the two techniques.
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Petrofsky, J.S. Filter bank analyser for automatic analysis of the e.m.g.. Med. Biol. Eng. Comput. 18, 585–590 (1980). https://doi.org/10.1007/BF02443130
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DOI: https://doi.org/10.1007/BF02443130