Electromyographic and phonomyographic patterns in muscle atrophy in man

Abstract

Since the report by Buchthal and Clemmesen (1941) on the electromyographical (EMG) changes caused by disuse atrophy, the only article published on this subject has been that by Wolf, Magora, and Gonen (1972). The most important feature described in this article was a reduction of frequency and amplitude of EMG waves during maximal voluntary effort. Furthermore, the interference pattern is not as markedly modified as in other diseases affecting the neuromuscular apparatus. Therefore, EMG generally is not employed in orthopedics and rehabilitation practice in cases of disuse atrophy. In past years; we have adopted the Fourier frequency analysis to obtain a better characterization of the EMG patterns during maximal effort in athletes and have gained some useful information on the effects of training (Cerquiglini et al., 1973). Thus, it seemed appropriate to apply the same technique to the study of changes in EM produced by disuse atrophy. Moreover, in our previous work, phonomyography (PMG) was utilized with EMG. This method reveals by means of suitable microphone the microvibration produced by muscles during contractions. These vibrations can be considered as a mechanical counterpart to the bioelectrical signal (Gordon and Holbourn, 1948); and, in our experience, PMG reveals mechanical activity in muscle just as well as EMG reveals the excitatory process.