Analysis of electromyography records during voluntary contraction and the identification of specific characteristics of muscular activity

The electromyography (EMG) signals give information about different features of muscle function. A vast body of literature is devoted to the description and analysis of the muscular system abnormalities, the appearance of the fatigue and some factors who influence the muscular force, etc., recording EMG signals, which are very usefully in medical diagnosis and not only. This study is concerned with EMG measurements for some muscles of the superior arms, estimated by the muscular contraction force, for different percepts of maxim voluntary contraction (MVC). Acquisition is performed with the MP150 BIOPAC system, which is used in experiments concerning physiological signals and their numerical processing, with applications in diagnosis. Two experimental protocols are applied. The first consists of three sets of 100%, 80%, 50% of MVC (for five seconds each, with a break of two minutes). Next, sets of 65% of MVC for ten-fifteen seconds. The muscle evolution will be monitored until the appearance of fatigue by several statistical quantities, such as mean frequency (MF), median frequency, total power (TP) and root mean square (RMS). The main objectives of the work presented in the paper are EMG signal acquisition and statistical data processing.