From the biceps brachii of seven healthy subjects the muscular sound (SMG), detected by a microphonic transducer, and the surface EMG have been measured at 60% and 80% of the maximum voluntary contraction (MVC) during isometric conditions up to exhaustion. The power spectrum has been estimated by means of both the fast Fourier transform (FFT) and the maximum entropy spectral estimation (MESE), algorithm. From the spectrum the mean frequency has been computed. It appears that with time of exercise: 1) EMG shows the expected shift towards the lower frequencies (mean frequency from 50-70 Hz at the beginning of exercise to 25-45 Hz at exhaustion), independent of exercise intensity; 2) SMG shows the same trend only at 80% MVC. In some cases both at 60% and at 80% MVC the SMG power spectrum show a bimodal pattern.
|Title of host publication||IEEE/Engineering in Medicine and Biology Society Annual Conference|
|Number of pages||3|
|Publication status||Published - 1986|
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