Surface EMG evaluation of quadriceps femoris muscle in hemiplegic patients.

The method applied consists of evaluating the power spectra of the electromyographic (EMG) surface signal obtained during maximal isometric effort of the quadriceps femoris muscle. In hemiplegic patients it is possible to observe a particular frequency distribution towards the lowest values of the range considered. This trend might be accounted for by the morphological and enzyme- histochemical studies on the quadriceps femoris showing a selective atrophy of type 2 fibers. During rehabilitation treatment, however, it is imperative to consider parameters such as muscle strength changes and frequency values preferentially activated during the isometric effort (time-course). Observation of the pattern of the power spectra time-course therefore seems to contribute to a better view of the rehabilitation strategies suitable for exploiting the residual motor abilities.