ORIGINAL ARTICLES   Free access

Europa Medicophysica 1998 March;34(1):11-6

Copyright © 1998 EDIZIONI MINERVA MEDICA

language: English

The relationship between isokinetic endurance and surface electromyographic signals

Felicetti G. ¹, Maestri R. ², Rovescala R. ¹, Monzani M. ³

¹ “Salvatore Maugeri” Foundation, IRCCS Rehabilitation Center of Montescano, Rehabilitation Division; ² Bioengineering Unit; ³ Elektron Milan, Italy

In this paper, we studied the relationship between isokinetic endurance during flexion-extensions of the knee and surface EMG. The EMG power spectrum of the vastus medialis, vastus lateralis, semitendinosus and biceps femuris during isokinetic contraction was analysed. We evaluated 20 male subjects (mean age 25.3 years). None participated in competitive sports or was affected by orthopaedic pathologies. During the endurance test, each patient performed 30 isokinetic flexion-extensions of the knee at 180 degrees/second. Surface EMG signals, isokinetic torque and angular values were monitored simultaneously. The torque signal was filtered with a medium filter and the peak values of the 30 repetitions were calculated. The decrease (%) in these parameters at the end of the investigation was calculated. We identified intervals of steady EMG activity for each EMG signal recorded from each of the 4 muscles; the mean frequency of the power spectrum and the decrease (%) in peak torque at the end of the endurance test were then computed. Our results did not show any significant correlation between the decay of the median frequency; whereas there was a correlation between the decay of the median frequency in both knee flexors and extensors. The decay (%) of the vastus medialis and biceps femuris was compared with the decays of the vastus lateralis and the semitendinosus.