Knee extensor performance of dominant and non-dominant limb throughout repeated isokinetic contractions, with special reference to peak torque and mean frequency of the EMG



Summary. The aim of this study was to investigate whether significant differences in peak torque (PT), mean power frequency of EMG (fmean) and perceived fatigue exist between the dominant and non-dominant knee extensors throughout repeated contractions. The present study forms part of a research project aimed at developing tests for the determination of the degree of motor control in patients with sequelae after CNS injury. A total of 22 clinically healthy subjects (14 males and eight females) took part in the investigation. The subjects performed endurance tests of the lower limbs, consisting of 100 repeated knee extensions using a Cybex dynamometer at 1.57 rad s-1. The patterns of PT, fmean and perception of fatigue throughout the endurance test were investigated. The endurance curves of PT and fmean showed, in common with other studies, an initial steep decrease followed by a stable phase. No significant differences existed between dominant and non-dominant knee extensors with regard to PT, fmean or perception of fatigue. The results indicate that it may be possible to use the contralateral knee extensors as an indicator of motor recovery in hemiplegia in patients with a high degree of recovery.