Fatigue Related Changes in Electromyographic Coherence between Homologous Vastus Lateralis Muscles

Background. The aim of this study was to examine changes in the coherence between EMG signals of homologous quadriceps (vastus lateralis, VL) muscles during in the beginning and the end of multiple sustained isometric bilateral contraction at maximal effort. Methods. Twelve young healthy males participated in the study. The increase in coherence between EMG signals of homologous VL muscles in alpha band, beta band and gamma band was observed during the performance of sustained maximal bilateral isometric contraction with simultaneous decreases in bilateral force, CAR. EMG frequency and EMG amplitude. Results. The increase in beta band coherence during sustained maximal isometric contraction was negatively correlated with the decrease in bilateral force, CAR, EMG amplitude and EMG frequency indicating the possible role of beta coherence to improve VL muscle activation efficiency during maximal bilateral isometric contraction and overcome the effects of VL muscle fatigue in young healthy males. Keywords : muscle fatigue, EMG coherence, bilateral contraction, common drive.