Muscle extremely low frequency magnetic stimulation eliminates the effect of fatigue on EEG-EMG coherence during the lateral raise task: a pilot quantitative investigation

The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue and extremely low frequency (ELF) magnetic stimulation on electroencephalography (EEG)-electromyography (EMG) coherence during right arm lateral raise task. Eighteen healthy male subjects were recruited. EEG and EMG signals were simultaneously recorded from each subject while three different loads (0, 1 and 3kg) were added on the forearm. ELF magnetic stimulation was applied to the subject’s deltoid muscle between tasks during the resting period. Univariate ANOVA showed that all EEG-EMG coherence areas of C3, C4, CP5 and CP6 were not significantly affected by the force load (all p>0.05), and that muscle fatigue led to statistically significant reductions on the coherence area of gamma band in C3 (p=0.014) and CP5 (p=0.019). More interestingly, these statistically significant reductions disappeared with the application of muscle ELF magnetic stimulation, indicating its potential application to eliminate the effect of fatigue