This article introduces the utility of electromyography (EMG) and mechanomyography (MMG) for the assessment of neuromuscular function, and discusses the interpretation of the EMG and MMG signals for various exercise perturbations. The results of these studies suggest that the use of EMG and MMG to determine muscle fatigue is robust. Future studies with clinical populations are needed, however, to determine the optimal use of EMG and/or MMG for assessing muscle function in rehabilitative settings.