Surface myoelectric signal analysis has proved effective for assessing the electrical manifestations of localized muscle fatigue. In the past, the analysis of muscle fatigue was restricted to isometric, constant force contractions due to the limitation of signal processing technique. The development and recent availability of spectral estimation techniques specifically designed for nonstationary signal analysis have made it possible to extend the employment of muscle fatigue assessment to dynamic contractions, thus opening new application fields such as ergonomics rehabilitation and sports medicine. This paper reviews the current study achievements of using surface myoelectric signals in muscle fatigue assessment, particularly in that during dynamic contractions. The conclusions provide theoretical bases for encouraging further studies on the mechanisms of muscle fatigue.