Monitoring muscle fatigue is a hot research topic in rehabilitation medicine and sports science. However, the previous research on monitoring muscle fatigue is limited by the size and price of equipment and is not applicable to the field of sports. In this study, a wearable smart band powered by a resistive fabric strain sensor was implemented to measure thickness changes and combined with a portable electromyography(EMG) sensor to monitor bicep fatigue. A dumbbell curl training scheme was designed, and based on muscle physiology, fatigue-related features of the muscle thickness were proposed. The Pearson correlation coefficient between the median frequency (MDF) of EMG and the MDF of resistance was 0. 781 5, the Pearson correlation coefficient between the zero crossing rate (ZCR) of EMG and the enclosed area of the resistance was 0. 874 7, and the significant level P-values were 0. 022 0 and 0. 004 5, respectively. The results indicated that the muscle thickness characteristic indices were significantly correlated with common EMG fatigue indices. This study proves the feasibility of muscle fatigue monitoring based on muscle thickness characteristic indices and flexible fabric strain sensors as a supplementary method in the study of muscle fatigue. The methodology of this study has broad development prospects in the field of muscle fatigue research.