The insulating stick method is the primary mode of operation for power supply in distribution networks. Operators often experience physical strain, including hand and shoulder joint pain, lumbar and cervical spine pain, and muscle strain. These symptoms can lead to chronic occupational injuries, such as musculoskeletal injuries (MSDs), with prolonged operation. It is important to address these issues to ensure the safety and well-being of operators. To evaluate the risk of MSDs, a study was conducted on insulated stick-method power-carrying operators. The study assessed upper limb muscle fatigue using surface electromyographic signals (sEMG). Eleven operating scenarios were selected, the biceps and triceps brachii were identified as the target muscles by human anatomy, and the sEMG signals were collected. The VMD signal noise reduction method was applied, and the noise reduced is EMG signals were used to extract the time and frequency domain features as parameters, and the perceptual assessment model based on sEMG and CR10 was constructed to assess fatigue in different operating modes.