Assessment of Muscle Fatigue Based on Electromyography in Electronic Assembly Industrial Workers

Abstract

This cross-sectional descriptive study aimed to measure muscle fatigue using electromyography (EMG) among 46 winding process workers who winding without using the machine (manual handling) and winding using the machine in the electronic assembly industry. Data were collected by using an EMG, type surface electromyography in 2 parameters: Maximum Voluntary Contraction (MVC) and muscle fatigue (MF/Time slope). The results of the EMG measurement of the muscles in the upper back and lower back using the Maximum Voluntary Contraction (MVC) parameter. The %MVC value in winding using the machine workers in a sitting position (Upper back: left = 26.44 right = 26.32, lower back: left = 22.75 right = 22.11) was lower than in winding without using the machine workers in a standing position (Upper back: left = 32.92 right = 32.39, lower back: left = 33.64 right = 31.76). From the EMG measurement in the upper back, lower back, and shoulder by using the median frequency (MF/time slope) parameter, throughout 8 working hours, the average fatigue divided into morning and afternoon work periods, muscle fatigue values on both the left and right sides of the body winding without using the machine workers in a standing position (MF/time slope in morning: Upper back: left =-0.67 right =-1.22, lower back: left =-0.51 right =-0.61, shoulder: left =-0.23 right =-1.47, in afternoon: Upper back: left =-0.65 right =-0.81, lower back: left =-0.50 right =-0.83 shoulder: left =-0.84 right =-1.46) and winding using the machine workers in a sitting position (MF/time slope in morning: Upper back: left =0.49  right =0.42, lower back: left =0.16 right =0.16, shoulder: left =-0.06 right =-0.83,  in afternoon: Upper back: left =-0.45 right =-0.84  lower back: left =-2.01 right =-2.05  shoulder: left =-0.72 right =-1.43), found that their fatigue values increased gradually over the duration of their work  This study found that workers experienced muscle fatigue which may be due to the fact that standing work involves more exertion, and while the worker sits, the muscles are stimulated to contract for a longer period of time. Therefore, health monitoring plans for musculoskeletal disorders (MSDs) should include physical exercise programs before, during, and after work in order to further promote muscle strength and endurance in workers.