Study on surface electromyography characteristics of erector spinae muscles at different spinal anteversion angles of the scrapers / 中华劳动卫生职业病杂志

ABSTRACT

Objective: To simulate and evaluate the scraping and grinding work of workers with different spinal anteversion angles, and to explore the effects of different anteversion angles on the erector spinae muscles of scrapers. Methods: In November 2019, 16 male college student volunteers were recruited to simulate workers' scraping and grinding work. The parameters were 25°, 15 times/min, 15°, 30 times/min, 5°, 60 times/min respectively. The surface electromyography (sEMG) was used to collect the electromyographic signals of the erector spinae muscles, and the surface electromyographic characteristics of the erector spinae muscles were evaluated with Borg Scale. Results: There were significant differences between the maximum voluntary contraction percentage (MVE%) of the left and right erector spinae muscles groups in the three groups with different spinal anteversion angles (F(left)=13.41, P(left)<0.001; F(right)=4.74, P(right)=0.005) , and the EMG amplitude was higher at 25°, 15 times/min. At 15°, 30 times/min, MVE% of the left side was significantly higher than that of the right side (t=2.58, P=0.021) . There was significant difference in the mean power frequency (MPF) of the right erector spinae muscle in the three groups (F=9.42, P<0.001) , but there was no significant difference in the MPF of the left erector spinae muscle (F=0.30, P=0.823) . The fitting line showed that the left erector spinae muscle showed a downward trend at 5°, 60 times/min (t=-5.39, P=0.012) . Conclusion: Scrapers are less likely to be fatigued when the posture is 15°, 30 times/min, but they are more likely to be fatigued when working at 5°, 60 times/min.