Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal

BackgroundWhen live working line operators engage in upper limb operations, working for a long time with raising arms and the exposure to adverse ergonomic factors tend to increase muscle load, cause fatigue accumulation, and increase the risk of work-related musculoskeletal disorders (WMSDs). Objec...

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Main Authors: Ruijian PAN, Xin LU, Conghan LIU, Chu CHEN, Lei LIU, Min LI
Format: Article
Language:English
Published: Editorial Committee of Journal of Environmental and Occupational Medicine 2025-03-01
Series:环境与职业医学
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Online Access:http://www.jeom.org/article/cn/10.11836/JEOM24384
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author Ruijian PAN
Xin LU
Conghan LIU
Chu CHEN
Lei LIU
Min LI
author_facet Ruijian PAN
Xin LU
Conghan LIU
Chu CHEN
Lei LIU
Min LI
author_sort Ruijian PAN
collection DOAJ
description BackgroundWhen live working line operators engage in upper limb operations, working for a long time with raising arms and the exposure to adverse ergonomic factors tend to increase muscle load, cause fatigue accumulation, and increase the risk of work-related musculoskeletal disorders (WMSDs). ObjectiveTo analyze work posture and associated muscle fatigue during executing breaking/connecting contact terminal, and identify adverse ergonomic factors of the work process. MethodsThis study recruited 10 volunteers to perform breaking/connecting contact terminal simulation. At a distance of 4.5, 3.5, and 2.5 m from the body to the wire, each performed the task 5 times. Visual 3D was used to analyze the kinematic data from motion capture. The surface electromyography (sEMG) signals of the deltoid, biceps, triceps, and brachioradialis were recorded during the simulation and analyzed for muscle fatigue using root mean square (RMS), median frequency (MF), and jointed EMG amplitude and spectrum analysis (JASA). After completion of each task, Borg scale was used to query the volunteers of their subjective fatigue. A 2-min rest was required between each distance. ResultsThe kinematic data from motion capture showed that in the entire process of the task, the right upper limb was higher when lifting, with the right shoulder joint maintaining flexion and fluctuating periodically between abduction and adduction, external and internal rotation, the right elbow joint maintaining flexion and supination. The frequency of task cycle showed a significant effect on the Borg scale scores (P<0.001, partial \begin{document}$ {\eta }^{2} $\end{document}=0.464); the distance showed no significant effect on the Borg scale scores (P>0.05, partial \begin{document}$ {\eta }^{2} $\end{document}=0.002); their interaction effect was not significant (P>0.05, partial \begin{document}$ {\eta }^{2} $\end{document}=0.020). The results of the sEMG signals showed that at a distance of 4.5 m, the volunteers had the highest percentages of maximal voluntary electrical activation (MVE%) in the deltoid and right brachioradialis and the lowest MF values in the deltoid and left brachioradialis after completing 5 task cycles. The results of JASA showed that fatigue was observed in brachioradialis and deltoid after completing 5 task cycles at a distance of 4.5 m, the right deltoid and right brachioradialis at a distance of 3.5 m, in the brachioradialis, deltoid, and left bicep at a distance of 2.5 m. ConclusionThe subjective fatigue of workers who engaged in breaking/connecting contact terminal elevates with more repetitive operations. Based on the sEMG and motion capture analysis, it can be found that improper distance between the workers and the target work area can increase the burden from poor posture and improper use of work equipment, and lead to muscle fatigue; the deltoid and brachioradialis are the key muscles of fatigue in this type of operation; changing the angle of the elbow joint and the shoulder joint during the process of the operation can affect the deltoid and brachioradialis exertion and loading.
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spelling doaj-art-7e2c2f54bca548738437bf0974ab8a2a2025-08-20T03:17:43ZengEditorial Committee of Journal of Environmental and Occupational Medicine环境与职业医学2095-99822025-03-0142326026910.11836/JEOM2438424384Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminalRuijian PAN0Xin LU1Conghan LIU2Chu CHEN3Lei LIU4Min LI5Institute of High Voltage Technology, Electric Power Research Institute of China Southern Power Grid, Guangdong, Guangzhou 510663, ChinaMachine Inspection and Non Power Outage Operation Center, Guangxi Power Grid Corporation, Guangxi, Nanning 520023, ChinaMachine Inspection and Non Power Outage Operation Center, Guangxi Power Grid Corporation, Guangxi, Nanning 520023, ChinaMachine Inspection and Non Power Outage Operation Center, Guangxi Power Grid Corporation, Guangxi, Nanning 520023, ChinaInstitute of High Voltage Technology, Electric Power Research Institute of China Southern Power Grid, Guangdong, Guangzhou 510663, ChinaInstitute of High Voltage Technology, Electric Power Research Institute of China Southern Power Grid, Guangdong, Guangzhou 510663, ChinaBackgroundWhen live working line operators engage in upper limb operations, working for a long time with raising arms and the exposure to adverse ergonomic factors tend to increase muscle load, cause fatigue accumulation, and increase the risk of work-related musculoskeletal disorders (WMSDs). ObjectiveTo analyze work posture and associated muscle fatigue during executing breaking/connecting contact terminal, and identify adverse ergonomic factors of the work process. MethodsThis study recruited 10 volunteers to perform breaking/connecting contact terminal simulation. At a distance of 4.5, 3.5, and 2.5 m from the body to the wire, each performed the task 5 times. Visual 3D was used to analyze the kinematic data from motion capture. The surface electromyography (sEMG) signals of the deltoid, biceps, triceps, and brachioradialis were recorded during the simulation and analyzed for muscle fatigue using root mean square (RMS), median frequency (MF), and jointed EMG amplitude and spectrum analysis (JASA). After completion of each task, Borg scale was used to query the volunteers of their subjective fatigue. A 2-min rest was required between each distance. ResultsThe kinematic data from motion capture showed that in the entire process of the task, the right upper limb was higher when lifting, with the right shoulder joint maintaining flexion and fluctuating periodically between abduction and adduction, external and internal rotation, the right elbow joint maintaining flexion and supination. The frequency of task cycle showed a significant effect on the Borg scale scores (P<0.001, partial \begin{document}$ {\eta }^{2} $\end{document}=0.464); the distance showed no significant effect on the Borg scale scores (P>0.05, partial \begin{document}$ {\eta }^{2} $\end{document}=0.002); their interaction effect was not significant (P>0.05, partial \begin{document}$ {\eta }^{2} $\end{document}=0.020). The results of the sEMG signals showed that at a distance of 4.5 m, the volunteers had the highest percentages of maximal voluntary electrical activation (MVE%) in the deltoid and right brachioradialis and the lowest MF values in the deltoid and left brachioradialis after completing 5 task cycles. The results of JASA showed that fatigue was observed in brachioradialis and deltoid after completing 5 task cycles at a distance of 4.5 m, the right deltoid and right brachioradialis at a distance of 3.5 m, in the brachioradialis, deltoid, and left bicep at a distance of 2.5 m. ConclusionThe subjective fatigue of workers who engaged in breaking/connecting contact terminal elevates with more repetitive operations. Based on the sEMG and motion capture analysis, it can be found that improper distance between the workers and the target work area can increase the burden from poor posture and improper use of work equipment, and lead to muscle fatigue; the deltoid and brachioradialis are the key muscles of fatigue in this type of operation; changing the angle of the elbow joint and the shoulder joint during the process of the operation can affect the deltoid and brachioradialis exertion and loading.http://www.jeom.org/article/cn/10.11836/JEOM24384surface electromyographylive workingergonomicmotion capturemuscle fatiguework posture
spellingShingle Ruijian PAN
Xin LU
Conghan LIU
Chu CHEN
Lei LIU
Min LI
Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
环境与职业医学
surface electromyography
live working
ergonomic
motion capture
muscle fatigue
work posture
title Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
title_full Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
title_fullStr Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
title_full_unstemmed Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
title_short Simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
title_sort simulation analysis of work posture and muscle fatigue in breaking and connecting contact terminal
topic surface electromyography
live working
ergonomic
motion capture
muscle fatigue
work posture
url http://www.jeom.org/article/cn/10.11836/JEOM24384
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AT chuchen simulationanalysisofworkpostureandmusclefatigueinbreakingandconnectingcontactterminal
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