APDF를 활용한 작업 부담 수준 별 작업자의 승모근에 대한 근육 부담 평가도구 개발

초록

Objective: The aim of this study is to develop and validate an evaluation tool that can evaluate trapezius muscle workloads to prevent musculoskeletal disorders (MSDs) in workers. Background: The number of musculoskeletal disorders among workers in industrial sites is increasing every year, and it is necessary to develop an assessment tool for evaluating muscle workloads to reduce MSDs. Method: Ten adult men who had no musculoskeletal disorders were recruited and performed drilling tasks for six working heights. The EMG was attached to the upper trapezius (UT), and the EMG data was used to extract 50%- and 90%-iles values for the six working heights to derive the amplitude probability distribution function (APDF) ranges, then, an assessment tool was developed to evaluate muscle loads using the APDF ranges. To validate the evaluation tool, it was applied to industrial sites in two ways; (1) Comparison of muscle loads by difficulty level, (2) Comparison of muscle loads in different ways of working with the same difficulty level. Results: An evaluation tool has been developed to evaluate muscle loads at four workload levels (low-, medium-, high-, and very high-risk levels) of APDF-50 and APDF-90, respectively. The final muscle loads were divided into four levels: Level 1- 'good', Level 2- 'normal', Level 3- 'caution', and Level 4- 'risk'. The results of the validation study showed that when evaluating the muscle loads for different levels of difficulties, the muscle load score of the overhead working height task was higher than that of the chest height task. In addition, when evaluating different work methods with the same difficulty levels, the muscle load score without the exoskeleton task was higher than that of with exoskeleton task. Conclusion: An assessment tool for evaluating muscle loads with a range of APDF- 50 and 90 by workload levels was developed and validated based on the different levels of working difficulty as well as the working method in this study. Application: The results of this study are expected to understand and prevent musculoskeletal disorders by enabling a comparative evaluation of workers' muscle load by workload level.

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