Quantifying Differences in Muscular Exertion Levels during Simulated Carpentry Tasks

摘要

Work related musculoskeletal disorders (WMSDs) of the upper extremity in the construction industry have extremely high incidence rates. Construction workers are generally under higher physical demands due to the nature of their work tasks. Individual differences exist in performance of work tasks that may be responsible for injuries. Research has shown that these differences generally decrease with training. Therefore, in this study 6 experts and 6 novices performed 2 work tasks (deck building and picket insertion) to analyze muscle use differences across experience levels and work tasks. Surface EMG readings of 4 forearm muscles (Brachioradialis, ECU, FCU and FCR) were recorded. Percent of maximum (%MVC) for each muscle and task were calculated for all participants. Exertion levels were divided into 5 categories ranging from less than 15% to greater than 80% MVC and the frequency of time spent at each exertion level was recorded. Results indicate that differences between novices and experts existed in the amount of time spent under different exertion levels, though for both experience levels muscle activity was generally low. A difference in muscle recruitment pattern was also observed across tasks.