Comparison Between Direct Measurement and Observation Methods for Upper eztremity Activity Assessment at Workplace
To evaluate the risk factors for upper extremity musculoskeletal disorders, the direct measurement has the advantage of better validity while the observation method and self-report have the strength of convenience in operation. The aim of this study are to evaluate the correlation of exposure variables monitored by direct measurement and observation method, and to find out the most feasible and valid parameters by observation method to assess hand activity at the work place. A total of 35 different tasks by 19 subjects of 10 companies were included in this study, which were primarily involved with upper extremity activity. All subjects filled in a modified Nordic Musculoskeletal Questionnaire to report their health outcome prior to the beginning of this study. Then, the study subjects were asked to work as usual for the designated task for 15 minutes or more than 5 cycles per task. Meanwhile, direct measurements, including surface electromyography and biaxial electrogoniometers for wrist, were applied to record the bioelectronic signals for hand activity. All the subjects hand activities were video taped and, later, rated by a reviewer according to the Strain Index (SI) checklist and hand activity level (HAL) checklist by the American Conference of Governmental Industrial Hygienists. Both direct measurement and observation method provided exposure variables for exertion force and frequency. Results showed that the prevalence of discomforts in wrist was higher than other upper extremity parts among the study subject. The parameters of exertion frequency by direct measurement and video observation were significantly correlated (r=0.62, p<0.01). The efforts per minute estimated by SI checklist was correlated with the mean power frequency of exertion (r=0.66, p<0.001) and the root mean square of wrist deviation speed by the biaxial electrogoniometers (r=0.51, p<0.01). However, such agreement was not found for exposure variable of exertion force. The finding of the present study suggested that the frequency of upper extremity motion estimated by observation method could be used as a feasible indicator for exposure loading assessment at workplace if direct measurement is not suitable for all study subjects.
musculoskeletal disorder ezposure assessment observation
Yen-Ting Chen Yaw-Huei Hwang
Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan
国际会议
17th World Congress on Ergonomics(第十七届国际人类工效学大会)
北京
英文
1-10
2009-08-09（万方平台首次上网日期，不代表论文的发表时间）