This study aims to compare six observational methods for assessing arm- and hand-intensive tasks, based on literature review. The comparison was conducted in viewpoints of body regions, force/external load, motion repetition, other factors including static posture, coupling, duration/break, pace, temperature, precision task, and final risk or exposure level. The number of risk factors assessed was more, and assessment procedure was more complex than the observational methods for assessing whole-body postural loads such as Ovako Working Posture Analysis System(OWAS), Rapid Upper Limb Assessment(RULA), and Rapid Entire Body Assessment(REBA). Due to these, the intra- and inter-reliabilities were not high. A past study showed that while Hand Arm Risk Assessment Method(HARM) identified the smallest proportion of the work tasks as high risk, Strain Index(SI) and Quick Exposure Check(QEC) hand/wrist were the most rigorous with classifying most work tasks as high risk. This study showed that depending on the observational technique compared, the evaluation factors, risk or exposure level, and evaluation results were different, making it necessary to select a technique appropriate for the characteristics of the work being assessed.

This study aims to review observational methods for assessing postural loads such as OWAS, RULA and REBA, and to compare them, based on the literature survey. The literature was searched through academic database of ScienceDirect using the key words of observational methods, OWAS, RULA and REBA. The results exhibited that of the thee methods, RULA was cited in the literature and applied to manufacturing industries the most frequently. Although it has been known that RULA is appropriate for assessing upper body postures, it has been applied to healthcare and social work activities, agriculture, forestry, fishing, construction, mining and quarrying, which require unstable lower limb postures. The countries where more number of relevant studies have been carried out were USA, India, Brazil, UK, etc. It was recommended that of the three techniques, RULA may be better for assessing postural loads, because it evaluated postural loads more highly, irrespective of industry, work type and lower limb postures, and its assessment results had higher agreement rate with experts’ assessments than those of OWAS and REBA. It is expected that the results of this study will be used as a guideline for selecting an appropriate observational method.