The comparison was based on a literature review without time limitations and was conducted on various factors related to observational methods. This study aimed to systematically compare three representative observational methods for assessing musculoskeletal loadings and their association with musculoskeletal disorders (MSDs): Ovako Working Posture Analysis System (OWAS), Rapid Upper Limb Assessment (RULA), and Rapid Entire Body Assessment (REBA). So, there is a need to identify all the insensitive zones within a method that has a considerable difference in perceived exertion. It is observed that outcome of assessment methods is insensitive to some posture cases. Similarly, REBA and RULA may be better suited for the load range 5 kg − 10 kg and load greater than 10 kg respectively. It may be concluded from the study that OWAS may be better suited to evaluate risk if the load is less than 5 kg. ANOVA was carried out to identify significant factors. Phase three includes the result’s validation. In the second phase, 24 male participants were selected to simulate the selected set of 100 postures-load combination in the laboratory and their perceived exertion rating was noted. The first phase involves assessing 25 postures at four different load levels (100 postures) to confirm the existence of variation in outcome of assessment. The current research is carried out in three phases. The methods such as Ovako working posture analysing system (OWAS), Rapid entire body assessment (REBA) and Rapid upper limb assessment (RULA) were used for the evaluation. The paper highlights the need to determine applicability of various ergonomic assessment methods.
Based on these comparisons, it seems that the LEBA may be better than the RULA for estimating postural stress and predicting the association with MSDs. The results showed that compared to the RULA, the LEBA was better at evaluating various factors affecting postural loads and assessing musculoskeletal loadings, was better correlated with various postural load criteria, could predict the association with MSDs more accurately, and had higher inter- and intra-rater reliabilities. The two methods were compared in various categories, including general characteristics, risk levels, postural load criteria, association with MSDs, influencing factors, and inter- and intra-rater reliabilities based on relevant previous studies. This study aimed to compare the Rapid Upper Limb Assessment (RULA), a representative observational method, and the Loading on the Entire Body Assessment (LEBA), a newly developed tool for assessing postural loads and their association with MSDs. Various observational methods have been developed and applied in industrial settings with the aim of preventing musculoskeletal disorders (MSDs). With this paper, ergonomic practitioners can be made aware of insensitive and sensitive zones in posture assessment. This paper demonstrates the need for understanding of RULA method among the researchers. The justification of the RULA methodology available in the existing literature is very limited. Ordinal regression analysis was performed to identify the most influencing body variable and its weight in estimating the grand RULA score.
Posture scores were also noted involving sudden jumps. Combinations of posture where no change was observed and corresponding ranges were noted. One parameter was changed while keeping other parameters fixed to understand its effect on the output score.
Full factorial design was divided into parts using a forward approach to access the sensitivity. The sensitivity analysis of RULA along with the ordinal regression analysis offer deeper insights into the methodology used for the assessment of posture. The paper aims primarily to study the sensitivity of Rapid upper limb assessment (RULA) and identification of insensitive and sensitive posture zones.