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International Journal of Occupational Safety and Ergonomics ISSN: 1080-3548 (Print) 2376-9130 (Online) Journal homepage: https://www.tandfonline.com/loi/tose20 Comparisons of ergonomic evaluation tools (ALLA, RULA, REBA and OWAS) for farm work Yong-Ku Kong, Sung-yong Lee, Kyung-Suk Lee & Dae-Min Kim To cite this article: Yong-Ku Kong, Sung-yong Lee, Kyung-Suk Lee & Dae-Min Kim (2018) Comparisons of ergonomic evaluation tools (ALLA, RULA, REBA and OWAS) for farm work, International Journal of Occupational Safety and Ergonomics, 24:2, 218-223, DOI: 10.1080/10803548.2017.1306960 To link to this article: https://doi.org/10.1080/10803548.2017.1306960 Accepted author version posted online: 17 Mar 2017. Published online: 02 May 2017. Submit your article to this journal Article views: 955 View Crossmark data Citing articles: 3 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tose20 International Journal of Occupational Safety and Ergonomics (JOSE), 2018 Vol. 24, No. 2, 218–223, https://doi.org/10.1080/10803548.2017.1306960 Comparisons of ergonomic evaluation tools (ALLA, RULA, REBA and OWAS) for farm work Yong-Ku Konga , Sung-yong Leea , Kyung-Suk Leeb and Dae-Min Kimc∗ a Department of Industrial Engineering, Sungkyunkwan University, Republic of Korea; b Rural Resources Development Institute, NIAST, RDA, Republic of Korea; c Division of Mechatronics Engineering, Dongseo University, Republic of Korea Introduction. The purpose of this study was to validate the agricultural lower limb assessment (ALLA) ergonomic checklist, which was developed for various agricultural tasks in Korea. Methods. One hundred and ninety-six working postures were selected from the real agricultural tasks to verify ALLA, a lower limb body posture assessment tool, and then evaluated by 16 ergonomic experts. Hit rate, quadratic weighted κ, one-way analysis of variance and t-test analyses were applied to compare ALLA with other assessment tools. Results. ALLA analysis had a superior hit rate with ergonomic expert assessment compared with other assessment tools. Quadratic weighted κ analysis also showed that ALLA provided superior estimates of risk levels for farm working postures. Discussion. ALLA would be an appropriate assessment tool to estimate risk factors for various lower limb body postures which frequently occur in agricultural tasks in Korea. ALLA is a simple and accurate risk assessment tool that could be usefully applied to identify and mitigate risk factors and work-related musculoskeletal disorders in agricultural tasks, and also to evaluate the effects of control and intervention for working conditions. Keywords: ergonomic risk assessment tools; agricultural lower limb assessment; rapid entire body assessment; rapid upper limb assessment; Ovako working posture analysis system 1. Introduction Many studies have investigated work risks using ergonomic risk assessment tools to prevent musculoskeletal disorders. The most common assessment tools include rapid entire body assessment (REBA) [1], rapid upper limb assessment (RULA) [2], the Ovako working posture analysis system (OWAS) [3], posture, activity, tools and handling (PATH) [4] and occupational repetitive action (OCRA) [5]. However, these ergonomic assessment tools focus on the posture of the upper rather than lower limbs, and do not apply well to the agricultural, manufacturing or construction sectors. These tools are therefore unable to address the continued increase in skeletal disease in Korea, particularly in agricultural workers. Musculoskeletal disorders have steadily increased in Korea since 2003. The decrease in economically active farm workers, aging of farm workers and reduction of population per farmhouse has brought about increased cultivated acreage per farmhouse. Thus, with a decreasing labor force, significance increases in labor intensity have eventuated. Consequently, the incidence of musculoskeletal disorders for agricultural, forestry and fishery workers (61.5%) was 2.5 times that of other sector workers (25.1%) [6]. The many studies produce various results according to the specific country, race, and age. Even statistically significant results from one study may transfer to another *Corresponding author. Email: [email protected] © 2017 Central Institute for Labour Protection – National Research Institute (CIOP-PIB) from a different country, due to anthropometric and cultural differences. Kirby et al. [7] showed that lower limb postures affect the stability and mobility of the whole body, and, thus, affect the whole working posture load. Gallagher et al. [8] showed that maximum achievable lifting load is affected by lower limb posture. Kong et al. [9] developed the agricultural lower limb assessment (ALLA) tool, a diverse and segmented ergonomic lower limb assessment tool suitable for farm work for Koreans. ALLA is especially useful for lower limb burdening work, and is based on results acquired through human body physiological experiments targeting Koreans using lower limb postures not often observed in farm work. This study measured the electromyography (EMG) of muscles, heart rate and subjective discomfort to maintain each of 13 lower limb postures. The risk level on working posture, exposed time and considering both working posture and exposed time can be evaluated through four risk levels (1 = medium, 2 = moderate, 3 = high, 4 = very high). The 13 ALLA lower limb postures can be categorized into postures resulting from the change of knee angles, squatting and kneeling. Rick assessment for each posture can be performed by analyzing the risk inherent to the posture and the risk derived from retaining the posture (Figure 1). Kong et al. [9] proposed ALLA and validated International Journal of Occupational Safety and Ergonomics (JOSE) 219 Figure 1. Agricultural lower limb assessment (ALLA). Note: The full color version of this figure is available online. it through a comparative analysis with other evaluation tools. However, statistical significance was not explained, because no evaluation of various postures was conducted. This study aims to compare ALLA for farm work, targeting various lower limb postures, against other ergonomic assessment tools (OWAS, RULA and REBA) used for musculoskeletal factor surveys. 2. Methods 2.1. Posture selection This study selected 196 postures occurring in Korea’s agricultural tasks (farm work) to verify the validity of lower limb assessment tools, including ALLA, RULA, REBA and OWAS. An evaluation tool should be able to evaluate various postures precisely, irrelevant of high or low risk. Therefore, this study selected the working postures as follows. The risk of each crop was scored using a 100-point scale, based on the general health status and fatigue, disease rate per crop, labor intensity and hard body part per crop and on survey results on subjective symptoms of musculoskeletal disorders per crop from Kim [10]. This study then classified risks into four levels according to the score, and selected crops at different working heights – under knee (bottom–knee), near waist (knee– breast) and above shoulder – for each crop in each risk level. A total of 10 crops were selected, as presented in Table 1, because there is no crop corresponding to the near waist working height for the very high and medium risk levels. To identify the working postures for the 10 selected crops, researchers visited farms and took photographs or referred to farm work reports [11–18]. 2.2. Evaluation by ergonomic experts Sixteen ergonomic experts (10 ergonomists, 4 industrial medical experts and 2 agricultural experts) evaluated each crop’s working postures using a 10-point scale, where 1 = very safe posture and 10 = very risky posture, excluding factors such as weights or vibration on the given posture. According to the mean scores measured by the ergonomic experts for each posture, the risk was classified into four levels according to the mean scores: 1 = very low (1.00–3.25), 2 = low (3.25–5.50), 3 = high (5.50–7.25) and 4 = very high (7.25–10.00). This study considered the suitability of each evaluation tool by analyzing whether the tool-evaluated results were consistent with the expert assessment. 2.3. Evaluation of ergonomic assessment tools To evaluate each assessment tool, the risk level was estimated for lower limb postures following the ALLA system. However, risk levels cannot be estimated using only lower limb postures for RULA, REBA and OWAS. Therefore, for those systems, final risk levels were estimated using 220 Y.-K. Kong et al. Table 1. Characteristics of the selected 10 crops. Risk level Working height Very high Above the shoulder Near waist (knee–breast) Under knee (bottom–knee) Grape Table 2. κ <0.20 0.21–0.40 0.41–0.60 0.61–0.80 >0.80 Strawberry Criteria of κ analysis. Strength of agreement Poor Fair Moderate Good Very good the upper limb postures corresponding to the lower limb postures. ALLA, RULA and OWAS all use four action categories levels, whereas REBA uses five action levels. Therefore, to align the systems for the purposes of the current study, REBA action level 0 (no action undertaken) was amalgamated with action level 1. 2.4. Statistical analysis Hit rate, quadratic weighted κ, one-way analysis of variance (ANOVA) and one-way t-test analyses were used to examine consistency between expert assessment and ALLA, OWAS, REBA and RULA. First, hit rate analysis classifies expert assessment results by risk level, and then evaluates the postures corresponding to each risk level from each assessment tool, producing a rate of common outcomes or hit rate. For example, suppose the expert assessment produced 30 postures with risk level 1. Each assessment tool evaluates these 30 postures, producing various risk levels (1–4) which are divided by the total number of postures, namely 30, and then the rate is demonstrated. Second, quadratic weighted κ analysis was performed using the κ value calculated through the expert assessment results and the evaluation result of each assessment tool. The κ value was between 0 and 1, and the κ criteria are presented in Table 2. Third, one-way ANOVA was conducted to check the effects of the assessment tools (RULA, REBA, OWAS and ALLA) against the final risk level from expert evaluation, by group (risk level 1–4). To identify differences between the assessment tools, when significant differences were observed for a given final risk level, due to an assessment tool, the Tukey test was performed post analysis. High A little high Peach Rice Cucumber Tangerine Chrysanthemum Tomato Medium Pear Oriental melon Lastly, the one-way t test was performed to probe whether the assessment tools provided significantly different outcomes from expert assessment. 3. Results 3.1. Hit rate analysis Table 3 presents the hit rates for the various risk levels. The number of each working posture from 1 to 4 risk levels of expert assessment results on 196 postures was 12, 72, 96 and 14, respectively. The hit rate of expert assessment results and the ALLA evaluation results was 15.1% in the working postures with risk level 1 of the expert assessment results. The working postures with risk levels 2 and 3 were over 50%, namely 52.1 and 57.1%, respectively, and the working postures with risk level 4 showed 37.1% of hit rate. The hit rate of expert assessment and REBA assessment was 100% for working postures with expert assessed risk level 1. However, the risk level of all working postures was assessed as risk level 1 by REBA, irrelevant of the expert assessment. The hit rate of expert assessment and RULA assessment was 100% for working postures with expert assessed risk level 1, but only 12.3% for working postures with assessed risk level 2, and postures with risk levels 3 and 4 were RULA assessed as risk levels 1 and 2, respectively. The hit rate of expert assessment and OWAS assessment was similar to that for RULA. The hit rate for working postures with expert assessed risk level 1 was 98.1%, with 28.8% for risk level 2 postures. Working postures with expert assessed risk levels 3 and 4 were OWAS assessed with risk level 1 and risk level 2, respectively. 3.2. Quadratic weighted κ analysis Quadratic weighted κ analysis was used to examine the hit rate between expert assessment and the assessment tools, as presented in Table 4. The κ value for expert assessment and ALLA assessment was 0.803, which shows good consistency. κ for expert assessment and RULA assessment was 0.627, which shows relatively small consistency, whereas for REBA and OWAS the κ value was 0.490 and 0.501, respectively, showing only moderate consistency. International Journal of Occupational Safety and Ergonomics (JOSE) 221 Table 3. Results of hit rates (%) for all ergonomic risk evaluation tools for the expert assessments ALLA Risk level Expert assessment 1 2 3 4 12 72 98 14 1 2 15.1 35.7 20.0 84.9 52.1 REBA 3 4 1 20.5 57.1 62.9 2.7 22.9 37.1 100 100 100 100 2 3 RULA 4 1 2 100 87.7 57.1 80.0 12.3 42.9 20.0 OWAS 3 4 1 2 98.1 71.2 60.0 11.4 1.9 28.8 40.0 88.6 3 4 Note: ALLA = agricultural lower limb assessment; OWAS = Ovako working posture analysis system; REBA = rapid entire body assessment; RULA = rapid upper limb assessment. Shading represents accuracy (%) of expert assessment results and each assessment’s results. Number represents hit rate, no number means 0 hit rate. For example, 12 postures were evaluated as a ‘risk level 1’ by experts’ evaluation and then these were evaluated as ‘risk level 1’ – 15.1% or ‘risk level 2’ – 84.9% by ALLA in this study. Table 4. Results of quadratic weighted κ analysis for all ergonomic risk evaluation tools. Checklist κ Strength of agreement ALLA REBA RULA OWAS 0.803 0.490 0.627 0.501 Very good Moderate Good Moderate Note: ALLA = agricultural lower limb assessment; OWAS = Ovako working posture analysis system; REBA = rapid entire body assessment; RULA = rapid upper limb assessment. 3.3. One-way ANOVA and t-test analysis All assessment tools were significantly different from expert assessment for all expert assessment groups (α = 0.05). Figure 2 shows each assessment tool’s evaluation by the expert assessment group. ALLA showed the highest assessed risk for all expert groups, with REBA always showing the lowest. For the expert assessed risk level 1 group, ALLA was significantly higher at 1.9, whereas REBA and RULA were the lowest assessed risk (1.0) and not significant different from the expert assessment. For the expert assessed risk level 2 group, ALLA was again the highest assessment at 2.1, with no significant difference from the expert assessment. OWAS, RULA and REBA mean assessment was 1.3, 1.1 and 1.0, respectively, all of which are significantly different from expert assessment. The expert assessed risk level 3 group showed similar outcomes to the expert assessed risk level 2 group. ALLA assessment was the highest at 2.6, and was not significantly different from the expert assessment, whereas OWAS, RULA and REBA assessment was 1.5, 1.3 and 1.0, respectively, which were all significantly different from expert assessment. Finally, for the expert assessed risk level 4 group, mean ALLA, OWAS, RULA and REBA assessments (3.1, 1.7, 1.3 and 1.0, respectively) were all significantly different from expert assessment. In Figure 2 the assessments have also been grouped by letter (A, B, C, D), where the same letter indicates the groups are not significantly different. 4. Discussion This study aimed to verify ALLA, a lower limb posture assessment tool for agriculture, by comparing ALLA and existing widely used ergonomic assessment tools (OWAS, RULA and REBA) with direct expert assessment using identified working postures occurring in agricultural tasks. ALLA reflects the expert assessed risk level better than the other ergonomic assessment tools considered. The other assessment tools largely evaluated the risk level of most agricultural tasks as 1 or 2, regardless of the expert assessment. Hence they tended to produce a high hit rate for expert assessed risk level 1 or 2 groups, but poor hit rates for expert assessed risk level 2 or higher groups. This outcome is a result of lower limb posture assessment being largely underestimated in the OWAS, RULA and REBA systems, whereas ALLA was specifically developed to address this limitation [9]. Quadratic weighted κ analysis was used to examine consistency between each assessment tool and expert assessment. ALLA was quite consistent with expert assessment, and significantly superior to the other assessment tools. The one-way ANOVA also showed that ALLA had the highest assessed risk level across all expert assessed groups, whereas REBA had the lowest. Although REBA does include load assessment on lower limb postures, compared with RULA, REBA’s hit rate was the lowest because only four risk levels (1, 1, 2 or 3) were achieved upon evaluation of all postures, setting them as the basis except for lower limb postures. On the other hand, RULA provided only two risk levels (1 or 3). Therefore, REBA mean assessment was smaller than RULA, even though there was no significant difference. This study also analyzed differences between expert assessment and each assessment tool. For the expert 222 Y.-K. Kong et al. Figure 2. Results of one-way analysis of variance (ANOVA). Note: *significant difference in statistics; A, B, C, D = significant grouping in statistics; ALLA = agricultural lower limb assessment; OWAS = Ovako working posture analysis system; REBA = rapid entire body assessment; RULA = rapid upper limb assessment. The full color version of this figure is available online. assessed risk level 1 group, no significant differences were shown except for ALLA. For expert assessed risk levels 2 and 3 groups, only ALLA assessment showed no significant difference from expert assessment. Finally, for the expert assessed risk level 4 group, all assessment tools were significantly different from expert assessment, although ALLA was the closest outcome to expert assessment. Lee et al. [19] evaluated load change according to the height of a support and duration of the squatting posture using a psychophysical method. Lee et al. [19] assessed 31 lower limb loads using subjective discomfort, similar to ALLA. This study analyzed and selected lower limb postures frequently occurring in farming work in Korea, based on postures from the studies discussed that showed significant differences in subjective discomfort. Previous studies compared tasks using various assessment tools. Lee et al. [19] compared the most widely used three tools, OWAS, RULA and REBA, and analyzed the features from the work posture loads. They determined that waist postures played a pivotal role in deciding overall load level in OWAS, compared with shoulder postures. Because the current study evaluated various lower limb postures, and unified upper limb postures as basic postures, OWAS assessment risk levels 1 and 2 were mainly shown. Lee et al. [19] also reported differences in cognitive discomfort, because RULA did not discriminate lower limb postures sufficiently, which is similar to the current study that has shown consistency is low between expert assessment and RULA assessment for lower limb postures. Lee et al. [19] showed that REBA was more suitable for evaluating whole body working postures than other assessment tools. However, the current study shows that the consistency between REBA and expert assessment was relatively lower than the other assessment tools. This is because OWAS, RULA and REBA do not reflect various lower limb postures occurring in farming work. Lee et al. [20] reported that the OCRA assessment tool correlation with labor intensity in the automobile industry was higher than that of RULA, and suggested the reason for this was that OCRA’s evaluation ratio on repetitiveness, a characteristic of the car assembly process, was relatively higher. They argued that the use of a proper tool suitable for specific work characteristics was required. Similarly, the current study shows that ALLA, which focuses on lower limb postures frequently occurring in farming work, is more suitable than assessment tools that largely ignore lower limb posture. Lee et al. [21] analyzed specific body parts for specific work using OWAS, RULA, REBA and quick exposure check (QEC). They compared waist bending when working with weights and waist bending, squatting, neck extension and neck bending for assembly work, and acquired different results for each situation. They also concluded that an appropriate assessment tool should be used according to posture. Therefore, the current study recommends using ALLA, because this lower limb assessment tool has shown superior agreement with expert assessment of risk levels for lower limb postures. Because experts commonly use REBA, RULA and OWAS, these existing assessment tools become the standard for posture evaluation. Although existing assessment tools consider upper and lower limb postures, they cannot independently evaluate upper or lower limb postures. 5. Conclusion ALLA risk level assessments show high consistency with expert risk level assessment for farming work postures. International Journal of Occupational Safety and Ergonomics (JOSE) Therefore, ALLA is suitable for evaluation of lower limb postures for farming work. The current study shows that ALLA can conveniently and objectively evaluate work-related musculoskeletal disorder (WMSD) risk levels for lower limb postures commonly observed in farming work in Korea, such as squatting, going down on one’s knees and sitting on the floor. Therefore, ALLA can be used as an assessment tool to evaluate the effects of disease prevention, management and working environment improvement by objectively evaluating WMSD risk levels in agricultural tasks. Although ALLA is suitable for measuring risk level by body part, it is insufficient to evaluate whole body postures. Extending the current study, an upper limb assessment tool – agricultural upper limb assessment (AULA) [22] – has been developed, and combined with ALLA, providing a whole body assessment tool – agricultural whole body assessment (AWBA) [23]. The application of AWBA will be assessed through further verification studies. [9] [10] [11] [12] [13] [14] Disclosure statement No potential conflict of interest was reported by the authors. [15] Funding This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [NRF-2016R1A1A09 918189]. [16] [17] References [1] Hignett S, McAtamney L. Rapid entire body assessment (REBA). Appl Ergon. 2000;31:201–205. doi:10.1016/S00 03-6870(99)00039-3 [2] McAtamney L, Nigel Corlett E. RULA: a survey method for the investigation of work-related upper limb disorders. Appl Ergon. 1993;24(2):91–99. doi:10.1016/0003-6870(93)900 80-S [3] Karhu O, Kansi P, Kuorinka I. Correcting working postures in industry: a practical method for analysis. Appl Ergon. 1977;8(4):199–201. doi:10.1016/0003-6870(77)90164-8 [4] Buchholz B, Paquet V, Punnett L, et al. PATH: a work sampling-based approach to ergonomic job analysis for construction and other non-repetitive work. Appl Ergon. 1996;27(3):177–187. doi:10.1016/0003-6870(95)00078-X [5] Occhipinti E, Colombini D. [Proposal of a concise index for the evaluation of the exposure to repetitive movements of the upper extremity (OCRA index)]. Med Lav. 1996;87:526–548. Italian. [6] Rural Development Administration. [Comparison analysis of main disorder and health behavior of farmers]. Suwon: Farmers Health & Safety Information Center; 2004. Korean. [7] Kirby RL, Price NA, MacLeod DA. The influence of foot position on standing balance. J Biomech. 1987;20(4):423– 427. doi:10.1016/0021-9290(87)90049-2 [8] Gallagher S, Marras WS, Bobick TG. Lifting in stooped and kneeling postures: effects on lifting capacity, metabolic [18] [19] [20] [21] [22] [23] 223 costs, and electromyography of eight trunk muscles. Int J Ind Ergon. 1988;3:65–76. doi:10.1016/0169-8141(88)90 007-8 Kong Y-K, Han J-G, Kim D-M. [Development of an ergonomic checklist for the investigation of work-related lower limb disorders in farming – ALLA: agricultural lower limb assessment]. J Ergon Soc Korea. 2010;29(6):933–942. Korean. doi:10.5143/JESK.2010.29.6.933 Kim K. [A study on the farmers’ health status and musculoskeletal workload] [doctoral dissertation]. Seoul: Seoul University; 2008. Korean. Rural Development Administration (RDA). [Research report on risk assessment of agricultural tasks for the development of safety and health management system in rural villages]. Suwon: RDA; 2006. Korean. Rural Development Administration (RDA). [Research report on risk assessment of agricultural tasks for the development of safety and health management system in rural villages]. Suwon: RDA; 2007. Korean. Rural Development Administration (RDA). [Research report on risk assessment of agricultural tasks for the development of safety and health management system in rural villages]. Suwon: RDA; 2008. Korean. Rural Development Administration (RDA). [Research report on risk assessment of agricultural tasks for the development of safety and health management system in rural villages]. Suwon: RDA; 2009. Korean. Rural Development Administration (RDA). [Research report on risk assessment of agricultural tasks for the development of safety and health management system in rural villages]. Suwon: RDA; 2010. Korean. Rural Development Administration (RDA). [Development of agricultural safety management experience program]. Suwon: RDA; 2011. Korean. Rural Development Administration (RDA). [Development of agricultural safety management experience program]. Suwon: RDA; 2012. Korean. Rural Development Administration (RDA). [Development of agricultural safety management experience program]. Suwon: RDA; 2014. Korean. Lee IS, Jung MK, Choi KI. [Comparison of observational posture evaluation methods based on perceived discomfort]. J Ergon Soc Korea. 2003;22(1):43–56. Korean. doi:10.5143/JESK.2003.22.1.043 Lee K-S, Kim J-H, Jung M-S, et al. [Comparison of assessment by OCRA Checklist and RULA at an auto manufacturing plant]. J Ergon Soc Korea. 2007;26(4):153–160. Korean. doi:10.5143/JESK.2007.26.4.153 Lee KS, Yeom JW, Hur HM, et al. [Comparisons of different evaluation tools for musculoskeletal disorders]. 2009 Fall Conference of the Ergonomics Society of Korea; 2009 Dec 06–07; Daegu, Korea. Korean. Kong Y-K, Lee S-J, Lee K-S, et al. [Development of an ergonomic checklist for the investigation of workrelated upper limb disorders in farming – AULA: agricultural upper-limb assessment]. J Ergon Soc Korea. 2011;30(4):481–489. Korean. doi:10.5143/JESK.2011.30. 4.481 Kong YK, Lee SJ, Lee KS, et al. Development of an ergonomics checklist for investigation of workrelated whole-body disorders in farming – AWBA: agricultural whole-body assessment. J Agric Saf Health. 2015;21(4):207–215. doi:10.13031/jash.21.10647