Ergonomic Risk Assessment Research Articles

Automated postural ergonomic risk assessment using vision-based posture classification

Construction workers are at high risk of work-related musculoskeletal disorders (WMSDs) due to physically demanding manual-handling tasks in awkward postures. Although existing observational methods to identify ergonomic risks are inexpensive and easy to use, they are seldom used in construction sites because they are time-consuming, subject to observer bias, and require well-trained analysts. To address these drawbacks, this paper proposes a vision-based method to automatically classify workers' postures for ergonomic assessment. Specifically, it proposes a vision-based method that eliminates the need to collect extensive training-image datasets by employing classification algorithms to learn diverse postures from virtual images, and then identifies those postures in real-world images. The experimental tests showed about 89% classification accuracy in automatically classifying diverse postures on images, confirming the usefulness of virtual training images for posture classification. The proposed method has potential for automated ergonomic risk analysis, and could help to prevent WMSDs during diverse occupational tasks.

Construct validity, internal consistency and test-retest reliability of ergonomic risk assessment for musculoskeletal disorders in office workers (ERAMO)

Musculoskeletal disorders (MSDs) have a multifactorial etiology, therefore, their assessment should consider all of individual, physical and psychosocial factors. The Ergonomic risk assessment for musculoskeletal disorders in office workers (ERAMO) is a few specific tools available to evaluate the nature and occurrence of MSDs in office workers and the impact of individual and ergonomic aspects of office workers. The purpose of this study was to perform a construct validity (confirmatory factor analysis; CFA) and verify the reliability, internal consistency of the ERAMO in office workers. A sample of 300 workers from two of government enterprise in Bangkok, Thailand participated in this validation and internal consistency analysis. Intraclass correlation coefficient was used for the statistical analysis of test-retest reliability. The calculation of internal consistency, reproducibility provided evidence of reliability and lack of redundancy. The psychometric properties of the ERAMO were assessed using CFA, which revealed 3 models. For 2 models, the comparative fit index (CFI), goodness-of-fit index (GFI), and non-normed fit index (NNFI) each achieved 0.90, the Chi-square and root mean square error of approximation (RMSEA) demonstrated better values. The results provided this ERAMO tool is a choice that can use for ergonomic risk assessment in office workers. Supplemental data for this article is available online at https://doi.org/10.1080/1463922X.2021.1922780 .

Musculoskeletal disorders and selecting an appropriate tool for ergonomic risk assessment in the dental profession.

Work-related Musculoskeletal Disorders (WMSDs) are major challenges in the occupational health services industry. Dental practitioners are regularly subjected to ergonomic risks, which can cause Musculoskeletal Disorders (MSDs) in various body regions. This comparative cross-sectional study aimed to investigate MSDs and select a proper ergonomic risk assessment method in dental practice. This study was conducted on 70 dentists and 70 administrative staff of dental offices (comparison group) from Shahroud, Iran. The Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) and two observational ergonomic risk assessment methods, including Quick Exposure Check (QEC) and Rapid Entire Body Assessment (REBA), were utilized. The results suggested that the mean score of musculoskeletal discomforts was significantly higher in dentists than in the administrative personnel. Additionally, the results of multiple regression analysis technique inferred that job tenure, working hours, and age had a significant impact on total MSDs. Regular exercise was found to significantly reduce neck discomfort complaints. It was also found that QEC was more effective in predicting musculoskeletal discomforts compared to REBA. Considering the high incidence of WMSDs in dentists, various interventional measures revolving around ergonomically redesigned workstations, enhanced physical working conditions, and ergonomic training courses are suggested.

A Wearable Sensor-Based Platform for Surgeon Posture Monitoring: A Tool to Prevent Musculoskeletal Disorders

Surgeons are workers that are particularly prone to the development of musculoskeletal disorders. Recent advances in surgical interventions, such as laparoscopic procedures, have caused a worsening of the scenario, given the harmful static postures that have to be kept for long periods. In this paper, we present a sensor-based platform specifically aimed at monitoring the posture during actual surgical operations. The proposed system adopts a limited number of Inertial Measurement Units (IMUs) to obtain information about spine and neck angles across time. Such a system merges the reliability of sensor-based approaches and the validity of state-of-the-art scoring procedure, such as RULA. Specifically, three IMUs are used to estimate the flexion, lateral bending, and twisting angles of spine and neck. An ergonomic risk index is thus estimated in a time varying fashion borrowing relevant features from the RULA scoring system. The detailed functioning of the proposed systems is introduced, and the assessment results related to a real surgical procedure, consisting of a laparoscopy and mini-laparotomy sections, are shown and discussed. In the exemplary case study introduced, the surgeon kept a high score, indicating the need for an intervention on the working procedures, for a large time fraction. The system allows separately analyzing the contribution of spine and neck, also specifying the angle configuration. It is shown how the proposed approach can provide further information, as related to dynamical analysis, which could be used to enlarge the features taken into account by currently available approaches for ergonomic risk assessment. The proposed system could be adopted both for training purposes, as well as for alerting surgeons during actual surgical operations.

Postural Ergonomic Risk Assessment and Work-related Musculoskeletal Symptoms Among Surgeons

Background: Work-related musculoskeletal disorders (WMSDs) develop mainly because of poor work ergonomics. Surgeons are much prone to develop the musculoskeletal symptoms due to the nature of their precise work linked with prolong postures. Objectives: To assess the level of postural ergonomic risk exposure and frequency of work-related musculoskeletal symptoms among Surgeons. Methods: This was an observational, descriptive cross-sectional survey conducted among surgeons (n=100) working in hospitals of Rawalpindi and Islamabad, Pakistan. Convenient sampling technique was used. Structured survey questionnaire was used to collect demographic data and work details of surgeons. Pre-validated tools such as Quick Exposure Check (QEC) and Body Mapping Tool were also used. SPSS version 21 was used for data entry and analysis. Results: More than half of the surgeons’ working posture exposed them to high 49(49%) and very high ergonomic risk 15(15%). The mean of Quick Exposure Check score was 55.71±14. Majority of the surgeons 64(64%) requires urgent and immediate change of their work posture. A significant difference of QEC score (p= 0.001) between males and females was found. Statistically significant difference (p=0.002) of QEC score among Surgeons. 64(64%) of the participants have reported work-related body pain in lower back 35(35%), neck 29(29%), shoulder 16(16%), wrist 15(15%), ankle 15(15%), upper back 14(14%), hip pain 9(9%), knee 9(9%) and elbows 5(5%). Conclusion: It is concluded that work- related posture puts surgeons at higher ergonomic risk. Most of them were experiencing work-related musculoskeletal pain in some of their body regions.

Prevalence of musculoskeletal disorders, ergonomics risk assessment and implementation of participatory ergonomics program for pistachio farm workers.

Background and objectives: Pistachio farmers are exposed to a variety of risk factors for musculoskeletal disorders (MSDs). However, no study has been conducted to investigate MSDs in pistachio workers. Therefore, in the present study, besides investigating the prevalence of MSDs and their ergonomic risk factors, the participatory ergonomics (PE) method is used to provide an intervention program to reduce MSDs in this population in harvesting and processing pistachio. Methods: The present study was conducted in two phases. In the first phase 138 workers participated. The prevalence of MSDs was assessed with Nordic Musculoskeletal Questionnaire and the ergonomic risk factors was identified with ManTRA method. In the second phase PE was used to perform ergonomic interventions for reducing MSDs and the effect of the intervention was investigated. Sixty-four workers participated in the second phase (32 in the case group and 32 in the control group). Results: The highest prevalence of MSDs was in shoulders (63.7%), followed by the lower back (63%) and wrists/hands (52.1%). The comparison showed that after implementing the PE intervention program, the prevalence of MSDs in the intervention group was not significantly different from that in the control group. However, in the reassessment by the ManTRA method for five tasks that were identified as high risk in the first phase, a decrease in ManTRA final score was observed for all the five tasks. Conclusions: MSDs were prevalent in all body regions of workers. After implementing PE interventions exposure to ergonomic risk factors decreased.

Instrumented Ergonomic Risk Assessment Using Wearable Inertial Measurement Units: Impact of Joint Angle Convention

The Rapid Upper Limb Assessment (RULA) is frequently used to monitor body posture for early risk prevention of work-related musculoskeletal disorders. However, RULA measurements that are based on workers’ self-report or external rater observation suffer from low repeatability. Thus, the objective of this study was to investigate the accuracy and repeatability of an inertial measurement unit (IMU) system for in-field RULA score assessment during manual material handling tasks using 3D Cardan angles and 2D projection angles against reference values obtained by a motion-capture camera system. The experimental results showed that for trunk and neck joint angles, the 2D convention had significantly (p < 0.05) smaller root-mean-square error (RMSE), while for other upper-body angles, the convention with significantly smaller RMSE depended on the angle under analysis. Also, the 3D convention showed a “moderate” agreement with the reference system, while the 2D convention showed a “substantial” agreement for two tasks and a “moderate” agreement for one task. Moreover, the intraclass correlation coefficients ranged from 0.82 to 0.94 for the 3D convention and 0.87 to 0.95 for the 2D convention for repeated trials performed by each participant. Therefore, the wearable IMU system, along with the 2D convention, could be considered as an accurate and repeatable ergonomic risk assessment tool.

Simulation-based decision support for production improvement using integrated ergonomic and productivity performance indicators

Workers in the construction manufacturing industry are exposed to labour-intensive tasks with ergonomic risks such as forceful exertion and repetitive motion. Due to increased productivity and repetitive motions resulting from improvement initiatives implemented in offsite construction manufacturing, the investigation of ergonomic risks associated with these changes is needed. In this context, this paper explores an existing panelised floor production line aiming to minimise its ergonomic risks while improving its current productivity rate. Information pertaining to human body motion and productivity is extracted from video recordings. The ergonomic risks associated with specific tasks are identified using two existing ergonomic risk assessment methods: the rapid entire body assessment and the rapid upper limb assessment. A simulation model is used to evaluate various process improvements from the perspective of both ergonomic risks and productivity to support the decision-making process and the prioritisation of process changes in the factory.

Assessment tools analysis of work-related musculoskeletal disorders: strengths and limitations

Musculoskeletal disorders are one of the most common occupational diseases, affecting millions of workers in the European Union and costing employers billions of euros. Researching the relationships and possibilities of optimal mutual adaptation, under given conditions, both of human to his work and of work to humans, in order to increase the technical-economic efficiency, to optimize the conditions of satisfaction, motivation and work results, while maintaining the worker’s state of health also involves, as a basic stage, the assessment of the risks of osteomuscular-articular overload. Starting from a statistical synthesis on the incidence of MSD and the characteristic types of demands, the paper systematizes in a unitary vision the categories of methods, techniques and tools available for recording and evaluating the factors of physical and postural stress of workers. The pointed description of three of the most commonly applied ergonomic risk assessment tools, aimed at developing a synthesis of Strengths-Weaknesses type, which highlights the advantages of methods in counterbalance with their limitations, providing a first basis for selection in order to apply them in the practice of companies that are aware that investing in safety means investing in profit and not losing financial resources and implicitly human, material ones.

Ergonomic risk assessment of the press machine for casava chips in SMEs-Karya Lestari Jaya: A case study

This article discusses about the press machine posture movement effectiveness for cassava chips mold. This research was conducted at Karya Lestari Jaya which is one of the SMES in Tulungagung, East Java, Indonesia. The industry is in trouble with new manual press machine that is too rigid and heavy to handle. The operator complain of pain the arm and forearm. this means the activity has deficient posture when the operator works. This study aims to know the ergonomics risk factors for press machine and determine the best recommendation by the operator and owner SMEs Karya Lestari Jaya suggestion. We conduct a case study by collect the data from observation. We analyze the observation data by RULA (Rapid Upper Limb Assessment). Then, we do interview of eight resource person to get the attribute that required to upgrade the machine. Besides that, we analyze the best recommendation by AHP (Analytic Hierarchy Process). This research result a value of RULA 6 which means the attitude in pressing the dough or working facilities need to repair immediately. There are five phases to determine design there are information phase, creative phase, analyze phase, development phase and recommendation phase and the result of AHP show that the best recommendation is the addition of a pneumatic system in machine press to lighten the lever. In the end, this research can be useful to the company by knowing body posture and evaluating the upgrade machine.

3D fuzzy ergonomic analysis for rapid workplace design and modification in construction

Accurate ergonomic risk assessment is a key to effective workplace design and modification in construction. However, conventional ergonomic risk assessment methods are time-consuming, error-prone, require human subjects, and are hindered by inter- and intra-observer reliability issues. This paper proposes an automated proactive 3D fuzzy ergonomic risk analysis method that accurately quantifies ergonomic risks of continuous motions for rapid workplace design and modification, addressing all of the aforementioned limitations. A specialized rule-based fuzzy inference algorithm is integrated with 3D automated posture-based ergonomic risk assessments to better capture the gradual transitions characteristic of continuous human motion without abrupt changes in risk ratings. This method is tested in a repetitive lifting experiment, which proves its improved accuracy and reliability for ergonomic risk assessment. The results of the analysis are expected to facilitate the enhancement of safety performance, production performance, and market competitiveness in industrialized construction.

A Case Study in Ergonomics by Using REBA, RULA and NIOSH Methods: Logistics Warehouse Sector in Turkey

Employees in the warehouse processes of the logistics sector are engaged in activities such as pushing, pulling and lifting during a day. Intense work tempo, power requirement, working in unsuitable positions, physical factors of working environment adversely affect employees. The aim of this study is to investigate ergonomic risk assessment of a logistic warehouse in the Kocaeli province, located in the Marmara Region. This study was conducted over a sample area where 57 people work in, 5 work processes in a warehouse with a closed area of 8000 m² and all processes were examined during 4 months. Employees' working positions in daily routine were studied by using REBA, RULA and NIOSH as ergonomic risk assessment methods. Furthermore, ambient noise, personal noise, ambient dust, personal dust, vibration, chemical and thermal comfort values were measured with accredited devices.

Ergonomic Analysis By Using REBA, WERA And Biomechanics Method In The Production Process Of Women’s Bags In Small Industry (SME)

This research was conducted at small and medium businesses, namely PT Sumber Karya Indah, a company engaged in the manufacture of women’s bags. There are 10 activities in the process of producing women’s bags. This work system is analyzed using the Nordic Body Map (NBM) method, Rapid Whole Body Assessment (REBA), Work Risk Ergonomic Risk Assessment (WERA), and Biomechanics to see ergonomic risks. The results of the Nordic Body Map questionnaire after working compared to before showed that there were 6 parts of the body of workers that had the highest value, namely the upper neck, buttocks, waist, right hand, left thigh and right thigh. REBA and WERA analysis was carried out on 10 activities to find potentially problematic activities to work health and comfort. The results of the analysis showed that there were 2 activities with high categories of REBA analysis methods, gluing activities (with a score of 10) and sticking activities (with a score of 9). Based on the WERA analysis, the two activities also showed the 2 highest values in the medium category, each with a value of 36 and 34. While the Biomechanical Analysis of worker posture on the gluing activity obtained a thigh muscle pressure score of2440 N and the overall moment was 248 NM towards the left. For sticking activity, the score for the thigh muscle was 1974.2 N and the overall moment was 63.2 NM to the left. Based on the results of these four analyzes, it can be concluded that sticking and sticking activities require immediate ergonomic intervention to reduce occupational health risks.

Ergonomic risk assessment among artisanal cookware manufacturers

Background: The variations presented in the way the informal workers conduct activities present different exposure patterns for each individual trader with large day-to-day variation in activity. Ergonomic risk factors associated with musculoskeletal disorders among artisanal cookware manufacturing have not yet been assessed.Objective: This study aimed to evaluate the ergonomic risk levels, and identify ergonomic factors related to musculoskeletal disorders among artisanal cookware manufacturers in Limpopo and KwaZulu-Natal, South Africa.Methods: Eighteen artisanal cookware manufacturers were recruited from five manufacturing sites in Giyani (Limpopo) and Durban (KwaZulu-Natal) during the months of June and July 2019. Direct observation of the workers was conducted using an ergonomic risk assessment observational tool. Rapid Upper Limp Assessment (RULA) method was used to assess the ergonomic risk factors related to cookware manufacturing. For each task, a score was allocated based on the posture, muscle use and force as per the RULA tool. Results: Ergonomic factors related to musculoskeletal disorders included repetitive motion, extending arms, bending and twisting, long static body posture, contact stress, temperature, noise, vibration, and improper lighting. RULA final scores ranged in magnitude from 4 to 7, with each successive score representing an increased presence of risk factors. The results of this study showed that the artisanal cookware manufacturers had an average final RULA grand score of 7.0, and were only at action level 4 which indicated immediate investigation and work changes.Conclusion: The use of RULA in this study showed that most of the informal workers were exposed to the high ergonomics risk for musculoskeletal disorders. RULA proved to be an effective and reliable method for identifying ergonomic factors related to musculoskeletal disorders among informal workers.

Assessing ergonomic risk factors using combined data envelopment analysis and conventional methods for an auto parts manufacturer.

Occupational injuries are currently a major contributor to job loss around the world and are also costly for businesses. The absence of rational analysis is felt in this area, so mathematical analysis is needed to obtain the logical results of these injuries in order to find gaps or loss points of the industry. This paper assesses the effects of five demographic factors on ergonomic risk and occupational injuries using an integrated mathematical programming approach. The obtained results will help managers to carry out any required corrective actions or establish benchmarks. Two typical ergonomic risk assessment methods, the Quick Exposure Check (QEC) and Rapid Entire Body Assessment (REBA), are applied to assess musculoskeletal disorders in workers. Then, considering the five demographic factors as input variables and risks computed by the QEC and REBA methods as outputs, final risk rates for each decision-making unit (DMU) are calculated using data envelopment analysis (DEA). The importance and weight of each risk factor is analyzed using statistical techniques and analysis of variance (ANOVA). To demonstrate the applicability of the methodology, it is applied to a large auto parts manufacturer. The results revealed that the information obtained by DEA is consistent with those for REBA and QEC, which shows that education, experience and weight are factors that could help reduce ergonomic risks. It is shown that demographic variables such as age, height, weight, education and work experience play an important and effective role in the explanation of ergonomic risk factors.

ASSESSMENT OF WORK POSTURES ON NON-MECHANICAL RICE HARVESTING (CASE STUDIES IN BANTUL AND SLEMAN DISTRICTS, DIY PROVINCE)

Rice harvesting is a high ergonomic risk due to the working position, an awkward posture, and the repetition activity. Rice harvesting causes body pain in the part of low back, hand, and wrist. This study aims to (1) identify the characteristics of non-mechanical rice harvesting; (2) determine the working posture of rice harvesters using the Ovako Working Assessment System (OWAS) method, Quick Exposure Checklist (QEC), Rapid Entire Body Assessment (REBA), Postural Ergonomics Risk Assessment (PERA); and (3) determine the best method to assess harvesters work posture. An observation was conducted to nine of healthy workers in Bantul and Sleman districts, Daerah Istimewa Yogyakarta (DIY) province. The questionnaire was set to collect respondent demographics data. Data for harvester body posture (neck, trunk, leg, wrist, lifting load, shoulder) repetition, duration and force were collected by observation in the field. A sickle was used to cut rice straw, while a manual gepyok and mobile hand thresher was used to threshing rice panicles. Four methods were applied to assess the work posture, i.e., OWAS, QEC, REBA, PERA methods. Based on observation, five workstations were identified: (1) cutting rice straw, (2) transporting rice straw, (3) threshing of panicles, (4) sorting, and (5) packaging and transporting. REBA and PERA showed a similar trend of the ergonomic risk, high to low risk took place in workstation transporting rice straw, packaging and transporting, cutting, and threshing. The assessment of work posture that is most suitable for non-mechanical harvesting methods was the REBA method with an accuracy of 92.9%.

Ergonomic risk assessment based on computer vision and machine learning

We develop a novel method that performs accurate ergonomic risk assessment, automatically computing Rapid Upper Limb Assessment (RULA) scores from snapshots or digital video using computer vision and machine learning techniques. Our method overcomes the limitations in recent developments based on computer vision or in wearable measurement sensors, being able to perform unsupervised assessment handling multiple workers simultaneously, even under sub-optimal viewing conditions (e.g., poor illumination, occlusions, and unstable camera views). The processing workflow uses open-source neural networks to detect the workers’ skeletons, after which their body-joint positions and angles are inferred, with which RULA scores are computed. The method was tested with computer-generated, controlled real-world image datasets, and with freely available videos taken in outdoor working scenarios. The computed RULA scores were in close agreement with the assessments of seven specialists in the field, achieving a Cohen’s κ over 0.6 in most real-world experiments.

Application of AULA Risk Assessment Tool by Comparison with Other Ergonomic Risk Assessment Tools.

Agricultural upper limb assessment (AULA), which was developed for evaluating upper limb body postures, was compared with the existing assessment tools such as rapid upper limb assessment (RULA), rapid entire body assessment (REBA), and ovako working posture analysis system (OWAS) based on the results of experts’ assessments of 196 farm tasks in this study. The expert group consisted of ergonomists, industrial medicine experts, and agricultural experts. As a result of the hit rate analysis, the hit rate (average: 48.6%) of AULA was significantly higher than those of the other assessment tools (RULA: 33.3%, REBA: 30.1%, and OWAS: 34.4%). The quadratic weighted kappa analysis also showed that the kappa value (0.718) of AULA was significantly higher than those of the other assessment tools (0.599, 0.578, and 0.538 for RULA, REBA, and OWAS, respectively). Based on the results, AULA showed a better agreement with expert evaluation results than other evaluation tools. In general, other assessment tools tended to underestimate the risk of upper limb posture in this study. AULA would be an appropriate evaluation tool to assess the risk of various upper limb postures.

Correction to: A new approach for ergonomic risk assessment integrating KEMIRA, best–worst and MCDM methods

Correction to: A new approach for ergonomic risk assessment integrating KEMIRA, best–worst and MCDM methods

TASK ANALYSIS ON MAINTENANCE WORKER (RAIL GRINDER) OF LIGHT RAIL TRANSIT (LRT)

Rail maintenance routines are necessary to enable the all rail operations to achieve its aim in maintaining a safe and efficient operation. The maintenance tasks expose the workers to vibration and noise, as they handle specialized machineries and heavy self-propelled vehicles. Exposure of noise above the permissible exposure limit and over the daily allowable duration may cause noise-induce hearing loss (NIHL). Investigation on the type of task that has high noise level exposure on the maintenance workers was conducted to justify the needs to further detailed of this study. This paper will describe the task analysis on maintenance workers and to identify possible tasks with exposure to high level of noise. It scopes down to grinding crew of the maintenance department of light rail transit. Methods used were real-time sound measurement using a sound level meter, observation and interviews. Then, data were analysed to understand the situation of exposure of noise during rail maintenance. An ergonomic risk assessment was also conducted by adoption of the latest guideline on Ergonomic Risk Assessment (ERA) at Workplace Guidelines recommended by Department of Occupational Safety and Health (DOSH), Malaysia. A hierarchical task analysis (HTA) was generated on the task of the maintenance worker, focusing on rail grinding crew. The newly generated HTA had allowed better understanding about the nature of work and the task conducted by a rail grinder during the work shifts. Tasks involving high noise level was identified. Data recorded shows that the noise level for the blowing activity was relatively high and exceeded the permissible exposure limit of 90dBA. The exposure level was currently controlled by practicing the usage of hearing protection equipment (HPE) and by controlling exposure time in accordance to recommendations of the Factory and Machinery Act (FMA). Thus, it had confirmed that maintenance workers were exposed to high noise levels when performing their daily task. Further studies are needed to investigate the relationship between the duration of exposure and noise-induce hearing loss (NIHL) with consideration of the lifestyles of the maintenance workers.