Comparison of risk assessment procedures used in OCRA and ULRA methods

Biomechanical risk factors and subacromial pain provocation in healthy manufacturing workers

Objectives. Work-related musculoskeletal disorders (MSDs) of the shoulder may manifest subclinically. By combining risk assessment and clinical instruments, it may be advisable to recognize workers who may develop more complex MSDs early. This study aimed to evaluate the relationship between biomechanical risk factors and subacromial pain provocation in healthy manufacturing workers. Methods. A cross-sectional descriptive observational study was carried out with workers in the furniture manufacturing industry. The occupational repetitive action (OCRA) checklist was applied to detect risk factors and three clinical tests used to detect subacromial tissue reactivity: the supraspinatus test, the painful arc test and the Hawkins-Kennedy test. Results. The positivity of the clinical tests is higher in the supraspinatus test, followed by the Hawkins-Kennedy test, and lowest in the painful arc test, for both the right and left shoulders. No significant associations were found with the overall OCRA checklist index or specific biomechanical factors. Conclusion. The biomechanical risk factors and the provocation of subacromial pain reviewed in this study were not found to be related. Other physical tests that are more sensitive and adapted to workers at risk of developing musculoskeletal shoulder disorders should be explored.

A Case Study of Ergonomic Risk Assessment in Slovakia with Respect to EU Standard

Attention on work-related musculoskeletal disorders (WMSDs) involves statistical surveys showing an increasing trend in the incidence of WMSDs. Technological development has led to new tools and methods for the assessment of physical load at work. These methods are mostly based on the direct sensing of appropriate parameters, which allows more precise quantification. The aim of this paper is to compare several commonly used methods in Slovakia for the assessment of ergonomic risk reflecting current EU and Slovak legislative regulations. A Captiv wireless sensory system was used at a car headlight quality control assembly workplace for sensing, data acquisition and data processing. During the evaluation of postures and movements at work, we discovered differences in the applicable standards: Decree 542/2007 Coll. (Slovak Legislation), the STN EN 1005-4+A1, and the French standards default in the Captiv system. Standards define the thresholds for hazardous postures with significant differences in several evaluated body segments, which affects the final evaluation of the measurements. Our experience from applying improved risk assessment methodology may have an impact on Slovak industrial workplaces. It was confirmed that there is a need to create uniform standards for the ergonomic risk assessment of body posture, including a detailed description of the threshold values for individual body segments.

Empirical Suitability of Scoring Systems of Observational Techniques for Repetitive Movements Based on Discomfort

This study empirically investigated the effects of repetitive movements of body parts through an experiment, and evaluated the suitability of the scoring systems of the existing observational methods for repetitive movements, based on the experimental results. Eighteen healthy college students participated in the experiment to assess discomfort, wherein joint movement, its repetition, and external load were used as independent variables. Postural loads for 16 postures used in the experiment were assessed using rapid upper limb assessment (RULA) and loading on the entire body assessment (LEBA). Three independent variables, joint motion, its repetition, and external load, as well as the interaction between motion repetition and external load, had significant effects on discomfort. Joint motion and external load significantly affected the RULA grand score, whereas all three independent variables affected the LEBA score. This finding may indicate that LEBA more accurately reflects the effect of repetitive body part movements. Additionally, the scoring systems for repetitive back motions by quick exposure check (QEC) and for repetitive wrist motions via a risk assessment and management tool for manual handling proactively II (RAMP II) may be reasonable based on the results of this study. The findings of this study can be used as reference information for better evaluation of postural loads assessed using the existing observational techniques, and as useful baseline data for the development of a new observational method to accurately assess stress caused by repetitive movements.

Musculoskeletal disorders risk assessment methods: a scoping review from a sex perspective

The evidence points to differences in the impact of musculoskeletal disorders (MSD) in males and females due to different exposure to risk factors and inherent characteristics. To identify risks associated with MSDs, ergonomic assessment is carried out by applying various methods. The aim of this scoping review was to determine to what extent ergonomic assessment methods consider sex-related factors and if they were found to do so, to determine the extent of this consideration. A total of 31 papers on 32 ergonomic assessment methods were analysed in the review. Of these 32 methods, only 6 considered sex as an assessment parameter or when interpreting the results. The results revealed that the limited consideration given to the sex factor in ergonomic methods, together with the different impacts of MSDs and their consequences according to a person's sex, supports the importance of including sex factors in ergonomic assessment methods. Practitioner summary: This scoping review determined to what extent ergonomic assessment methods consider sex-related factors and if they do so, to establish the extent of such consideration. Of the 32 methods analysed, only 6 considered a person's sex. The results revealed that only a limited consideration is given to the sex factor in ergonomic methods.

Ergonomic risk and physiological assessment of plogging activity

BACKGROUND: Plogging, an environment friendly trash workout is a combination of jogging with litter collection. People who are involved in the plogging carry a baggage for collecting the litter. Walking with a weight on one side causes the opposite side of the body to engage for stability and are also exposed to repetitive bending during the activity. OBJECTIVES: The purpose of this study is to evaluate the postural and physiological aspects of plogging activity. METHODS: Thirty six subjects performed the litter collection in stoop, semi-squat, full squat and lunge postures respectively. Postures were analyzed using Rapid Entire Body Assessment (REBA). Physiological aspects of plogging, as well as a comparison of physical activity assessment during jogging and plogging, were investigated using a Polar M430 optical heart rate monitor. Statistical analysis were performed using SPSS version 23. RESULTS: Mean±SD of full squat (5.13±0.59) and lunge (6.64±1.15) posture was found to have lesser risk score in comparison with the other two postures such as stoop (10.31±0.88) and semi-squat (8.11±1.40). Analysis from the Kruskal-Wallis and post hoc test showed that there is no significant interaction between the postures (p < 0.05). Paired Sample t-test showed that the energy expenditure for plogging and jogging are found to be similar (p > 0.05), but the fat percentages of calories burned is more in plogging (p < 0.05). Howerver plogging can be considered as a strenous activity as the % Cardiovascular strain of the activity had a mean value of (99.261%). CONCLUSIONS: Ergonomic interventions are needed to play a vital role in minimizing the musculoskeletal related injuries and the physical strain of the task.

Comparison of LEBA and RULA Based on Postural Load Criteria and Epidemiological Data on Musculoskeletal Disorders

Various observational methods have been developed and applied in industrial settings with the aim of preventing musculoskeletal disorders (MSDs). 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. 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. 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. 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.

Systematic Comparison of OWAS, RULA, and REBA Based on a Literature Review

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). The comparison was based on a literature review without time limitations and was conducted on various factors related to observational methods. The comparisons showed that although it has a significant limitation of comprising only two classifications for the leg postures, (1) the RULA is the most frequently used method among the three techniques; (2) many studies adopted the RULA even in evaluation of unstable lower limb postures; (3) the RULA assessed postural loads as higher risk levels in most studies reviewed in this research; (4) the intra- and inter-reliabilities for the RULA were not low; and (5) the risk levels assessed by the RULA were more significantly associated with postural load criteria such as discomfort, MHTs and % capable at the trunk, and MSDs.

Ergonomic Risk Assessment during an Informal Hand-Made Cookware Operation: Extending an Existing Model

The work conducted in the informal sector is highly variable within and between days. Characterizing ergonomic exposures remains a challenge because of unstructured work settings and schedules. The existing ergonomic risk assessment tools have been widely used in formal work settings with a narrow range of exposure, and for predefined tasks that primarily constitute a daily routine. There is limited information in the literature on how they have been applied in informal workplaces. The aim of this study was to extend an existing risk assessment tool and to evaluate the applicability of the extended tool by assessing ergonomic exposure related to hand-made cookware operations. Eighteen hand-made cookware makers were recruited from six sites. A walkthrough risk assessment questionnaire was used to collect information on workers, tasks, work stations and workplace structures. The Rapid Upper Limb Assessment (RULA) screening tool was extended by including duration and vibration. An action priority matrix was used to guide intervention. According to the RULA action levels, the workers required investigation and changes soon, and immediate investigation and changes. The use of an action priority matrix was appropriate, and indicated that all the workers assessed were within the high to very high exposure domain and required immediate corrective measures. The methodology used proved to be an effective and reliable strategy for identifying ergonomic exposure among hand-made cookware makers.

Agreement between observed and interview-based exposure to ergonomics factors for the upper extremities in employees of a package sorting plant

Aim of the study was to estimate agreement between observational and interview-based exposure to ergonomic factors at work. Thirty-two male workers employed in a logistics hub were interviewed through the OCRA check-list on exposure to ergonomic factors in one of six work tasks. Observations of workers in each work task, based on the same OCRA check-list, were used to assess exposure in that task. Agreement between observed and interview-based scores of the check-list OCRA index, as well as of frequency and posture, was estimated both at individual and task group level through the Intraclass Correlation Coefficient (ICC). At work task level, high concordance was found between observed and interview-based scores for all the exposures examined, while at the individual level agreement was moderate. These results suggest that exposure assessment through interviews based on the OCRA check-list is a valid method, which could be used as a workstation screening tool. Practitioner summary: The study aimed to evaluate agreement between observational and interview-based exposure to ergonomic factors at work, assessed through the OCRA check-list on 32 male workers. Agreement was found at least moderate, suggesting that interview-based exposure assessed through the OCRA check-list could be used as a proxy of observations for workstation screening. Abbreviations: ART: assessment of repetitive tasks; CI: confidence intervals; EAWS: European assembly worksheet; ICC: intraclass correlation coefficient; ISO: International Standards Organization; OCRA: occupational repetitive actions; ULRA: upper limb risk assessment; WUEMSDs: work-related upper extremity musculoskeletal disorders.

A model for predicting the risk of musculoskeletal disorders among computer professionals

Objective. This study aimed to develop a model for predicting the risk of musculoskeletal disorders among computer professionals. Materials and methods. A preliminary study with a modified Nordic musculoskeletal questionnaire was conducted to identify the risk in different body parts of the professionals during their work. A discrete postural evaluation of the dynamic postures involved in the work was assessed using rapid upper limb assessment. Postural, physiological and work-related factors were considered as attributes of the model. The model was developed using various machine learning algorithms, and was then tested and validated. Results. The postural factor of the computer professionals was found to be significantly (p < 0.01) correlated with the musculoskeletal disorders. Results of the logistic regression analysis showed that physiological and work-related factors were also significantly (p < 0.05) associated with musculoskeletal disorders. The Random Forest algorithm and Naïve Bayes Classifier predicted the risk of musculoskeletal disorders with the highest accuracy (81.25%). Conclusion. Postural, physiological and work-related factors contribute to the development of musculoskeletal disorders. The Random Forest algorithm or Naïve Bayes Classifier model developed based on these factors could be used to accurately predict the risk of musculoskeletal disorders among computer professionals at any instance of time, during their work.

The biomechanical overload of the upper limb: a neglected occupational hazard in animal facility operators

Data on biomechanical overload of the upper limb in animal facility operators are currently scanty. We decided to study this risk in a university animal facility. Eleven different tasks performed by operators were identified. For each of them, the biomechanical overload of the upper limb was evaluated by applying 4 different methods frequently used, hypothesising a task duration of 4 and 8 h. Then two 'typical' real working days of the examined facility were reconstructed, and the risk for operators was calculated using the OCRA Index, Checklist and Mini-Checklist. Considering the specific tasks, the results show some difference among methods, but the overall results show an acceptable/slight risk of biomechanical overload of the upper limb in animal facility operators during typical working days. Practitioner Summary: Upper limb biomechanical overload (UL-BO) is a neglected risk in animal facilities. In a university facility, 11 different tasks were identified, and 2 typical working days were analysed. Even if some task at increased risk may exist, during typical working days,  the overall results show that the risk of UL-BO in operators can be considered usually acceptable or, at worst, slight.

Comparative study of upper limb load assessment and occurrence of musculoskeletal disorders at repetitive task workstations

This study explored the relationship between subjectively assessed complaints of pain in the arm, forearm and hand, and musculoskeletal load caused by repetitive tasks. Workers (n=942) were divided into 22 subgroups, according to the type of their workstations. They answered questions on perceived musculoskeletal pain of upper limbs. Basic and aggregate indices from a questionnaire on the prevalence, intensity and frequency of pain were compared with an upper limb load indicator (repetitive task index, RTI) calculated with the recently developed Upper Limb Risk Assessment (ULRA). There was relatively strong correlation of RTI and general intensity and frequency of pain in the arm, and general intensity and frequency of pain in the arm and forearm or prevalence of pain in the arm. Frequency and intensity of pain in the arm were weakly correlated. An aggregate indicator of evaluation of MSDs, which was calculated on the basis of the prevalence, intensity and frequency of pain, was to a higher degree associated with the musculoskeletal load of a task than basic evaluative parameters. Thus, such an aggregate indicator can be an alternative in comparing subjectively assessed MSDs with task-related musculoskeletal load and in establishing limit levels for that load.