Ergonomic analysis of working postures using OWAS in semi-trailer assembly,applying an individual sampling strategy

In semi-trailer assembly, workers are exposed to several physical risk factors. Awkward working postures have not yet been investigated in semi-trailer assembly, although they are known to be a major risk factor for musculoskeletal disorders. We therefore conducted a comprehensive ergonomic analysis of working postures using the Ovako working posture analysing system (OWAS), with an individual sampling strategy. The postural load in semi-trailer assembly was assessed on the basis of 20,601 observations of 63 workers executing a representative set of nine work tasks. According to the OWAS, the postural load of various working postures and body part positions may have a harmful effect on the musculoskeletal system. We therefore give examples of corrective measures that could improve awkward working postures. Applying an individual sampling strategy was revealed to have advantages over a collective strategy, so this is recommended for future ergonomic analyses.     

An Ergonomie Study on Posture-Related Discomfort Among Preadolescent Agricultural Workers of West Bengal,India

In India, particularly in West Bengal, preadolescents are primarily associated with agricultural work in rural areas. Owing to poor socio-economic conditions, they are compelled to carry out a considerable number of manual, rigorous tasks in agricultural fields. The main aim of this study was to investigate postures adopted by preadolescent agricultural workers during individual agricultural activities and to analyze the causes of discomfort related to those postures. Fifty male and 50 female preadolescent agricultural workers were randomly selected and a detailed posture analysis was performed with the Ovako Working Posture Analysis System (OWAS). It was observed that those workers worked continuously in awkward postures during certain agricultural activities. Consequently they suffered from discomfort in different parts of their body. Even though they were very young, they were likely to suffer from serious musculoskeletal disorders in the future.     

An ergonomic study on posture-related discomfort among preadolescent agricultural workers of West Bengal, India.

In India, particularly in West Bengal, preadolescents are primarily associated with agricultural work in rural areas. Owing to poor socio-economic conditions, they are compelled to carry out a considerable number of manual, rigorous tasks in agricultural fields. The main aim of this study was to investigate postures adopted by preadolescent agricultural workers during individual agricultural activities and to analyze the causes of discomfort related to those postures. Fifty male and 50 female preadolescent agricultural workers were randomly selected and a detailed posture analysis was performed with the Ovako Working Posture Analysis System (OWAS). It was observed that those workers worked continuously in awkward postures during certain agricultural activities. Consequently they suffered from discomfort in different parts of their body. Even though they were very young, they were likely to suffer from serious musculoskeletal disorders in the future.     

A comparison of three observational techniques for assessing postural loads in industry.

This study aims to compare 3 observational techniques for assessing postural load, namely, OWAS, RULA, and REBA. The comparison was based on the evaluation results generated by the classification techniques using 301 working postures. All postures were sampled from the iron and steel, electronics, automotive, and chemical industries, and a general hospital. While only about 21% of the 301 postures were classified at the action category/level 3 or 4 by both OWAS and REBA, about 56% of the postures were classified into action level 3 or 4 by RULA. The inter-method reliability for postural load category between OWAS and RULA was just 29.2%, and the reliability between RULA and REBA was 48.2%. These results showed that compared to RULA, OWAS, and REBA generally underestimated postural loads for the analyzed postures, irrespective of industry, work type, and whether or not the body postures were in a balanced state.     

A Multilevel Approach to Manual Lifting in Manufacturing Industries

Musculoskeletal injuries are often the consequences of wrong postural configurations used during Manual Materials Handling (MMH). This eventually leads to a large payout of worker’s compensation and loss of production time. A simulated study of back injury risks has been carried out on seven selected manufacturing industries to identify and evaluate harmful working postures. For each MMH task, Ovako Working Posture Analyzing System (OWAS) codes have been identified with the help of motion study pictures. Also, Chaffin's biomechanical model was used to calculate L5/S1 load compression values on the spine during MMH activities. The multilevel approach adopted was a combination of OWAS and Chaffin’s biomechanical model. The application of a digitizer enabled us to identify the coordinates and it made a subsequent evaluation of the angles of each body link possible.     

Assessment of Physical Load at Work Sites: A Finnish–German Concept

The aim of this article is to introduce a set of work physiology methods for the assessment of physical load at the work site and to consider (a) their relevance for different types of muscular work, and (b) their feasibility for occupational health and safety practitioners. The results of an ergonomic intervention study for the reduction of workload associated with various manual materials handling tasks were used for the evaluation of the feasibility and sensitivity of the measurements of heart rate, the Edholm and OWAS methods, and the ratings of overall and local perceived exertion. The methods proved feasible, although time consuming, and their sensitivity for the quantification of small changes in physical workload was limited. Despite these shortcomings, these methods can be used by occupational health and safety practitioners when their strategy and data collection techniques are developed further. In conclusion, there are relevant and feasible methods fora reliable work-site assessment of cardiorespiratory and postural load related to the activation of large muscle masses. On the other hand, field methods for the quantification of local static workload and repetitive type of workload with small muscle masses are scarce.     

Comparisons of ergonomic evaluation tools (ALLA,RULA, REBA and OWAS) for farm work

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.     

Occupationally Oriented Medical Rehabilitation and Hairdressers’ Work Techniques–A one-and-a-half-year follow-up

This study examined changes in work techniques and musculoskeletal symptoms after occupationally oriented medical rehabilitation arranged for 21 hairdressers who were experiencing neck-shoulder or back pain but were still able to work. OWAS (Ovako Working Posture Analysing System) analyses of working postures and questionnaire data were obtained at the beginning of the courses and one and a half years later. The participants worked with their back bent and twisted or their arms at or over shoulder level more seldom (p < .0001) at the end of the follow-up than at the beginning of the rehabilitation. Subjective work-related physical and mental strain had decreased by 45.4% (p < .001) and 27.1% (p < .05), respectively, and subjective neck and back pain by 40.0% (p < .0 1 ) and 45.3% (p < .01). respectively. This’study suggests that occupationally oriented medical rehabilitation can have significant and long-lasting effects on the rehabilitee’s work techniques and subjective well-being.     

Perceptions of postural stability after transitioning to standing among construction workers

Falls are a leading cause of fatal and nonfatal injuries in the construction trades. This study explored construction workers’ self-reports of postural stability upon standing after working in different postures. One hundred and eighty-nine workers in 10 construction trades provided stability ratings by completing a written questionnaire. Additional data collected included age, gender, years of experience, and rating of overall balance. Construction workers rated their overall balance as high, furthermore, no difference was found between trades or age groups. Significant differences in stability ratings were provided for the various postures. The most commonly used non-erect postures (bent over at waist, squatting, and forward kneeling) resulted in the largest self-reports of instability. Sitting on elevated surface and sitting on level surface resulted in the highest levels of self-reported stability and are recommended when maintaining balance is a concern. Differences associated with construction trade and age were also found, but were thought to be attributed to differences in tasks performed since no differences were found when each posture was analyzed separately. The results suggest that the working posture used to complete a task affects the postural stability upon standing regardless of construction trade and age of worker. Findings may lead to recommendations for redesign of tasks or tools to reduce the use of certain working postures, particularly in high-risk environments such as construction.     

Cardiovascular Strain of Sawmill Workers in South-Western Nigeria

This study aimed to assess cardiovascular strain during sawmilling operations in terms of physical workload, based on heart rate changes. We measured resting and working heart rates and calculated cardiovascular load (%CVL), cardiovascular strain (%CVS) and relative heart rate (%RHR) in 35 sawmill workers. Based on heart rate only, the work in sawmills was classified as very heavy and extremely heavy. Similarly, a high-level category was recorded for %CVL and a very high range for %CVS. Thus, the workload in sawmill operations is usually very high and can lead to physiological strain of the workers. There is a need to redesign the work content of this occupation to prevent excessive strain in the workers, as this will increase their productivity and reduce their health risk.     

Participatory ergonomics and an evaluation of a low-cost improvement effect on cleaners' working posture.

Cleaning is a highly physically demanding job with a high frequency of awkward postures and working environments as contributing risk factors. Participatory ergonomics is a method in which end-users take an active role in identifying risk factors and solutions. The aim of this study was to apply the participatory ergonomics method to identify cleaning problems and to evaluate the effect of a low-cost improvement on cleaners' working postures in an office environment. The results show that the cleaning problem was identified, and the low-cost ergonomics solution suggested by the cleaners was implemented. Thus an improved working environment reduced the number of awkward cleaning postures and the Ovako Working Posture Analysis System (OWAS) action category for floor mopping decreased. It can be concluded that working in an improved environment can lead to better working postures which, in turn, leads to the cleaners' better health and better cleaning results.     

Analysis of postural load during tasks related to milking cows-a case study

The aim of this study was to analyse postural load during tasks related to milking cows of 2 farmers on 2 different farms (one with a manual milk transport system, the other with a fully automated milk transport system) as a case study. The participants were full-time farmers, they were both healthy and experienced in their job. The Ovako Working Posture Analyzing System (OWAS) was used to evaluate postural load and postural risk. Postural load was medium for the farmer on the farm with a manual milk transport system and high for the farmer working on the farm with a fully automated milk transport system. Thus, it can be concluded that a higher level of farm mechanization not always mean that the farmer's postural load is lower, but limitation of OWAS should be considered.     

Physical limitations and musculoskeletal complaints associated with work in unusual or restricted postures: a literature review

INTRODUCTION: The vast majority of ergonomics research has addressed the demands of work in standing or sitting postures, and understandably so. However, many workers (e.g., underground miners, aircraft baggage handlers, plumbers, agricultural workers, mechanics, and others) are often required to adopt postures such as kneeling, stooping, squatting, or lying down for significant periods of the workday. METHOD: A literature search was performed using the ISI Web of Science database (for years 1980-2004). Articles retrieved from this search were evaluated in terms of relevance to assessing physical capabilities of workers in these postures and/or the musculoskeletal epidemiology associated with these postures. RESULTS: Work in unusual and restricted postures was associated with significantly higher rates of musculoskeletal complaints compared to workers not adopting these postures in epidemiology studies (Odds Ratios ranging from 1.13 to 13). Some studies suggested a dose-response relationship, with longer exposures leading to increased musculoskeletal complaints. Physical strength and psychophysical lifting capacity vary significantly as unusual or restricted postures are adopted, with lower lifting capacities evident in the kneeling, squatting, and lying positions. CONCLUSIONS: Workers who adopt unusual or restricted postures appear to be at higher risk of musculoskeletal complaints and often exhibit reduced strength and lifting capacity. Research needs in this area include improved exposure assessment tools, studies of intervention effectiveness, adaptations of the body in response of work in unusual postures, and elucidation of relevant injury pathways. IMPACT ON INDUSTRY: Workers who adopt unusual or restricted postures in their work often experience higher musculoskeletal injury rates. If awkward postures cannot be eliminated in the workplace, jobs should be designed in accordance with the reduced strength and lifting capabilities observed in these postures.     

Combined Effects of Physical Demands and Shift Working on Low Back Disorders Among Nursing Personnel

The aim of this study was to investigate the synergistic effects of physical demands and shift working on low back disorders (LBDs) among nursing personnel. The study used 2 questionnaires: a self-administered questionnaire composed of parts of Nordic musculoskeletal questionnaire to assess LBDs and job content questionnaire to assess physical demands. The participants were divided into 4 groups: from group 1 (low physical demands day workers) to group 4 (high physical demands shift workers). In regression analysis, high physical demands were associated with the prevalence of LBDs independently (OR 4.4, 95% CI [2.40, 8.00] and p < .05), but there was no association between shift working and LBDs (p > .05). Odds ratio in high physical demands shift workers was 9.33 compared to the reference group (p < .001). Calculated synergistic index was 7.37. Simultaneous impacts of shift working and high physical demands may increase the prevalence of LBDs among nursing personnel.     

Impact of posture and upper-limb muscle activity on grip strength

Purpose. The current research was carried out to determine grip strength (GS) with change in posture and upper-limb muscle activity of manual workers and investigate the impacts of these changes. Methods. For the current research, 120 male and 80 female participants were selected and GS was assessed using a digital hand grip dynamometer in various conditions. Results. The outcomes showed that male participants had higher GS as compared to female participants. Maximum GS was found in a standing posture with the fixed forward shoulder at 45°, elbow at 90° and a neutral position of the wrist and forearm for all participants. Conclusions. Higher values of GS were attained in standing postures which may result in attainment of higher performance levels by the workers. The outcomes justify the importance of correct postures during manual work in industries employing traditional methods.     

Indices of ergonomic-psycholsociological workplace quality in the greenhouses of Almería (Spain): Crops of cucumbers,peppers, aubergines and melons

This work uses the Labour Economics and Sociology Laboratory of France (LEST) method to evaluate the ergonomic-psycholsociological quality of work in horticultural greenhouse exploitations in Almería (Spain) with the aim of improving workers’ occupational health. Data on the factors affecting the physical environment, the physical workload, mental workload, psychosocial aspects and the working hours of labourers were collected in 110 greenhouses, 35 of the Almeria parral-plano type and 75 of the raspa y amagado type. The crops raised in these greenhouses were cucumbers (24 greenhouses), peppers (25), aubergines (28), and melons (38). These greenhouses, typical of southeastern Spain, were found not to guarantee workers a comfortable working environment. The type of greenhouse and the crop raised within directly affected the ergonomic-psychosocial conditions of the workers. Suggestions are offered that might improve these conditions.     

Effect of restaurant types on compensation claims for work-related musculoskeletal disorders in France

Objectives. The economic burden of work-related musculoskeletal disorders (WMSDs) is industry specific. The objective was to analyse compensation claims for WMSDs among restaurant workers in France taking into account the type of restaurant. Methods. Data for 2014 were obtained from the French National Health Insurance Fund for Salaried Workers. A chi-square test was used to compare claims, incapacity and lost work day rates in different types of restaurant. Results. Prevalence for WMSDs differed significantly by the type of kitchen: collective restaurant (7.2/1000 workers), traditional restaurant (1.7/1000), and fast food restaurant (1.0/1000). There were more male claimants in traditional restaurant workers (51.0%) than in collective restaurant workers (40.1%) but more female claimants in collective restaurant workers (50.1%) than in traditional restaurant workers (39.4%). Permanent incapacity was significantly more prevalent in collective restaurant workers (49.6%), than in traditional (41.9%) and fast food (8.5%) restaurant workers. In collective restaurant workers, as a percentage, claims, permanent incapacity and lost work days increased with age range or work experience. Conclusions. Prevalence for WMSDs and therefore incapacity and lost work days are different according to the type of restaurant. Preventive strategies should take these differences into consideration.     

Assessment of energy balance against the nutritional status of women carriers in the brickfields of West Bengal

The Indian brick industry is an unorganized sector in which large numbers of migrant women workers are employed. A survey was conducted on 62 women workers working in different brickfields of West Bengal to assess their physiological workload, nutritional profile, total energy expenditure and energy balance. Energy intake was calculated using physiological fuel values of carbohydrate, fat and protein. From the results it is seen that 13% of the sample population falls under severe (grade III) chronic energy deficiency. The average daily consumption of the workers was comparatively lower than their daily energy expenditure, considering the nature of the job which falls under heavy to extremely heavy categories. This negative energy balance is effectively observed in the nutritional anthropometry data. Thus, an immediate ergonomics intervention with better nutrition should be implemented to improve the health status of the workers so they can safely continue to work for a longer period.     

A Comparative Ergonomics Postural Assessment of Potters and Sculptors in the Unorganized Sector in West Bengal,India

Potters and sculptors perform their work in very awkward postures. The purpose of this study was to analyse these postures. The modified Nordic questionnaire was used to analyse musculoskeletal discomfort. Rapid entire body assessment (REBA) and rapid upper limb assessment (RULA) were used to evaluate the subjects’ postures. There were no significant differences between times of discomfort and the group of subjects. However, there were significant differences in discomfort in different body parts. The analysis indicated that various body postures were harmful to the subjects and that there were profound deviations from natural curvature of various body parts due to awkward body postures. Ergonomics intervention was required to improve the quality of life.     

Ergonomics intervention on an alternative design of a spinal board

Nurses are often obliged to work in a 12-hr shift work system. We have decided to check whether such a working system constitutes an excessive load for nurses. On the basis of a questionnaire survey among nurses working in an 8-hr daytime shift system (169 nurses) and in a 12-hr shift (536 nurses), the amount of physical workload, work stress, and after-work activities were compared. Data analysis has shown that a 12-hr shift system is characterized by less significant physical workload but greater mental load. The nurses working in a 2-shift system were more tired after work, but they could spend more time on leisure activities and do housework. The data suggest that there are no significant contraindications for nurses to work in a 2-shift system.