A fuzzy assembly line balancing problem with physical workload constraints

Objectives: This study aimed at measuring the mental and physical workload and its association with the prevalence of wrist disorders. Methods: This cross-sectional study was conducted on 120 female workers working in the assembly line of a porcelain company. The mental and physical workloads and also the prevalence of wrist disorders were measured using the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) questionnaire, the OCRA method, and the Nordic musculoskeletal questionnaire for wrists and hands, respectively. Results: The results showed that 63.3% of the participants had discomfort in their wrist and hands. The Mann-Whitney test results showed that OCRA risk levels were significantly higher in those with wrist pain than those without. The NASA-TLX results revealed that the physical demands and effort (78.79 ± 19.562 and 78.37 ± 20.002, respectively) had the higher scores among the 6 subscales of NASA-TLX, which were significantly higher in those with wrist pain. Conclusions: The findings suggested a high rate of physical and mental workloads and also the wrist disorders in the assembly line workers of the porcelain company. It seems that mental workload is one of the risk factors associated with the incidence of MSDs. Therefore, the high amount of mental workload should be considered as a risk factor.

Introduction: Musculoskeletal disorders complaints occur due to excessive muscle contraction, excessive workloads and monotonous movements such as when nurses perform various nursing task such as moving patients, carrying patients from bed to wheelchair, awkward posture during infusion placement. This study aims to determine the correlation between physical workload and musculoskeletal disorders complaints among nurses at Regional General Hospital (RSUD) of Indramayu District in 2019. Methods: The design of this study uses quantitative with cross sectional. The method of data collection was crried by means of interview using the Nordic Body Map (NBM) questionnaire and observing the pulse calculation manually using a watch. Among the populations of 348 nurses, the samples of 75 nurses were selected based on the accidental sampling method. Statistical test used the chi-square test with a confidence level of 95% (α=0.05). Results: The study findings showed that most of 40 nurses who had heavy physical workload, 35 nurses (87.5%) had high musculoskeletal disorders complaints and 5 nurses (12.5%) had moderate musculoskeletal disorders complaints. On the other hand, of the 35 nurses who had moderate physical workload, 26 nurses (74.3%) experienced moderate musculoskeletal complaints and 9 nurses (25.7%) had high musculoskeletal disorders complaints. Chi-Square test results obtained p value = 0.000 (p <0.05). Thus, it can be concluded that there was a significant correlation between physical workload and musculoskeletal disorders complaints among nurses. Conclusion: The heavier the physical workload, the higher the musculoskeletal disorders complaints among nurses.Keywords: musculoskeletal disorders, nurses, physical workload

Introduction: Work-related Musculoskeletal Disorders are common among healthcare workers especially nurses, and because they are preventable, attention should be raised towards the importance of training as the first step for improving both health of nurses and quality of patient care thus decreasing both human and economic costs. Aim of work: This study was conducted to assess the prevalence of workrelated musculoskeletal disorders, to implement an ergonomic training program and to evaluate the effect of ergonomic intervention program nurses’ physical workload and work style. Materials and methods: intensive care units’ nurses from two hospitals participated in the study and completed questionnaires including Nordic musculoskeletal questionnaire, physical work load questionnaire and Workstyle Short Form questionnaire. An intervention training program was conducted in one hospital on ergonomic principles, musculoskeletal disorders, patient manual-handling techniques, stretching and relaxation exercises for major body regions, other hospital regardedas control. Evaluation of the effect of the program was conducted after 6 months. Results: Low back pain was the commonest cause of job change among intervention and control hospitals nurses (11.9%, 13.0% respectively). Most of nurses reported a moderate physical workload. There was significant reduction in physical work load and improvement in the Work style after intervention (p < 0.001). Conclusion: Considering the fact of decreased resources needed to equip the Egyptian hospitals with advanced patient handling equipment and as a glance of hope to improve nurses’ health and safety while performing their job, our ergonomic training program showed significant improvement in nurses’ activities that will help in reducing Work-related Musculoskeletal Disorders (WRMSDs) and thus improvement of their quality of life.

Enumerations and stability analysis of feasible and optimal line balances for simple assembly lines

In the coming decades, demographic, economic and social changes will result in an increased proportion of elderly persons in the workforce in most industrialized countries. This trend is causing growing interest in the problems of the aging worker in current employment. The objective of this particular paper is to provide more insight into the impact of aging on the balance between physical work capacity and physical workload. To this end, the scientific literature in the field is reviewed and ordered by means of a specific conceptual model of "aging and physical workload". A progressive decline in physical work capacity, characterized by diminished aerobic capacity and muscular capacity, has consistently been reported. However, inter-individual differences appear to be considerable. The question of whether there are systematic differences in physical work demands between younger and older workers within occupations has been answered vaguely. Conflicting results in this matter bring into discussion the role of the actual working method as one of the determinants of the physical workload. An age-related imbalance between physical workload and physical work capacity is suggested to result in a chronic overload, increasing the risk of long-term health effects such as musculoskeletal complaints and disorders. For many aging workers in physically demanding occupations, extreme physical workloads, increasing the risk of disease or disablement, are still reported. The multiconceptual study of aging and physical workload in the present paper reveals several possibilities for preventive measures. However, as information is still lacking, additional research is needed, in particular on the onset and development of long-term effects on health in relation to age and work demands.

This study investigates associations of an adverse psychosocial work environment with musculoskeletal pain among German police officers in special forces. Analyses are based on a survey of 480 officers in special police forces (mainly special assignments and mobile units). An adverse psychosocial work environment is measured by the effort-reward imbalance model that identifies "high effort/low reward" working conditions. Musculoskeletal pain is assessed by means of a validated questionnaire (12 months and 7 days prevalence). Analyses confirm that police work is a stressful occupation. Multivariate logistic regression analysis indicates a twofold risk for neck, back and hip pain among police officers defined by an imbalance of high effort and low reward at work after adjustment for age, gender, socio-economic status, and physical work load.

A goal programming mixed-model line balancing for processing time and physical workload

In Germany, several tools for the risk assessment of physical workload are available for different applications. Besides different screening methods, there are technical systems that can be used in the field and/or laboratory. The focus of the work of the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) is located on the risk assessment of physical workload using technical measurements (CUELA 1 ). By providing assessment procedures for different body regions, an important gap in the prevention of work-related MSDs is to be closed here. Regarding risk assessment for upper limb MSDs, the IFA develops procedures for evaluating workload on the wrist, elbow and shoulder. To newly develop an assessment procedure for the elbow load a systematic review was carried out, for instance. The activities for assessing the shoulder load are also part of the PEROSH joint research project ‘PEROSH recommendations for procedures to measure occupational physical activity and workload’ having one focus on the assessment of upper arm elevation at work with technical systems. 2 Within the framework of a joint project of the Federal Institute for Occupational Safety and Health (BAuA) and the German Social Accident Insurance (DGUV) (MEGAPHYS – multilevel risk assessment of physical workload) it is intended to use the IFA assessment procedures for about 120 workplaces where the physical workload was measured by CUELA. The workload data is for example to be correlated with subjectively perceived strain and complaint data from questionnaires, interviews and physical examinations collected from about 1000 employees. References . Ellegast R, Hermanns I, Schiefer C. Workload assessment in field using the ambulatory CUELA system. In (Duffy VG ed.). Second International Conference on Digital Human Modelling – ICDHM 2009 : Held as Part of HCI International 2009July 19–24. San Diego. Berlin: Springer:221–6. . http://www.perosh.eu/research-projects/perosh-projects/perosh-recommendations-for-procedures-to-measure-occupational-physical-activity-and-workload/

Introduction: Occupational health must be considered in the workplace. Cases of overweight and obesity among workers in the manufacturing sector have increased. This study analyzes the relationship between physical workload and personal factors related to nutritional status among manufacturing workers. Methods: This study used an observational analytic study with a cross-sectional design. The variables of this study were physical workload, nutritional status, and personal factors such as gender, educational level, exercise habits, and smoking habits. The sample in this study was 239 workers in the manufacturing industry, and it was obtained using random sampling techniques. Data were analyzed using the Spearman correlation and coefficient contingency test. Result: More than half of the total cases of overweight and obesity occur in manufacturing workers who have a low physical workload. More than half of the respondents are female, do not have a high school education, and have never exercised. Most do not have a smoking habit. The results showed that physical workload (p=0.001), exercise habits (p=0.001), gender (p=0,004), and educational level (p=0.037) were related to nutritional status. In contrast, manufacturing workers' smoking habits were not associated with nutritional status (p&gt;0.05). Conclusion: Physical workload, exercise habits, gender, and educational level have a relationship with nutritional status among workers, it is recommended that workers must increase their exercise routine such as implementing scheduled sports shifts for workers and providing sports facilities in companies so the case of being obesity can be decreased.

BackgroundIt is usually assumed that musculoskeletal pain is associated with both the physical workload and the psychosocial work environment, as well as with personal and lifestyle factors. This study aims to ascertain the prevalence of musculoskeletal pain in women with varying or different occupational exposures, and to explore the associations between musculoskeletal pain and the occupational and personal factors.MethodsA questionnaire on physical, psychosocial and individual factors was answered by 1591 women in five occupational groups with contrasting occupational exposures (teachers, anaesthetic, theatre, and assistant nurses, and sonographers). The outcome measure was musculoskeletal pain (in a new model based on frequency and intensity of complaints the preceding year) from the neck, shoulders, hands, lower back and feet.ResultsNeck pain was equally frequent among teachers, assistant nurses and sonographers, and less frequent in anaesthetic and theatre nurses. The sonographers experienced the highest prevalence of shoulder pain, while the assistant nurses were the most affected in the wrists and hands, lower back, and feet.The teachers reported the highest scores in most of the psychosocial dimensions. The theatre nurses scored highest in strenuous work postures and movements (mechanical exposure index, MEI), and the assistant nurses in physical activity and lifting (physical exposure index, PHYI). Multivariable models in the total population showed that both the physical workload and the psychosocial work environment were associated with pain in all body regions, though different factors affected different regions. Pain in the neck, shoulders, hands and lower back was strongly associated with a high MEI and high job demands, while pain in the feet was associated with a high PHYI and a high BMI. A young age was associated with pain in the neck, and an older age was associated with pain in the hands and feet. Lack of time for personal recovery was associated with pain in the shoulders and lower back.ConclusionsThe occupational groups were affected differently and need different protective measures. For the teachers, the psychosocial work environment should be improved. The surgical staff and sonographers require measures to mitigate lifting and constrained postures.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-016-0883-4) contains supplementary material, which is available to authorized users.

Occupational hazards exist, if the design of the work situation is not in accordance with ergonomic design principles. At assembly lines ergonomics is applied to the design of work equipment and tasks and to work organisation. The ignoring of ergonomic principles in planning and design of assembly work leads to unfavourable working posture, action force and material handling. Disorders of the musculoskeletal system are of a common occurrence throughout Europe. Musculoskeletal disorders are a challenge against the background of disabled workers. The changes in a worker's capability have to be regarded in the conception of redesigned and new assembly lines. In this way ergonomics becomes progressively more important in planning and design of vehicles: The objective of ergonomic design in different stages of the vehicles development process is to achieve an optimal adaptation of the assembly work to workers. Hence the ergonomic screening tool "Design Check" (DC) was developed to identify ergonomic deficits in workplace layouts. The screening-tool is based on the current ergonomic state of the art in the design of physical work and relevant EU legal requirements. It was tested within a federal German research project at selected work stations at the assembly lines at Dr.-Ing. h.c. F. Porsche AG / Stuttgart. Meanwhile the application of the screening-tool DC is transferred in other parts of the Porsche AG, Stuttgart. It is also realized as an ergonomic standard method to perform assembly work in different phases of the vehicle development process.

PurposeThis paper considers the assembly line worker assignment and balancing problem of type-2 (ALWABP-2) with fuzzy task times. This problem is an extension of the (simple) SALBP-2 in which task times are worker-dependent and concurrently uncertain. Two criteria are simultaneously considered for minimization, namely, fuzzy cycle time and fuzzy smoothness index.Design/methodology/approachFirst, we show how fuzzy concepts can be used for managing uncertain task times. Then, we present a multiobjective genetic algorithm (MOGA) to solve the problem. MOGA is devoted to the search for Pareto-optimal solutions. For facilitating effective trade-off decision-making, two different MO approaches are implemented and tested within MOGA: a weighted-sum based approach and a Pareto-based approach.FindingsExperiments over a set of fuzzified test problems show the effect of these approaches on the performance of MOGA while verifying its efficiency in terms of both solution and time quality.Originality/valueTo the author’s knowledge, no previous published work in the literature has studied the biobjective assembly line worker assignment and balancing problem of type-2 (ALWABP-2) with fuzzy task times.

To investigate the exposure-response relationships between alternative frequency weightings of hand-transmitted vibration (HTV) and neck and upper limb musculoskeletal disorders (MSDs) in a cohort of HTV workers. In a three-year longitudinal study, the occurrence of neck and upper limb MSDs was investigated in 249 HTV workers and 138 control men. In the HTV workers, MSDs were related to measures of daily vibration exposure expressed in terms of 8-h energy-equivalent frequency-weighted acceleration magnitude [A(8)]. To calculate A(8), the acceleration magnitudes of vibration were weighted by means of four alternative frequency weightings of HTV. The associations between MSDs, individual characteristics, physical work load other than vibration, and psychological strain were also investigated. The occurrence of upper limb MSDs was greater in the HTV workers than in the controls. After adjustment for potential confounders, the occurrence of elbow/forearm and wrist/hand MSDs increased with the increase in vibration exposure. A measure of model selection did not reveal any substantial difference in the performance of the alternative frequency weightings of HTV for the prediction of neck and upper limb MSDs. In the study population, age, hard physical work load, and poor psychological well-being were associated with both neck and upper limb MSDs. In this study, there was evidence for significant exposure-response relationships between HTV exposure and MSDs in the distal sites of the upper limbs. There were no differences in the prediction of neck and upper limb MSDs between measures of daily vibration exposure calculated with alternative frequency weightings of acceleration magnitude.

Workers involved in charcoal production face working conditions that require high energy expenditure, with activities involving moving and lifting loads, inadequate postures, repetitiveness, and consequently, the risk of developing musculoskeletal disorders. These factors are combined with adverse environmental conditions, such as intense heat, which further exacerbates health risks. This study aimed to assess the impact of work relationships in charcoal production on the physical integrity and health of workers, through the application of ergonomic tools. Factors such as thermal overload, physical workload, biomechanical factors, and the risk of developing repetitive strain injuries (RSI) or work-related musculoskeletal disorders (WMSD) were evaluated. The results showed that the physical workload of workers varied from moderate to heavy, depending on the activity phase, with a high risk of developing RSI and spinal injuries, especially during the oven filling process. Additionally, the observed thermal overload exceeded the legal limits, making the work unsuitable without the implementation of appropriate control measures to ensure worker safety and health.

The impact on musculoskeletal disorders of changing physical and psychosocial work environment conditions in the automobile industry