Iranian Journal of Ergonomics

Introduction: While great efforts have been made to determine the quality of life in hospital staffs, few studies have been conducted to identify the effective factors on the quality of life of these employees. The purpose of the present study was to investigate the relationship between workload and quality of life in hospital personnel.

Material and Methods: In this descriptive-analytical study, 200 staffs were selected randomly from two large hospitals of Tehran University of medical sciences (Imam Khomeini and Shariati hospitals). The data collecting tools were three questionnaires including demographic characteristics, quality of life (SF-36), and NASA-TLX workload. SPSS software (version 18.0) was used to analyze the data by descriptive statistics, and Pearson and Spearman correlation tests.

Results: Based on the findings of the study, the mean total scores of the quality of life and the workload were 50±18 and 69.7±13.9, respectively. The results revealed significant reduction in all dimensions of quality of life in nurses compared with laboratory and operating room staffs. Meanwhile the nurses’ workload scores were higher than the two aforementioned groups (p = 0.001). Moreover, there was a significant inverse relationship between workload and quality of life in hospital staffs (P=0.004, r = -.306).

Introduction: In many sensitive and sophisticated workplaces, human errors are very important. Many events occur annually around the world is evidence to confirm error due to the data processing operators. The main goal of this study was to investigate human information processing models and workload demands on human operators, then developing a regression model for this purpose.

Material and Methods: This was a case study. Task analysis of control room members, including shift supervisor, board man, and site man and user instrumentation in this study was investigated. Data collection was performed by interviewing employees using a questionnaire with two parts the first part was the model of human information processing and the second part was workload NASA–TLX and an appendix of opinions existing staffing level and finally task analysis performed using SPSS 16 – SPSS.

Results: There was a correlation between workload and stages of human information processing model such as perception )r=0.65, p<0.01), vocal response (r=0.45, p<0.01) and manual response (r=0.15, p<0.05). Some effective factors on workload were vocal response (β=0.232, p=0.033) and perception (β=0.576, p=0.00). The most important factors in the analysis of anticipation staffing demand were perception (β=2.514, p=0.008), workload (β=1.57, p=0.018) and vocal responses (β=2.428, p=0.01), respectively.

Discussion and Conclusion: Increasing concentration and attention and perception skills using psychological measures including decreasing the workload and stress and holding specialized training courses are necessary.

Introduction: Despite the introduction and development of agricultural mechanization in the dairy farm sector of Iran, many tasks are still performed by manual labor in the country’ dairy farms, including milking, and necessitate poor body postures and movements that help increase the risk of musculoskeletal disorders among hand milking workers.

Material and Methods: The present study was conducted to assess the postural workload of workers during hand milking in the dairy farms of Ramin Agriculture and Natural Resources University and Ramhormoz county. Three milking techniques were assessed, including traditional hand milking, milking stanchion (mobile milking unit) and tandem parlor milking (the double-3 tandem). The postural workloads of 34 male milking workers were evaluated through mixed-methods.

Results: The results obtained showed that hand and stanchion milking require major parts of the body to be in a bent position over 70% of the time due to the operations taking place at a low height from the ground. In contrast, tandem milking required the body to be in a straight position over 90% of the time due to the operations taking place at a substantial height from the ground. Moreover, in terms of finger posture, all three techniques required the workers’ five fingers to be wrapped around different milking tools and parts of the cattle throughout the processes.

Conclusion: Being bent for long periods of time during the process of hand and stanchion milking and standing upright for long periods during tandem milking both caused musculoskeletal disorders of the back and backache for workers of both traditional and mechanized milking. In the case of the finger posture, prolonged repetitive finger postures decrease for milking workers with the increased mechanization of milking.

Introduction: Faculty and staff are the pillars of any university. Any impairment in the function of these elements would undoubtedly decrease the quality of education and training services provided. The present study aimed to assess the relationship between subjective workload and job satisfaction in faculty and staff members of universities of medical sciences and universities affiliated to the Ministry of Science, Research, and Technology.

Materials and Methods: This descriptive-analytical study recruited 164 faculty and staff members. Data were collected using a demographic questionnaire, NASA Task Load Index (NASA TLX), and the Job Description Index (JDI). One-way analysis of variance (ANOVA) was applied to analyze the data.

Findings: The participants’ workload had no significant effects on their job satisfaction. Faculty members generally had a heavier workload and lower level of job satisfaction compared to staff members. Moreover, faculty of universities of medical sciences had higher workload and lower levels of job satisfaction (14.5% vs. 30.76%) in comparison to faculty of universities affiliated to the Ministry of Science, Research, and Technology. Moreover, 14.5% of the medical faculty members and 30.76% of science faculty members were satisfied with their jobs. Overall, job satisfaction and workload were not significantly related with demographic characteristics and job features of the participants.

Conclusion: Among the various subscales of workload, faculty members reported high levels of subjective pressure, time pressure, and effort. Therefore, further studies are required to identify the causes of such pressures and introduce measures for their reduction or elimination.

Introduction: Advances in technology and the use of complex systems at work have imposed high mental workloads to operators; so, continuous monitoring of mental workload can help to prevent mental problems and maintain mental health. Therefore, this study aimed to investigate the impact of mental workload on physiological and subjective responses.

Methods: This cross-sectional descriptive-analytical study was performed on 16 healthy university students in 2014 at a laboratory setting. Physiological parameters of surface electromyography and electrocardiography in six blocks (resting, high mental work, moderate, low, very low and recovery) were measured using NeXus-4. After performing each block, the NASA-TLX questionnaire was completed. Statistical analysis was conducted using SPSS software version 21.0. A 5% significance level was adopted in all the tests.

Results: The results showed significant differences for the average score of NASA-TLX between the different levels of mental work load (P < 0.05). Also, the analysis of repeated measures variance showed significant differences for heart rate and heart rate variability parameters in the six blocks (P < 0.05), but no significant difference was observed for the shoulder muscles activity.

Conclusions: Different levels of mental work load can impact on people's subjective responses and some of their physiological responses. Thus, in such workplaces, it will be necessary to conduct an ergonomic program to manage mental health.

Introduction: The progress of technology and modern technology has changed today’s workplaces and imposed more mental and cognitive demands to workers. Control room is an example of these workplaces. Currently, assessment of mental workload is a key point in the research and development of human-machine relationships in workplaces. This study aimed to validate an analytical approach in evaluating demanded mental workloads for control room operators in Pars combined cycle power plant.

Methods: This was a fundamental-practical and cross-sectional study. First of all, a task analysis was used to understand the operation steps of control room operators. Then, the Visual, Auditory, Cognitive, Psychomotor (VACP) technique was applied to determine the mental workload demanded for performing each step of the works. Finally, the assigned ratings of the VACP method were validated by the analysis of Pearson’s correlation with the answers of the NASA-Task Load Index (NASA-TLX) questionnaire, collected from the control room operators.

Results: Based on the results, the correlation between the assigned ratings of VACP technique and the answers of the NASA-TLX questionnaire was positive and significant.

Conclusions: Due to the high correlation between the assigned ratings of VACP technique and the answers of the NASA-TLX questionnaire, the proposed VACP technique, which can be carried out in the early stage of the design, was suitable as an analysis tool for predicting metal workloads of control room operators.

Introduction: Work-related fatigue is a source of concern, even in most industrialized countries. One of the most important factors influencing an employee’s physical and mental condition is the degree to which employees are able to recover from fatigue and stress after work. Factors such as workload can cause fatigue in workers. The aim of this study was using the need for recovery scale to assess workload in mine workers and its relationship with demographics.

Methods: In this cross-sectional study, 80 workers of a mine were surveyed. The data gathering tools used in this study were demographic characteristics questionnaire and the need for recovery scale. The scale assesses the workers workload with 11 two-optioned phrases. Mean, standard deviation, and Pearson’s correlation coefficient and ANOVA tests were used in order for data analysis.

Results: Mean (SD) score of the need for recovery scale was 55.22 (23.93), indicating moderately high workload in the workers. A total of 58.7% of workers experienced high levels of workload. Among the demographics, only body weight had a significant relationship with the need for recovery score (P value = 0.043).

Conclusions: Due to the relatively high need for recovery in the study population, solutions should be employed, such as reducing the workload, use of work-rest schedules, performing heavy tasks within teams, and providing conditions for proper and enough recovery after work, which can increase health conditions of workers.

Introduction: Pilot performance investigation during multi-tasking operations requires a procedure, in which the parameters related to the desired scenario of the simulator are obtained in a systematic manner. The multi-attribute task battery (MATB-II) is a standard simulator of generic piloting tasks developed by national aeronautics and space administration (NASA).

Methods: Employing information theory concepts, baud rate generated in all subsystems of the MATB-II were calculated and then, a unique numerical index presenting an estimation of overall workload was extracted. In the next step, three tests with different levels of workload were conducted to examine the validity of the offered criteria. These tests were performed by a group of subjects on the role of human pilots, while recording their own experiences about perceived workload via NASA-TLX.

Results: The results confirmed that there were significant differences between averages of scores assigned by subjects to the total workload, for three levels of difficulty defined based on information theory (P-value < 0.001). This variable shows considerable growth from low to medium and from medium to high categories of workload level.

Conclusions: The proposed quantitative index is effective enough for determination of workload levels in the MATB-II simulator.

Introduction: Metro driving is one of the newest jobs in Iran. Due to the lack of studies about train drivers’ workload, there is no comprehensive information about factors that effect workload. This study aimed at analyzing the factors that may effect driver workload, in order to recommend control measures.

Methods: In this mixed method study, data generation was done through field observations, document reviews, individual interviews, focus group interviews, and focus group discussions. In order to perform field data collection, the institute for occupational ergonomics and CCD Design and Ergonomics Ltd’s developed tools were used. Directed content analysis was used for qualitative data analysis.

Results: Overall, 65 factors were extracted as the factors that may effect driver workload. The extracted factors were drawn on a fishbone diagram, over 8 categories, including management, supervision and organizational climate, infrastructure, job design, journey, and environmental as distal factors and time pressure, information exchanges, and individual factors as proximal factors.

Conclusions: Some of the distal factors are the nature of an urban transport system, so the only amendment is compensatory programs, and some of them could be resolved by long-term plans. Workload of train drivers could be reduced with a focus on the proximal factors in the short-term, and the distal factors in the long-term.

Introduction: Nurses as the most important part of human resources in the health service system are often faced with problems associated with shift work. The present study aimed to examine a mediating role of sleep quality in the relationship between workload and physical and mental health among nurses.
Methods: This cross-sectional study was conducted on 236 nurses working in three educational hospitals in Bojnord city. To collect data, the survey of shiftworkers (SOS) questionnaire was used. Data were analyzed using the structural equation modeling by AMOS-21 and SPSS 19 software packages. In addition, the Preacher and Hayes’ SPSS Macro program was used for testing mediation.
Results: The results showed that the proposed model fitted the data properly. Also, workload directly affected only physical health, and the quality of sleep had a mediator role in the relationship between workload and physical and mental health.
Conclusions: Sleep quality as an important variable can mediate the relationship between workload and physical and mental health in nurses. So, it is suggested that interventional interventions to improve the health of the staff be focused on adjusting and shifting job shifts and teaching the principles of sleep hygiene to them.
 

Background and Objectives: Musculoskeletal disorders cause about half of all work-related disease, and are the major cause of loss of time, increased costs, and labor injury. This study aims to evaluate the workload and its association with the prevalence of wrist disorders. It was carried out in the assembly workers of a manufacturing industry.
Methods: This cross-sectional study was conducted among 120 female workers employed. Theit mental workload, physical workload and prevalence of wrist MSDs were evaluated using the NASA-TLX, the OCRA method and the Nordic wrist and hand scan questionnaire respectively.
Results: The NASA-TLX showed that the physical demands and effort with mean scores of 78.79 and 78.37 were respectively the most important subjective mental workload (SMWL) scale. Also The results on the basis of the OCRA risk level showed that the highest right-hand risk was at risk level 3 and the highest left-hand risk was at risk level 1 .The Statistical analysis showed that OCRA risk levels and mean scale physical demands and efforts were significantly higher in those with wrist pain than those without pain (P<0.05).There was a direct correlation between the severity of the wrist pain with the OCRA risk index in both hands (P=0.001) and the total score of NASA (r=0.232, P<0.05).
Conclusion: It was revealed that mental load was high in assembly lines of the manufacturing industry and this result was also confirmed by physical evaluation. This study indicated that overall score of SMWL can affect the incidence of MSDs. That is why mental workload should be considered as a risk factor for MSDs.