Iranian Journal of Ergonomics

Background and Objectives: Quality of work life is one of the most important factors in promotion of teachers and having them continue their jobs. This study aimed at designing and evaluating a questionnaire for teachers’ work life quality. 
Methods: In this research, a sequential exploratory approach (instrument editing model) was used and in the qualitative stage, a semi-structured interview method was used to determine the quality of life of teachers. In the qualitative stage, indices of work life quality were identified using semi-structured interviews with 12 teachers (9 men and 3 women) of Karaj city (2014-2015 educational year) selected through purposive sampling method. The qualitative data was analyzed using Straus and Corbin method. Subsequently, a questionnaire of teachers’ working life quality was constructed based on these indices and was validiated in the quantitative stage.
Results: Content validity was confirmed by five experts using content validity index. A sample of 760 (387women) teachers selected through multistage cluster sampling were handed out two questionnaires including a researcher-made questionnaire of teachers quality of working life and Walton (1973) quality of work life questionnaire. Construct validity of the research-made questionnaire was examined using exploratory factor analysis. Eight factors were extracted and confirmed through confirmatory factor analysis. Fit indices of model indicate compliance. Convergent validity was confirmed by its correlation with the quality of work life questionnaire (P<0.01). Reliability was confirmed by calculating Cronbach’s alpha coefficient (0/74-0/88).
Conclusion: The results of the study indicated that the researcher-made questionnaire with regard to its design in the job context of Iranian teachers, with 54 items, is an appropriate tool for assessing the quality of their working life.
 

Background and Objectives: The progress and rebound of organizations depends on their productivity. Many factors affect the organization’s productivity; identifying these factors the organization’s deterrence can be prevented. In this study, the relationship between job burnout and employee productivity has been investigated.  
Methods: This research is applied and its statistical population is 1265 people in Shariati and Kharazi hospitals. 294 of these employees were selected by Convenience sampling method considering the Cochran formula. Data was collected using the Maslach Burnout Standard Questionnaire and Hersey and Goldsmith Human Resources productivity Standard Questionnaire. Pearson correlation test and SPSS18 was used to analyze the data.
Results: The results of data analysis showed that burnout, emotional exhaustion, depersonalization and reduced personal accomplishment with -0.82, -0.86, -0.83 and -0.85 correlation values, respectively, have a reverse and meaningful relationship with employee productivity of Shariati and kharazmi Hospitals employees.
Conclusion: Since the results showed that burnout and its dimensions have a significant relationship with productivity of Shariati and Kharazmi Hospitals in Isfahan, it is necessary for organizations to apply measures to reduce the feeling of burnout in the staff. The results of this study are consistent with the results of other studies. At the end of the study, were presented several research proposals based on the results of the study.

Background and Objectives: The use of new technologies, particularly mobile phones, is drastically growing on a daily basis. The usability of mobile phones can be determined for different age groups in order to reach a balanced development plan with respect to this technology. The present study aimed to investigate and compare the usability of touch-screen and button cell phones among Iranian elderly users, with respect to objective performance and perceived usability.  
Methods: In this cross-sectional study, 20 elders (50% female) with an average age of  were selected by simple random sampling method to measure the usability of touch-screen and button cell phones. In order to assess the objective performance of how elders work with cell phones, tests were conducted including items like typing speed, number of typing errors, taking photo, creating new contacts, and sending text messages. Perceived usability was obtained using a questionnaire of cell phone usability. Furthermore, muscle pressure and mental work load during cell phone use were evaluated by Borg CR10 and NASA-TLX questionnaires, respectively. Data were analyzed conducting statistical analysis tests of T-test and Mann-Whitney by SPSS24 software.
Results: Results revealed that the average typing speed and typing errors in touch-screen cell phones are larger than that in button cell phones. Moreover, the average of perceived usability in touch-screen cell phones (5.8) is higher than that in button cell phones (4.3). Pearson correlation coefficient showed an inverse relationship (-0.3) between perceived usability and mental work load obtained in both types of the cell phones. Findings showed that the maximum perceived muscle pressure when working with a cell phone is felt in the neck area. 
Conclusion: According to the obtained results, touch-screen cellphones are suggested for those elders who type more and button cell phones are recommended for those who use the cell phone menu more frequently, namely taking photo, calling, internet, and so forth.
 

Background and Objectives: Considering that musculoskeletal disorders and occupational stress are one of the most important reasons for disability, physical and mental problems in the staff, the study of their causes is of great importance. Therefore, this study was conducted to investigate the relationship between ergonomic risk level and job stress in employees of a food production plant. 
Methods: This was a descriptive-analytic research. It was carried out for a sample of 200 employees in the production and packaging of a food production plant in 2018. The QEC method was used to determine the ergonomic risk level and the OSPU questionnaire was used to measure occupational stress. Descriptive and inferential statistics (T and F tests) were used to analyze the data. 
Results: The findings showed that the level of ergonomic risk in the neck, shoulders and wrists is in the unfavorable situation. Workstations will need to be repaired in the near future. There is a significant relationship between the level of ergonomic risk and the demographic variables of gender and education with job stress.  
Conclusion: Unfavorable ergonomic status of workstations in the food factory has increased the worker’s stress in the manufacturing and packaging sectors. Therefore, proper design of workstations and consideration of ergonomic principles are effective in improving the physical and mental health of employees. 
 

Background and Objectives: Studies have shown the effect of smoking on mental and cognitive performance of the individuals who need to concentrate on their work. The present study aimed to investigate the effect of smoking on cognitive performance of the automotive industry workers. 
Methods: In this case-control study conducted in 2018, 280 automotive industry workers were selected through the simple random sampling and then assigned to  two groups of smokers (100 cases) and non-smokers (180 controls). All the subjects were selected from the environments with the sound levels of 82 to 88 dB. The workers’ cognitive performance was also tested using the CPT, Stroop and Tower of London tests.
Results: The mean age of the case group was 36/02 (3/7) and that of the control group was 36/25 (3/65) years. The results showed that the scores of the TOL test in the case group (smokers) were lower than those of the non-smokers (OR=0/903, P<0.01), and other items of the TOL test had no significant relationship with the individuals’ smoking status (P>0/05). The Stroop and continuous performance tests also had a significant relationship with the individuals’ smoking status in terms of the number of correct responses and the response time as well as interference (P<0.01). Other items had no relationship with the individuals’ smoking status (P>0/05).
Conclusion: The results of this study showed that the use of cigarettes and nicotine substances significantly decreased the workers’ mental and intellectual performance, and smokers were more likely to suffer from concentration interference, low brain processing speed in decision-making, and low precision at work, compared to non-smokers.
 

Background and Objectives: Noise pollution is one of the most harmful physical factors in working environments in developed and developing countries, which has significant impacts on the workers’ quality of life. The aim of this study was to investigate mental and physiological effects of chronic exposure to noise.
Methods: This is a cross-sectional study carried out randomly in 2018 on 250 workers in the automotive Industry. To measure the subjects’ aggression and annoyance levels, the Buss and Perry’s Aggression Questionnaire was used as well as an annoyance questionnaire. In this study, blood pressure measurement was also done using ALPK2 mercuric pressure gauge.
Results: The results showed that there was a significant difference in the systolic and diastolic blood pressure and noise annoyance in the groups with a lower-than-85 and higher-than-85 dB sound pressure levels (P<0.001). Besides, the results of multivariate regression showed that the annoyance level and sound pressure level had a significant relationship with the workers’ blood pressure (P<0.01). Also, there was a significant correlation between aggression components and sound pressure level (P<0.01).
Conclusion: The results of this study clearly showed that chronic exposure to noise in work environments was associated with psychological and physiological changes, such as increased blood pressure and aggression levels. Hence, implementation of preventive programs can help reduce the incidence of the psychological and physiological disorders.
 

Background and Objectives: There are various models of socket wrench in the market varying in the length and diameter of handle and weight. Each of these features alone can modify the force applied by the hand and affect how comfortable the user is. The purpose of this study was to investigate the relationship between dimensional properties and weight of several models of socket wrench with their usability index score.  
Methods: 58 male technicians from maintenance units of Shahid Beheshti University of Medical Sciences performed the task of opening 12 bolts with 8 N/m of torque using 6 models of socket wrench with different physical properties. The sample size was selected based on proposed figures for usability studies.  The System Usability Index (SUS) validated questionnaire was used to determine the usability score of each model after the experiment. The study was conducted in 2017. SPSS 21 was used for data analysis.
Results: The results showed that there was a significant relationship between usability index score and dimensional properties and weight of wrenches (P<0.001). Wrench models with longer handle and diameter size close to optimum range of diameter of hand tools for male users had a higher usability score, and participants reported a better test experience with these models.
Conclusion: Using the System Usability Index (SUS Questionnaire) to measure the quality of human-centered design of hand tools is a good way to evaluate and select the hand tools that are widely used by technical staff. The results of this study are valid for short-term applications of wrenches. However, for long time activities, epidemiological and physiological evidences such as EMG should also be used.

Background and Objectives: Mental fatigue is a condition triggered by prolonged cognitive activity. Mental fatigue causes brain over-activity. This is a condition where the brain cells become exhausted, hampering person productivity, and overall cognitive function. The aim of this study was to assess students’ mental fatigue using brain indices.
Methods: The present descriptive - analytic study has been conducted on 20 students of the Faculty of Health mean age (SD) of 24.40 (3.73) years old in Ahwaz University of Medical Sciences (2019). To assess the performance of the participants, they were asked to study a text with spelling errors and correct those errors. This activity was performed in five stages, each lasting 15 min and EEG was recorded at all stages, and at each stage, the visual analog scale was completed by participants. Data analysis was done by SPSS 24.
Results: The results showed that the activity of alpha, beta, and theta signals in the first 15 minutes was 0.89±0.30, 0.70±0.33, and 1.19±0.36, and the last 15 minutes, 0.63±0.34, 0.55±0.26, and 1.03±0.34 respectively. Reducing the activity of the signals indicated there has been an increase in the amount of mental fatigue in individuals. Also, using visual analog scale, the individuals have acknowledged that they have experienced symptoms of mental fatigue. Finally, there was no significant relationship between students’ EEG and visual analog scale.
Conclusion: The results showed that alpha, beta and theta indices could be suitable indicators for evaluating mental fatigue. Also, mental fatigue can be one of the factors that affect the accuracy and performance of individuals, so that it can reduce their attention and efficiency.

Background and Objectives: The ethic-based culture is the predictor of ethical behavior and organizational citizenship behavior. Ethical culture enhances our awareness of our activities and can also increase our awareness of our bilateral commitments to the organization and therefore focus on what is important in an organizational setting. The present research aimed at investigating the relationship between the ethical culture with a tendency to ethical behavior and organizational citizenship behavior by examining the mediating role of the person’s organization in the staff of Urmia University.
Methods: This descriptive correlation study is a structural equation modeling model. The statistical population of this study consisted of all 503 high school graduates of Urmia University in 2018. Based on the stratified random sampling method, 217 individuals were selected. Standard questionnaires were used to collect information. Data analysis was performed using descriptive indexes and structural equation modeling method.
Results: Based on the results there is a positive and significant relationship between ethical culture with ethical behavior and organizational citizenship behavior. Also, the direct and significant impact of ethical culture on the individual-organizational adaptability was confirmed. The results also showed that the individual-organizational adaptability has a positive and significant relationship with ethical and organizational citizenship behaviors. In addition, the role of mediation of this variable (individual-organizational adaptability) in the relation between the ethical culture with two other variables (ethical and organizational citizenship behaviors) was also confirmed based on the findings of the research.
Conclusion: Based on the findings, it can be concluded that ethical culture directly promotes personal-organizational fit. In addition, confirming the mediating role of the individual-organization fit ethical culture has an indirect, positive and significant effect on ethical behavior and organizational citizenship behavior.

Background and Objectives: Given the increasing prevalence of smart phone usage, it can be considered as an important and significant issue in all aspects of human life. Therefore, the purpose of this study was to study the effect of duration of smartphone use on head and shoulders’ posture of young adults aged 20-35 years.
Methods: The statistical population of this study was young people aged 20 to 35 with smart phones who were resident of Kish Island in 2018. A sample of 50 people (25 men and 25 women) were selected voluntarily and purposefully. Low- user and High- user groups were identified by completing the form of addiction to smart cell phone, in assessing the status of upper limb, the shoulder position was measured by Scapular index and head position was measured by photogrammetric method technique and Kinovea software. Independent t-test was used for comparison of experimental variables between two groups. Data were analyzed with SPSS  22. P<0.05 was considered significant.
Results: The findings showed that there is a significant difference between upper limb posture in Low- user and High- user groups (P=0.033). There was also a significant difference in shoulder position between men and women (P=0.002). But regarding head positioning, there was no significant difference between men and women (P=0.436).
Conclusion: Thus, it seems that considering the significant difference between the two groups mentioned for upper limb posture, we can use the results of this study to inform, prevent and improve the upper.

Background and Objectives: In recent years, due to the rapid growth of metropolitan cities and the shortage of urban public transport means, including urban bus transportation, many people are forced to travel in a standing position when using these vehicles. This situation may cause pain and discomfort and non-collision injuries for passengers. The purpose of this study was ergonomic assessment of the sit-standing seat in passengers standing on urban buses.
Methods: To do this study, 8 young people with a mean age of 25.25±2.12 years were enrolled. For evaluation and assessing the effect of sit-standing seat two methods of surface Electromyography (sEMG) and Borg scale scores were applied in Fall 2018. The data was analyzed using SPSS 24.
Results: In all body parts, except for the hip, the mean scoring of Borg’s scale for perceived discomfort in sit-standing position was less than standing position. Also, the amount of contractile activity of the leg muscles in sit-standing position was significantly lower than the standing position (P<0.05).
Conclusion: Considering the results obtained from the Borg scale scores and the contraction activity of the leg muscles as a result of the use of the mentioned seat, which led to a reduction in the level of discomfort and the leg muscles contraction, it is recommended to apply the sit-stand seat instead of being in a standing position.

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.

Background and Objectives: Human errors in dialysis care can cause injury and death. One of the basic steps to increase reliability in this critical process is to analyze the error and identify the weaknesses of doing this process.
Methods: The present study is a descriptive-analytic cross-sectional study. The SPAR-H method was used to identify and evaluate the probability of human error in the dialysis process. The hospital had six dialysis department and 16 dialysis machines with two nurses in each department. Data collection was done by observing the dialysis process, interview with nurses, reviewing the documents, methods of work and work instructions.
Results: The present study showed that the probability of human error in the duties of a dialysis nurse is in the range of 0.02-0.44 (except for devices related to disorder), which is related to sub-duty preparing patient as lowest rate and sub-duty of the pump set-off as highest error rate.
Conclusion: To reduce and control the human error in nursing duties in the dialysis department, control measures should be done such as increasing the number of personnel, changing the time shift of nurses, and training, preparing and revising the instructions.

Background and Objectives: The statics and actions of people during daily activities plays a major role in the physical and mental health and dynamics of the community. Given that humans deal with different things in a day, it is necessary that they are adapted to his features of body. The main goal of this study is to design and construct tables and ergonomic chairs for cartography, in accordance with the physical dimensions of students.
Methods: In this research, one of the most used educational furniture, namely cartographic table and chairs, has been studied. After examining the satisfaction of this furniture, for ergonomic review and design in accordance with anthropometric dimensions, physical features of 160 students of art and 40 students of a technical and vocational school were measured. Then data was analyzed by SPSS 18 software.
Results: According to the results, about 70 percent of the students did not feel comfortable with the features of former chair and table, except for the length of the thigh. There was no significant difference between the different educational foundations in the vocational schools and finally, with the help of tonality features, the drawing table and chair were designed which except for the height of the sitting space, in other indices, there was a 100% correlation with the dimensions of the student's body.
Conclusion: In this study, there was a lot of dissatisfaction among students due to the lack of matching these educational materials with their physical dimensions which has caused physical, mental and psychological damage and poor quality of education. At the end of the study, through ergonomic design, matters of satisfaction, sustainability and reduced production costs and also the reasons for students' dissatisfaction with the drawing table and chairs is presented.

Background and Objectives: Most accidents are caused by unsafe behaviors or human errors. Safety experts have argued that with the increasing focus on human behavior, it can significantly reduce accidents. The aim of the present study was to examine neuroticism, safety efficacy and regulatory focus as predictors of unsafe work behavior of employee Bidboland Gas Refining Company.
Methods: The statistical population of the study consisted of all employees of operational and staffing departments of Bidboland Gas Refining Company in Khuzestan. The sample consisted of 273 employees who were selected using stratified random sampling. At first, the participants were divided into two groups, safe employees and unsafe employees by using Safety Behavior Scale (Salleh, 2010). Then to evaluate the variables studied, NEO personality characteristics (Costa & McCrae, 1992), safety efficacy (Brown, et al., 2000) and regulatory focus at work (Wallace & Chen, 2006) questionnaires were used. Data were analyzed through discriminant analysis and using SPSS 16 software.
Results: According to the results, unsafe behavior of employees can be predicted from neuroticism, safety efficacy and regulatory focus and its dimensions (prevention focus and promotion focus).
Conclusion: Neuroticism increases unsafe behaviors and safety efficacy and regulatory focus (prevention focus and promotion focus) decrease unsafe behaviors of employees.

Background and Objectives: Playgrounds play a very important role in the development of children's communities and their physical skills. If these spaces are designed according to safety standards, they can contribute to the better social and physical growth of children. The purpose of this study was to evaluate the safety status of children's playground equipment in Hamadan Luna Park according to the standards of the U.S. Consumer product safety commission (CPSC).
Methods: The present study was a descriptive and analytical one. The statistical population included a total of 600 persons, working in one of the regions in the Tehran Municipality. Of the 600 staff, a total of 255 were selected as the available sample group. The instruments consisted of the questionnaires, including the individual and occupational information, the Nordic questionnaire, the Walton Quality of work life, and the checklist of the ergonomic indices of the working environment for the administrative staff. In order to analyze the data, Student’s t-test and multiple regression analysis were used.
Results: The results showed that among the main playground equipments, the spiral slide has the highest ratio of 76.1% and the seesaws with 25% minimum compliance with the CPSC standard. Among the most commonly problems in this field the non-standard design of play equipment, incorrect assembly, installation and placement in use zones can be pointed.
Conclusion: According to this paper’s report, given the undeniable role of the safety of playground equipment in preventing possible harm to children, they must be secured and adapted to global standards.

Background and Objectives: Musculoskeletal disorders are common in students and several causes may be considered for them. The aim of this study was to investigate the relationship between school furniture dimensions and trunk posture with musculoskeletal disorders in students of the sixth grade of elementary school in Karaj.
Methods: In this cross-sectional study, 346 boy students in sixth grade of elementary school in Karaj were selected. A flexible ruler was used to measure thoracic kyphosis and lumbar lordosis angles. A 50-centimeter metal ruler was used to record ergonomic and anthropometric data of the students. Spearman’s correlation test was run to analyze the collected data at the significant level of 0.05.
Results: The results showed that only 18%, 12% and 50% of desk height, seat depth and seat height measures were at normal ergonomic conditions, respectively. A negative significant correlation was observed between seat depth and total Nordic score (P<0.05).
Conclusion: It seems that school furniture dimensions in sixth grade boy students of elementary school in Karaj were not in acceptable condition. So, we suggest that ergonomics standardization of school furniture should be considered to prevent its possible consequences.

Background and Objectivse: The employees of an industrial sector, especially the food industry, tackle many problems due to their type of job. Among these staff, non-standard working postures is known as a risk factor for musculoskeletal disorders. Musculoskeletal disorders affect the function and self-efficacy of these people and ultimately leads to a reduction in their performance. Therefore, in this case, research entitled: Study of risk factors of the ergonomic work environment and its relation with self-efficacy and job performance of employees of the food industry has been done.
Methods: A total of 202 people were selected as the sample group using a random sampling method. Then they completed the research questionnaires. The research tools consisted of Paterson's job performance questionnaire, Scherer general self-efficacy, Key Indicator method and a five-point body map questionnaire for assessing body organs discomfort and prevalence. Data was analyzed using SPSS 19.
Results: There was a significant difference between the level of risk of musculoskeletal disorders and their job performance and between the risk of musculoskeletal disorders and the prevalence of musculoskeletal disorders. The lower back showed the highest prevalence of musculoskeletal disorders. There was a significant difference between the levels of risk of musculoskeletal disorders with job performance and also between musculoskeletal disorders with job performance and self-efficacy. The results showed a positive and significant relationship between job performance and self-efficacy.
Conclusion: The results indicated the role of self-efficacy in preventing behaviors that lead to exacerbation of musculoskeletal disorders. This will ultimately be reflected in their job performance and both the individual and the organization concerned. Also, employing high self-efficacy staff can improve work performance and productivity and contribute to better production processes.

Background and Objectives: Recognition and prevention of burnout plays an important role in promoting mental health and increasing the quality of services provided. This paper aimed to prevent the occurrence of this problem, seeking to identify the effective factors on the employees' burnout.
Methods: Many studies have been carried out by researchers on staff burnout using a descriptive-analytical approach, but there is no model comprehensively identifying the factors affecting employee burnout and, more importantly, expressing the relationships between the factors involved. Therefore, system dynamics analysis and VENSIM software have been used for explaining the quantitative relationships between factors affecting employees' burnout, evaluation and simulation.
Results: After designing causal, flow diagrams and model validation, four scenarios were extracted using system dynamics and simulation methods. The first scenario, which shows the current status of the company, indicated an increase in burnout. In the second scenario, with increased job satisfaction, employee productivity increased, but higher productivity, in practice, did not lead to reduction in burnout. In the third scenario, burnout decreased with increasing occupational control variables. And in the fourth scenario, by increasing the welfare and rest parameters of the staff, it was found that this scenario also had a significant effect on reducing the burnout of employees.
Conclusion: From among the four simulated scenarios, the fourth one, which is the increase in staff welfare parameters, had the most impact on reducing the burnout of Ardabil Regional Water Company employees.

Background and Objectives: Bank staff do much of their work using computers, Their equipment and layout may put the body in an inappropriate position and lead to musculoskeletal disorders (MSDs), so this study aimed to determine the prevalence of MSDs in bank staff and its relationship with office tensions.
Methods: This descriptive cross-sectional study was performed on 173 employees of Melli Bank of North Khorasan Province. The prevalence of MSDs was estimated through CMDQ, Risk factors were estimated through ROSA and data were entered into SPSS 20. Then their relationship with each other and with the equipment layout was determined by Spearman test.
Results: The mean ROSA scores were 4.73±0.793 and 63.6% of the postures were in the intervention group. The mean CMDQ scores were 103.63±181.004. Spearman test showed a good correlation between ROSA and CMDQ results (P=0.021, R= 0.175). There was a significant relationship between work experience and prevalence of MSDs (P=0.037, R=0.159). Kruskal-Wallis test showed a significant relationship between education level and CMDQ scores (P=0.38). The most common disorders in the organs were neck (53.8%) and lower back (49.7%).
Conclusion: Given the correlation between the ROSA results and the CMDQ, they can be used together. The change should be considered immediately for persons who are in intervention group. The chair and monitor played a more important role in raising the ROSA score. Improvements should be made by providing an ergonomic chair as well as a proper layout of other equipment such as a monitor.