Iranian Journal of Ergonomics

Introduction: Driver fatigue is one of the major causes of accidents in roads. It is suggested that driver fatigue and drowsiness accounted for more than 30% of road accidents. Therefore, it is important to use features for real-time detection of driver mental fatigue to minimize transportation fatalities. The purpose of this study was to explore the EEG alpha power variations in sleep deprived drivers on a car driving simulator.

Materials and Methods: The present descriptive-analytical study was achieved on nineteen healthy male car drivers. After taking informed written consent, the subjects were requested to stay awake 18 hrs before the experiments and refrain from caffeinated drinks or any other stimulant as well as cigarette smoking for 12 hrs prior to the experiments. The drivers sleep patterns were studied through sleep diary for one week before the experiment. The participants performed a simulated driving task in a 110 Km monotonous route at the fixed speed of 90 km/hr. The subjective self-assessment of fatigue was performed in every 10 minute interval during the driving using Karolinska Sleepiness Scale (KSS). At the same time, video recordings from the drivers face and their behaviors were achieved in lateral and front views and rated by two trained observers. Continuous EEG and EOG records were taken with 16 channels during driving. After filtering and artifact removal, power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. To analyze the data, descriptive statistics, Pearson and Spearman coefficients and paired-sample T test were employed to describe and compare the variables.

Results: The findings showed a significant increase in KSS scores in the final 10 minutes of driving (p<0.001). Similar results were obtained concerning video rating scores. Meanwhile, there was a significant increase in the absolute alpha power during the final section of driving (p=0.006).

Conclusion: Driver mental fatigue is considered as one of the major implications for road safety. This study suggests that alpha brain wave rhythm can be a good indicator for early prediction of driver fatigue.

Introduction: Musculoskeletal disorders (MSDs) represent one of the leading causes of occupational injury and disability in the developed and industrially developing countries. This study was conducted to investigate the prevalence of MSDs and evaluate the risk of these disorders among welders of a steel manufacturing industry.

Materials and Methods: This descriptive-analytical study was achieved on all 243 welders employed in a steel manufacturing industry. Nordic Musculoskeletal Questionnaire (NMQ) was used to study the prevalence of MSDs. Meanwhile, QEC technique was employed to evaluate the risk of exposure to these disorders. For data analysis, central statistical indices, T-test and Chi-square test were used.

Results: The results suggested the highest prevalence of symptoms of musculoskeletal disorders in low back, trunk and knees, respectively. QEC technique showed a high and very high risk of exposure to MSDs in 64.6 % of welders.

Introduction: Academic achievement is one of the main objectives of educational programs and the most important concern of education administrators and families. The education administrators' emphasis on courses other than physical education as a means for the students to get better overall scores results in a general neglect toward physical education or its elimination from curricula due to reasons such as shortage of funds. Physical activity is claimed to affect the structure of the brain and improve memory function and ultimately lead to academic achievement. The purpose of the present review study is to examine the current evidence on the relationship between aerobic fitness and academic achievement.

Materials and Methods: Different articles and papers were accessed through databases and search engines such as ‎Google Scholar‎, PubMed and Elsevier and using keywords such as “academic achievement”, “aerobic fitness” and “memory”. The articles used were published between 1998 and 2014.

Findings: The hippocampus function is an important factor in the consolidation of short-term and long-term memory and is severely affected by neurotransmitters and hormones. Physical activities at an intensity higher than average have a strong effect on the release and regulation of hormones and neurotransmitters and thus improve the memory function indirectly. Studies have shown that physical activity has a positive effect on scores obtained in different courses, particularly in mathematics, through increasing the aerobic capacity.

Conclusion: The aerobic fitness following regular physical activity not only leads to general health and reduces the risk factors of health and the incidence of diseases, but also improves the memory function and ultimately leads to academic achievement through affecting the brain structure physical education courses should therefore be more emphasized at schools.

Introduction: Physical activity has been identified as a potential intervention to improve body composition in women with breast cancer. This research sought to investigate the effects of an eight-week aerobic training program on some anthropometric indices and cardiorespiratory fitness of middle-aged women with breast cancer.

Material and Methods: A total of 15 women with breast cancer (age: 40-60 years) were selected through convenience sampling. They attended an eight-week aerobic exercise program consisting of three 40-60-minute sessions per week. Exercise intensity was maintained at 30%-60% the subjects’ heart rate reserve (HRR). The participants’ weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist to hip ratio, waist to height ratio (WHR), body fat percentage (BFP), and maximum oxygen consumption were measured at baseline and after eight weeks of exercise. Data were analyzed by paired samples t-tests at a significance level of 0.05.

Results: Significant reductions in the patients’ weight (P = 0.001), BMI (P = 0.001), WC (P = 0.006), HC (P = 0.001), WHR (P = 0.006), and PBF (P = 0.001) were observed after eight weeks of aerobic training. Moreover, exercise significantly increased the subjects’ maximum oxygen consumption (P = 0.008). However, changes in the participants’ waist to hip ratio were not significant (P = 0.235).

Conclusion: According to the obtained results, an eight-week aerobic training program could significantly improve some anthropometric indices and cardiorespiratory fitness in women with breast cancer.

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: The silence of employees has become a critical issue for organizational development, referring to deliberate neglect of important ideas, suggestions and opinions about their work. The purpose of this study was to investigate the impact of variable organizational support perceived by employees on breaking the silence with the mediating role of emotional commitment.
Methods: The statistical population includes 900 governmental employees from which 273 persons have been selected using Cochran formula and random sampling method. Information gathering tools include Eizenberger (1986) perceived organizational support questionnaires, Allen & Meyer (1990) affective commitment Questionnaire and Silence climate questionnaire of Vakola and Bouradas (2005). After gathering requested information from the participants, the information was analyzed by Microsoft Excel 2016, SPSS 23.0 and smartpls3.
Results: The results showed that perceived organizational support was positively correlated with employee silence. The results also showed that the emotional commitment mediates the relationship between perceived organizational support and employee silence.
Conclusion: Given the relationship between perceived organizational support and emotional commitment with employee silence, it is essential for planners to consider these components.

Background and Aim: Job adjustment is an important factor for the successful employment of nurses. The job nature can be a factor influencing job adjustment. The aim of the present study was to investigate the effect of job nature on job adjustment among a sample of nurses. 
Methods: This cross-sectional study was conducted among 542 nurses working in hospitals affiliated to Kashan University of Medical Sciences. Using Cochran's formula and stratified random sampling method, 190 nurses were selected as a sample. Two standard and validated questionnaires were used for gathering data associated with job nature and job adjustment. The reliability of the questionnaires was estimated through Cronbach's alpha coefficient. Data analysis was performed at both descriptive and inferential levels using SPSS 22.
Results: Findings revealed that means of job nature (70.43±45.07) was higher than average (60) and mean of job adjustment (3.23±0.42) was higher than average (3). Pearson correlation coefficient showed that there is a positive and significant relationship between job nature and job adjustment (r=0.29). The regression coefficient showed that the job nature was able to predict the job adjustment of nurses.
Conclusion: The average job nature and adjustment of nurses were favorable and there was a positive relationship between job nature and job adjustment of nurses. Therefore, in order to increase the adjustment of nurses, managers should pay more attention to nurses' perceptions of their job characteristics and provide them with diversity, feedback and the opportunity to create friendly relationships at work.