Iranian Journal of Ergonomics
Year:2013 | Volume:1 | Issue:2|Papers Count:11

Introduction: This study aimed to determine the association between ergonomic conditions in the use of visual displays and subjective feeling of fatigue in graduate students. Materials and Methods: In this cross-sectional study, 70 graduate students were selected randomly from Hamadan University of Medical Sciences. The data collecting technique was a standard questionnaire containing 30 questions which covered the three criteria of drowsiness, inability to concentrate and physical discomfort. Ergonomic and environmental working conditions were also measured and recorded. Meanwhile, the magnetic and electric field intensities in the very low frequency range were measured according to standard methods. Then the data were analyzed using descriptive and inferential statistics.Results: The scores of indices of drowsiness, inability to concentrate, physical discomfort were 17.8 (6.5), 18.7 (4.4), 11.9 (6.9), respectively. There was a significant association between the continuous time of working with computer and fatigue (P=0.017). Significant correlation was found between the type of display used and the level of fatigue (P=0.012). However, Significant correlation was not found between environmental conditions of the workstations and feeling of fatigue (P=0.07). The difference in the intensity of magnetic fields was also significant with respect to the type of display (P=0.021).Conclusion: Inability to concentrate index had the highest fatigue score that could have a negative impact on the academic performance of students. Regarding ergonomic principles of work with computers, especially decreasing the continuous time of working with computers and using the latest visual displays can significantly reduce the level of fatigue in students.

Introduction: Considering the extent and diversity of construction activities and hazards, they are at the top ofaccident cause lists. According to the supervisor's role in safety and prevention of accidents at construction sites, this study was conducted to study the risk perception, safety attitude and safety performance in the supervisors of construction sites in Shiraz city. Materials and Methods: This descriptive cross-sectional study was achieved on 200 supervisors who agreed to participate in the study. The data collecting technique was a structured questionnaire consisting of questions regarding general information, risk perception, safety attitude and safety performance. The questionnaires were completed through self-report method.Results: All studied supervisors had medium and high risk perception (35.5 and 64.5% respectively), medium and high safety attitude (78.6 and 21.4% respectively), and medium and high safety performance (41.4 and 58.6% respectively). Among the studied variables, the size of construction site had positive and significant effect on safety performance of supervisors.Conclusion: The results of this study showed that risk perception and safety attitude are significantly associated with safety performance among supervisors in construction sites, so that by increasing safety attitude in supervisors, their safety performances were increased too.

Introduction: Noise pollution during training activities is the cause of mental fatigue, impaired concentration and learning loss in students. This study was aimed to assess noise pollution and acoustic comfort level in typical classrooms and provide corrective methods to improve conditions of acoustic comfort. Materials and Methods: In this cross-sectional study, the acoustic comfort levels were determined through a questionnaire with a reliability coefficient of 0.77 completed by 413 students in 20 classrooms in seven faculties of Hamadan University of Medical Sciences. Noise levels were measured in classrooms using a sound level meter (model TES-1358) in accordance with ANSI S12.6.Results: The mean (SD) of background and outdoor noise levels were equal to 46.97 (3) dB (A) and 57.16 (4.8) dB (A), respectively. The classroom background noise was higher than the recommended limit of 45 dB (A) (P=0.001). Construction activities were the main source of noise and impaired concentration was the most important complication of noise. The mean (SD) of signal-to-noise ratio inside the classrooms was equal to 13.14 (3.54) dB (A), which was undesirable compared with the recommended limit of 15 dB (A) (P=0.001). The difference in speech intelligibility of students at various levels of signal-to-noise ratio was significant (P=0.035).Conclusion: The results confirmed that the acoustic conditions in classrooms were not suitable. Meanwhile, the background noise level was mainly influenced by outdoor noise. Given the adverse effects of noise on the reduced concentration of the students, it is essential to take measures to improve the acoustic conditions of classes.

Introduction: The workers in Quarry and Stone Industries typically perform some tasks such as carrying and handling heavy loads frequently and for a long duration and are exposed to high risk of musculoskeletal disorders (MSDs). The aim of this study was to compare the prevalence of MSDs and the risk of work postures in workers of quarry and stone Industries. Materials and Methods: This cross-sectional and descriptive-analytical study was conducted on 63 workers of Stone Industries and 46 workers of quarries in Kermanshah. The required data were collected by Nordic standard questionnaire, Body map chart, and REBA method. The gathered data were analyzed by Independent t-test, Mann-Whitney, Spearman and Pearson tests. The significant level was considered as<0.05.Results: The most prevalent musculoskeletal disorders in both Stone and Quarry workers were related to low back and equaled to 54% and 39%, respectively. The mean (SD) of grand scores of REBA in Stone and Quarry workers were 9.06 (1.45) and 4.6 (1.18), respectively. There were significant correlations between age, work experience, and BMI with MSDs in stone workers. Moreover, significant associations were found between age and work experience with MSDs in quarry workers (p<0.05).Conclusion: The results showed that the risk level of REBA and prevalence of MSDs of stone workers were higher than quarry workers in the areas of shoulders, wrists, hands, lower back, legs, knees and ankles.

Introduction: Musculoskeletal disorders (MSDs) are the leading causes of work related injuries and disabilities in developed and developing countries. There were limited studies that have investigated the simultaneous interactive effects of individual, occupational and workplace characteristics on the development of MSDs. Materials and Methods: The data were gathered by Nordic questionnaire and Quick Exposure Check (QEC) method and were analyzed using a logistic regression model in order to study the correlation between the prevalence and severity of MSDs and individual and work-related factors.Results: Over half of the participants (61.6%) reported suffering from a particular form of MSDs during the last six months. Results showed that risk factors such as work stress, sleeping position, lifestyle, and poor posture had an important role in the prevalence and severity of MSDs. Discussion: According to the findings, the impact of a risk factor is constantly in interaction with other risk factors and is modified by various intervening factors. Participatory ergonomic intervention programs and interventions in workstations, ergo stress and life-style were suggested in order to reduce the incidence and severity of MSDs.

This before-after clinical trial investigated the effect of daylight on morning and night melatonin, subjective general health using GHQ questionnaire, sleepiness and alertness on elderly who lived in nursing houses. Nineteen nursing home residents participated voluntarily. They exposed to daylight from 9 to 10 A.M. and from 4 to 5 P.M. for 6 weeks. General health of all participants was evaluated using general health questionnaire (GHQ) as well. Also we used of KSS and VAS questionnaire foe assessment of sleepiness and alertness. Baseline morning and night melatonin levels were 25.39 (±19.75) pg/ml, and 40.3 (±21.55) pg/ml respectively. Daylight exposure significantly affected morning melatonin at 7:00 A.M. but had no significant effect on night melatonin at 8:00 P.M. Mean score of general health changed 36.31 to 29.89 (P=0.003). Karolinska sleepiness scale (KSS) and Visual Analogue Scale (VAS) showed increase sleepiness and decrease alertness from 3:00 to 7:00 A.M. Sleepiness decreased and alertness increased during 1:00 P.M and 20:00 P.M. Overall day light exposure may delay sleep phase and circadian rhythm problems in elderly people. Anxiety and insomnia could be improved with daylight exposure. Our findings suggest that elders should be exposed to scheduled daylight in morning and evening for prevention and improvement of mental disorders. Adequate light should be provided for elder’s homes and nursing house. We have proposed to further study with a larger sample size be done to assess effect of daylight on GHQ'' subscales.

Introduction: Due to the increasing complexity and competitions of organizations and job market, considering the manpower and his quality of work life are progressively becoming important. This study aimed to evaluate the quality of work life and its influencing factors in the staff of Shiraz University of Medical Sciences (SUMS). Materials and Methods: In this cross-sectional study, 218 staff ranging from 23 to 54 years of age participated voluntarily from SUMS. A questionnaire consisted of two parts was used as a data collecting tool. In the first part, demographic and occupational characteristics, and in the second part questions about the quality of work life were included. The data were analyzed using statistical tests including Pearson Correlation, Kruskal-Wallis and Mann- Whitney U by SPSS software (Version 16.0).Results: The mean (SD) score of quality of work life was equal to 127.51 (16.61). Statistical tests showed significant correlations among the score of quality of work life with the gender (p=0.013) and income level (p=0.009) of the studied subjects, so that that the quality of work life scores of women and high-income individuals were higher than those of men and lower-income staff. Furthermore, the results showed no significant correlations among age, work experience, marital status, number of children, educational level, type and the place of employment with the quality of work life scores in the studied staff.Conclusion: The study suggests that variables such as gender and the staff income level are of influencing factors on quality of work life.

Introduction: Three methods of OCRA Index, Strain Index (SI), and ACGIH HAL have been proposed for the assessment of risk factors of upper limb musculoskeletal disorders. Investigating the correlation and consistency of these three methods are of prominence importance in the workplaces. Thus, this study aimed to determine the correlations of the results of the above mentioned methods. Materials and Methods: In this cross-sectional study, a total of 150 tasks were studied in four industries. For each task, a video taping of a full working cycle was prepared and evaluated according to the instructions of each method. The level of risk exposure to musculoskeletal disorders was analyzed with correlation and Kappa agreement coefficient tests using SPSS (version 16) and R software packages.Results: The correlation between the results of risk assessments of OCRA and SI methods for right and left hands were acceptable and equal to 0.751 and 0.726, respectively (p<0.001). Meanwhile, the coefficients of agreement between OCRA and HAL methods for left and right hands were 0.526 and 0.595, respectively.Conclusion: These findings partly confirmed the agreement between the methods of risk assessment. The origin of this partial agreement can be the number and type of variables and their impacts on the final score of the methods.