مجله ارگونومی
سال یازدهم شماره 2 (تابستان 1402)

Back ground and object: 

In today's advanced world, one of the most serious problems is musculoskeletal problems. The purpose of this research is to investigate the relationship between ergonomics and postural abnormalities in manufacturing workers.

 The statistical population of this research consists of male employees working in a two production units  with a total number of 210 people. 134 people were included in the study according to Morgan's table and based on the entry criteria. The assessment of pain in different parts of the body was done by the Nordic questionnaire, the ergonomics of the work environment was evaluated by the REBA scale, and the body posture was evaluated by the New York test. After collecting various data, SPSS software version 26 was used to analyze the data. To check the normality of the data distribution of each variable, the Shapiro-Wilk test was used. Also, linear regression statistical test was used to check the relationship between research variables. The significance level throughout the research is less than 0.05.

The result of the research showed that there is a significant and negative relationship between the ergonomic score and the assessment of physical condition (P=0.00, R=0.79). Also, the results of the investigations show the existence of musculoskeletal disorders in different areas of the body with the highest prevalence in the back (45.7%).

According to the high and negative correlation of the variables, it was found that the unfavorable ergonomic condition can lead to poor physical condition and have many musculoskeletal consequences.

 The purpose of this study is to investigate the effectiveness of cooling vests based on nanofibers and packages of phase change materials (PCM) in reducing the thermal stress of medical personnel in hot work environments.

In this experimental study, 20 males were exposed to 10 combined scenarios of temperatures of 24 and 32 degrees Celsius and five samples of vests made with hot air temperature conditions in a room simulating atmospheric conditions. Physiological parameters including skin surface temperature, tympanic temperature and oral temperature were measured before and after exposure to air temperature conditions by simulating the activity metabolism of hospital workers. The normal distribution of the data was done with the Kolmogorov-Smirnov test and the analysis of the effect of the scenarios was done through the analysis of variance with repeated measurements.

The results confirmed that in the condition without a vest, the air temperature of 32 °C compared to the air temperature of 24 °C had a greater effect in increasing the tympanic body temperature (p<0.05). The significant effect of using Nano fiber vest along with the use of packages containing phase change materials (PCM) with effect size of 0.498, 0.568, 0.349 respectively in reducing skin temperature, tympanic temperature and oral temperature in conditions of warm temperature was observed(p<0.05). The size of the effect of increasing the air temperature was lower than the size of the effect of the type of cooling vests on the physiological responses and it indicated that the effectiveness of the designed vests increases with increasing temperature (p<0.05).

 The use of Nano fiber cooling vests and packages of phase change materials (PCM) is effective in maintaining the body temperature stability of medical personnel in hot environments due to acceptable weight and acceptable effect size.

Today, the employees have moved towards less mobility and more sitting due to the use of modern technologies in the workplace, and the complications arisen from static work and fixed posture have caused numerous disorders, including musculoskeletal disorders. This study was conducted in order to evaluate the comfort and usability of the ergonomic sit-stand desk converter with the purpose of prevention of disorders caused by continues sitting in workers.

30 employees and Faculty Members of a university voluntarily entered this study with consent and awareness. After providing the necessary explanations, two researcher-made questionnaires of Local Perceived Discomfort (LPD) and Sit-Stand Desk Converter Usability Questionnaire (SSDCUQ), two methods of posture analysis, two methods of Workstation evaluation and general satisfaction together with 2-8-20 software and an ergonomic desk converter were provided to the volunteers. After the test period, SPSS version 22 software and statistical tests such as mean, standard deviation, Spearman's rank correlation coefficient, and Pearson correlation coefficient were used to analyze the data.  

The total average of LPD in different parts of body was 0.48 ± 0.87, which indicates that the converter works in the range of no problem to very little discomfort. The average general satisfaction with the converter's function was 3.18 ± 1.08 which is in the moderate to good range. Also, a significant relationship was found between different situations of using the converter in the analysis of different sitting and standing postures (P<0.0005), which indicates the improvement of the sitting and standing posture during the use of the converter.

height-adjustable workstations are a good choice to reduce sitting time and improve posture. Despite the improvement of sitting and standing posture when using the converter, there are limitations such as the user ignoring software warning to sit and stand in the mechanical converter under study

Psychological load such as workload not only disrupts work performance, but can also have a direct effect on employee safety through accidents. However, despite this issue, many efforts have not been made to develop an assessment tool to measure psychological burden related to occupational safety and health of employees. Therefore, the present study was designed with the aim of validating the psychological burden scale of workers by Kim et al. (2018) from the perspective of occupational health and safety. 

The statistical population of the research consists of all the workers working in the Eastern Alborz Company of Shahroud city, and 349 workers participated in the research using a simple random sampling method. In the present study, the mental load scale of Kim et al. (2018), the Copenhagen psychosocial scale (COPSOQ) and the occupational stress scale (HSE) were used. The data were analyzed using Pearson's correlation coefficient tests and confirmatory factor analysis using SPSS-22 statistical software and Lisrel version 8.5.

Resalts: 

The results showed that all the components of workers' psychological burden with the overall score and Psycho-social scale and occupational stress scale have a positive and significant relationship. The results of the confirmatory factor analysis also showed the good fit of the model in determining the factors in the initial form expressed by Kim et al. (2018). To determine the reliability of the scale, the value of Pearson's correlation coefficient was obtained at 0.82 in the test and retest phases. Also, the results of this study showed that 26.1 percent of workers experience low psychological burden, 49.6 percent of workers experience moderate psychological burden, and 24.4 percent experience severe psychological burden.

Based on the results of the current research, the workers' mental burden scale (Kim et al., 2018) is a valid and reliable scale and can be used to evaluate the psychological burden of workers in research and intervention studies.

In work environments, job stress is the main factor that can break the control of employees and provide the context for the occurrence of aggression in employees. For this reason, this study investigated the role of the effort-reward imbalance model in the occurrence of bullying in the workplace.

This study was descriptive-analytical in nature. In this research, to measure the variables, two self-report questionnaires, the effort-reward imbalance scale and the negative actions questionnaire, were used.  The research population was employees of one of the process industries, and 202 people were included in the study using the census method. Analyses were performed using SPSS 18 software, Pearson’s correlation coefficient, and linear regression.

 The total number of participants in the study was 202. The average age and work experience of the participants in this study were 40.13±9.32 and 15.9±9.50 years, respectively. Among the participants, 72.8% were male and 86.1% were married. In terms of educational status, 10.9% had an associate's degree, 81.2% had a bachelor's degree, and the rest had a master's degree or higher. About three-fourths of the people were officially employed, and the rest were working on a contract basis. Based on the results of the multivariate regression model, among the variables investigated in this study, effort-reward imbalance and extreme commitment were able to significantly predict the changes in the bullying score (P<0.001).

Employees who feel imbalanced between inputs and outputs in the job, as well as employees who have the characteristic of extreme commitment, are more likely to engage in negative behaviors in the form of bullying in the workplace.

There is no consensus for transforming the origin of scoring on the Likert’s scale in a questionnaire. This study was carried out with the aim of investigating the effect of the transformation of the origin of scoring on the indices of central tendency, dispersion and the independent t-test.

In the study, the effect of transforming the origin of scoring was investigated inferentially, and the results of the transformation were compared by a illustrating. In this research, a 4-point Likert’s scale was considered starting with scoring zero and one. Independent t-test was used to compare the mean scores in two groups.

The results of the study showed that transforming of the origin of scoring from 1 to zero in the Likert’s scale only leads to a difference in the value of the tendency to the center. While the dispersion indices and statistical statistics will not have any difference in both scoring methods.

Changing the origin of scoring in the questionnaires when the total scores have a normal distribution, does not affect on the independent t-test and standard deviation, and only the indices of the tendency to the center will be different in the two scoring systems.

 Musculoskeletal abnormalities are still an important problem in many workplaces and health care center employees. The purpose of this systematic review is to investigate musculoskeletal abnormalities and occupational risk factors among medical staff in Iran.

 In this systematic review of eligible studies from national and international databases including PubMed, Embase, Web of Science, Scopus, SID, Magiran and IranMedex from 1390 to 1400 based on the preferred reporting cases of the Guidelines for Systematic Reviews and Meta-Analysis (PRISMA) as It was independently extracted by two researchers. MeSH keywords and phrases were used to implement the search strategy.

 Among 360 articles, the full text of 24 articles was finally examined. The results of the study showed that the highest prevalence of musculoskeletal abnormalities and employee complaints in the last 12 months is related to neck pain (46.01%). Also, among the 24 identified occupational risk factors, standing for a long time (20.83%) and repetitive movements (16.66%) are the most important factors in the occurrence of physical disorders in the treatment staff.

 The findings of this research can play a significant role in empowering and upgrading the country's health system in terms of individual, managerial and organizational policies in health centers. Therefore, the physical needs, psychological and ergonomic pressures of the work environment and the health of the treatment staff can be improved.

Traffic accidents are one of the leading causes of death in pregnant women. One of the investment areas for maternal and neonatal health is targeted interventions to increase maternal safety to prevent traffic accidents. Therefore, this study was conducted with the aim of identifying and categorizing different types of safety interventions to reduce traffic accidents in pregnant women.

The study was a systematic review. Interventional articles from Persian databases including Magiran, Iran Medex, and SID, and English scientific information databases including PubMed, Cochrane, Sciencedirect, Embase, Science of Web, and Scopus were searched. All identified articles were collected by one person using Endnote software. Then, the full text of the articles was reviewed by two researchers and the articles that met the entry criteria were identified. Other articles were added to the previous collection of articles using forward citation and backward citation reviews. The EPHPP tool was used to assess the quality of the studies.

The initial search resulted in finding 5329 article abstracts. Eventually, two interventional studies were identified for evaluation in this study. The intervention approach used in one study was educational/behavioral and in the other was engineering/technology. Both studies reported that they had made significant changes in the desired outcomes, which was fastening the seat belt in pregnant women. One study was of poor quality in quality assessment and the other was of medium quality.

Safety interventions to reduce traffic accidents in pregnant women have been very little worked on worldwide. It seems that there is still much room for studies in the field of safety interventions to reduce traffic accidents among pregnant women.