Iranian Journal of Ergonomics

Determining the Mental Workload and Investigating Its Effect on Changing the Mood Components of Taxi Drivers in the City of Qazvin

Seyed Abolfazl Zakerian

Objectives: Road accidents and related damages and casualties are among the most important concerns of today's societies. Mental workload is one of the main human factors that can cause other factors, such as stress and anger. The present study was conducted to investigate the mental workload and its effect on changing the components of drivers' moods.
Methods: A total of 88 tour taxi drivers from Qazvin City participated in this study to examine the desired components. The driving Activity Load Index was used to evaluate mental load and the Profile of Mood States questionnaire to measure drivers' mood components. Based on the designed scenario of driving on high-traffic roads, the desired variables were evaluated. To check the relationship between these variables, paired t-tests and Pearson correlation analysis were used in SPSS version 24 software.
Results: The mean scores of the drivers' work history and age were obtained at 46.60±10.12 and 13.47±9.39 years, respectively. The obtained findings showed that driving on high-traffic roads significantly increased the average mental workload of drivers (P<0.001). Growth in the drivers' mental workload led to a decrease in some mood components that had a positive effect, such as happiness (r=-0.143, P=0.157) and vitality (r=-0.646, P=0.050), while it resulted in a rise in the mood component of depression (r=0.020, P= 0.248).
Conclusion: Based on the findings of the study, it can be concluded that as driving continues, drivers experience a rise in mental workload. However, there was no correlation regarding the effect of this component on the mood components.

Prevalence of Musculoskeletal Disorders and its Association with the Work Ability Index among Staff Working in the Operating Room of Governmental Hospitals in Hamedan, Iran

Shirdel Zandi

Objectives: Musculoskeletal disorders are among the common problems in most work environments and work ability is considered a factor affecting the performance and productivity of employees. In the present study, the status of these two components and their relationship with each other in the staff working in the operating room were investigated.
Methods: The current cross-sectional study was conducted in the winter of 2023. In this research, 96 employees working in the operating rooms of government hospitals in Hamadan, Iran were enrolled by census sampling method based on the inclusion criteria. The data were collected through the Nordic standard questionnaire and the work ability index questionnaire. The collected data were analyzed in SPSS software (version 24) at two levels of descriptive (frequency, mean, and standard deviation) and inferential (t-test) statistics.
Results: In this study, 4 (4.2%) of the participants had one musculoskeletal disorder and the remaining 91 personnel (95.8%) had more than one disorder in their musculoskeletal systems. Average work ability index was 42.3±04.91. The results of the independent t-test showed that the work ability index among people with pain in the neck (P=0.003), shoulders (P=0.001), elbows (P=0.038), back (P=0.011), knees (P=0.001), and legs (P=0.002) were less than those without pain in these organs.
Conclusion: Results indicated the need to pay more attention to the implementation of ergonomic work environment and management interventions to reduce the prevalence of musculoskeletal disorders and thereby increase the efficiency and effectiveness of personnel.

Prediction of Musculoskeletal Disorders Based on People's Demographic Information Using Artificial Intelligence Methods and the Cornell Musculoskeletal Discomfort Questionnaire

Arezoo Sammak Amani

Objectives: Work-related musculoskeletal Disorders (WMSDs) are the most significant challenges in both developing and developed countries, affecting the majority of individuals throughout their lives. Considering the detrimental effects of musculoskeletal disorders on the productivity and general health of employees, this research utilizes the Cornell Musculoskeletal Disorder Questionnaire (CMDQ) to develop an intelligent model for assessing and predicting the levels of musculoskeletal disorders.
Methods: In this descriptive-analytical study, 810 employees from five organizations (in four occupational categories, including administrative, technical, production, and services) completed the CMDQ voluntarily. After collecting the questionnaire and performing relevant statistical analyses, data normalization and clustering based on the K-Means method were used to determine levels of musculoskeletal disorders. Finally, the multilayer perceptron artificial neural network was trained to predict the levels of musculoskeletal disorders; moreover, the criteria of precision, accuracy, recall, and F1-score were used to evaluate the proposed model.
Results: The performance of the proposed model in predicting the levels of musculoskeletal disorders is presented in two scenarios (use and non-use of the Synthetic Minority Oversampling Technique (SMOTE) method) based on the evaluation criteria provided. The accuracy, precision, recall, and F1-score values were 0.724, 0.709, 0.756, and 0.720, respectively. The appropriate accuracy and precision in the proposed model indicate its capability to identify the levels of musculoskeletal disorders in individuals and help healthcare professionals take necessary measures to prevent and predict them.
Conclusion: This study employs the CMDQ questionnaire and artificial intelligence to analyze musculoskeletal disorders in the workplace. The proposed model demonstrates significant accuracy and precision compared to similar studies. The results indicate that this model can be utilized to identify and predict musculoskeletal disorders in organizational employees, offering the potential to expedite the identification process and reduce costs.

Translation, Cross-cultural Adaptation, and Evaluation of Psychometric Properties of the CarMen-Q Mental Workload Questionnaire into Persian

Hamidreza Mokhtarinia

Objectives: Changes in mental workload are related to performance and level of fatigue, stress, human error, and job dissatisfaction. Questionnaires are simple, accessible, and valid tools for the assessment of mental workload. Therefore, the present study aimed at translation, cultural adaptation, and evaluation of psychometric properties of the Carmen-Q mental workload questionnaire.
Methods: This study was conducted on 296 subjects (100 women and 196 men) with a mean age of 38.59±7.61 years, working in industrial and administrative sectors in several centers in Saveh. The process of translation and cultural adaptation was carried out in accordance with relevant guidelines and included the stages of forward and backward translation, synthesizing and preparing a final version, piloting, and then final approval of the Persian version. Psychometric properties, including face validity (simplicity and readability), content validity (through content validity index), convergent validity (through correlation with NASA-TLX questionnaire), and internal consistency (using Cronbach's alpha coefficient) were assessed.
Results: The translation, cultural adaptation, and face validity assessment were carried out according to related guidelines, and the text underwent some minor changes. The Content Validity Index values for each of the items and its total (0.914) were acceptable. Cronbach's alpha value was acceptable for all items (0.91) and each subscale (above 0.8). Pearson's correlation coefficient displayed a moderate to good relationship between Carmen-Q and NASA task load index.
Conclusion: The Persian version of the Carmen-Q questionnaire is a valid and reliable tool for evaluating mental workload in Iranian society.

Investigating the Mediating Role of Self-efficacy in the Relationship between Role Ambiguity and Perceived Organizational Support on Employees' Well-being Based on JD-R Model

Mohammad Hassani

Objectives: Improving employees’ welfare and supporting them has led to the success of the organization. Employees who feel supported by the company will work harder to improve their output and meet the objectives of the company. Finding factors affecting employee well-being has helped organizations to improve performance and achieve success. Therefore, this research has sought to test a model of causal factors affecting employees' well-being with the mediation of self-efficacy among the employees of Razi University of Kermanshah.
Methods: The current applied research was conducted using a descriptive-survey method for data collection. The data collection tool was a questionnaire, which was examined for face validity, convergent validity, and differential validity of the variables. Data analysis was done using a structural equation modeling approach with a partial least squares method through Smart PLs3 software. The statistical population (n=490) included all employees of Razi University of Kermanshah, among whom, 215 individuals were selected as a sample using Morgan's table.
Results: The findings showed that perceived organizational support and role ambiguity were effective on employees' well-being both directly and through the mediation of self-efficacy.
Conclusion: According to the research findings, it can be concluded that ambiguity in employee roles lead to higher emotional burnout and lower well-being, while perceived organizational support can enhance both work engagement and well-being.

Evaluation of Anthropometric Fit of Faculty Members with Office Workstation Characteristics

Neda Mahdavi

Objectives: Musculoskeletal disorders are among the health challenges for faculty members, affecting their performance and work-related quality of life. The present study aimed to investigate the relationship between these disorders and the ergonomic features of their workstations.
Methods: This research was conducted among 22 faculty members after obtaining informed consent and using a census method. The prevalence of disorders was assessed using the Cornell questionnaire, and the evaluation of the workstation was performed using the Rapid Office Strain Assessment (ROSA) method. Then, 14 anthropometric dimensions (differentiated by gender) were measured, and 13 workstation characteristics were assessed. Finally, 11 criteria were used for anthropometric fitness evaluation. Moreover, data analysis was carried out using SPSS software (version 26).
Results: Approximately 46% of the participants had experienced pain and discomfort in one of the musculoskeletal areas, with the wrist, neck, shoulder, and lower back being the most affected areas, respectively. The ROSA results indicated that 22.73% of the participants' workstations required ergonomic improvements. The most significant mismatches were found in the criteria of 1) trunk length-chair backrest length, 2) thigh thickness in a seated position-distance between thighs and desk, and 3) shoulder width-chair seat width.
Conclusion: The signs of a connection between the high prevalence of musculoskeletal disorders and the lack of anthropometric compatibility/inadequate knowledge among faculty members in the field of ergonomics were observed. This issue underscores the importance of considering ergonomic/anthropometric characteristics of office desks and chairs during the procurement of office supplies and emphasizes the need to enhance ergonomics knowledge.

Assessment of Cargo Handling Ergonomics in One of the Airports of Iran

Fatemeh Assadian

Objectives: Cargo workers at Ahvaz Airport in Ahvaz, Iran are at risk of musculoskeletal disorders. In this regard, the present study aimed to investigate their carrying out tasks and postures.
Methods: In this descriptive-analytical study, the census method was used to select 21 cargo workers in Ahvaz Airport. Task analysis was carried out by Hierarchical Task Analysis (HTA) and Quick Exposure Check (QEC). Moreover, the Manual Handling Assessment Charts were used to evaluate the manual load. The tools employed in this study included observation, photography, and a Cornell Musculoskeletal Disorder Questionnaire (CMQD) questionnaire. Statistical calculations were performed in SPSS (version 16) and Spearman's correlation coefficient for the variables.
Results: Each of the cargo workers of Ahvaz airport moves an average of 400 bags per shift. Spearman's correlation coefficient showed a significant relationship between musculoskeletal disorders and the variables of age, height, and Body Mass Index with values of 0.002, 0.005, and 0.003, respectively. The QEC method was used to observe the worst postures with a numerical score between 50 and 70, which were related to the standing posture at the flat roller and the sitting posture in the aircraft cargo. The examination of the CMQD questionnaire revealed that 61.6%, 65%, and 62% of diseases were related to shoulder, arm, and back, respectively.
Conclusion: After job analysis by the HTA method and evaluation of the results through the QEC method, it was determined that loading and arranging luggage in the cart and cargo were the most risky tasks. Both the MAC and QEC methods also indicated the necessity of an immediate change in the process of moving luggage.

The Validity of the Native Non-sports Equation in Estimating the Maximum Aerobic Capacity of Adolescent Boys

Ebrahim Zarinkalam

Objectives: The maximum aerobic capacity (VO_2max) is the most important indicator of physical fitness, which is closely related to the general health of the body. Considering the problems of laboratory measurement of VO_2max, estimating VO_2max by non-exercise equations will be one of the alternative solutions. This study aims to evaluate the validity of the native non-exercise equation in estimating VO_2max of healthy adolescent boys.
Methods: The variables of age, height, weight, and body mass index were measured in 248 healthy boys aged 15 to 18. The subjects' VO_2max was measured and predicted by exercise test and non-exercise native equation respectively. To evaluate the validity of the native non-exercise equation, Pearson's correlation, paired t-test, and Bland-Altman's agreement were used.
Results: There is a significant correlation between measured and predicted VO_2max (R = 0.76, p<0.05). Also, no significant difference was observed between predicted and measured VO_2max (43.10 ml/kg/min and 43.38 ml/kg/min respectively) (mean difference=0.28 ml/kg/min, P>0.05). Also, the Bland-Altman graphic diagram indicated agreement between the methods of measuring and estimating VO_2max.
Conclusion: In the present study, the native non-sports equation had a high validity in estimating VO_2max of adolescent boys. It seems that the use of non-sports VO_2maxequations can be used as a simple, safe, and low-cost tool to evaluate the maximum aerobic capacity of students at a wide level.