Assessment of Workload, Fatigue, and Musculoskeletal Discomfort Among Computerized Numerical Control Lathe Operators in Mexico

Development of a novel ergonomic index assessment in the workplace based on physical, cognitive, and environmental components

BACKGROUND

Currently, proper assessment of the existing ergonomic hazards, focusing on improving the health of individuals, is of great importance.

OBJECTIVE

This study aims to develop a new model for ergonomic index assessment in the workplace, focusing on physical, cognitive, and environmental components.

METHODS

To determine the parameters to be measured for each group of occupations, the most critical indicators in each ergonomic dimension were identified using a review of scientific texts and obtaining expert opinions. The opinions of 30 experts were studied in three stages Delphi study. Cronbach's alpha was used to calculate model reliability in SPSS version 25. An analytical hierarchy process was used to determine the weight values of each component and parameter. The weights were calculated in Expert Choice version 11.

RESULTS

The mean CVI and CVR values were 0.92 and 0.80, respectively. Cronbach's alpha values for each of the physical, environmental, and cognitive components and the entire model were 0.91, 0.87, 0.85, and 0.89, respectively. Physical components and parameters of physical condition during work, mental workload, lighting, and thermal stress in the workplace were among the most important parameters in the three groups of office, operational, and services jobs.

CONCLUSION

The model can be a practical step toward properly evaluating the ergonomic components and planning to implement control measures to reduce physical, cognitive, and environmental risk factors. Considering the study of different variables in occupational ergonomic risk assessment, this model can be a helpful tool in ergonomic management systems used in different occupational environments.

Effects of mental workload on manufacturing systems employees: A mediation causal model

BACKGROUND

Although some research has been done in the Mexican manufacturing industry regarding mental workload, none has explored its association with physical fatigue, body weight gain, and human error simultaneously.

OBJECTIVE

This research examines the association between mental workload and physical fatigue, body weight gain, and human error in employees from the Mexican manufacturing systems through a mediation analysis approach.

METHODS

A survey named Mental Workload Questionnaire was developed by merging the NASA-TLX with a questionnaire containing the mental workload variables mentioned above. The Mental Workload Questionnaire was applied to 167 participants in 63 manufacturing companies. In addition, the mental workload was used as an independent variable, while physical fatigue and body weight gain were mediator variables, and human error was a dependent variable. Six hypotheses were used to measure the relationships among variables and tested using the ordinary least squares regression algorithm.

RESULTS

Findings indicated that mental workload significantly correlates with physical fatigue and human error. Also, the mental workload had a significant total association with human error. The highest direct association with body weight gain was provided by physical fatigue, and body weight gain had an insignificant direct association with human error. Finally, all indirect associations were insignificant.

CONCLUSION

Mental workload directly affects human error, which physical fatigue does not; however, it does affect body weight gain. Managers should reduce their employees' mental workload and physical fatigue to avoid further problems associated with their health.

Development of an ergonomics management model in the workplace: Introduction of the TUGA ergonomics management and analysis model (TEMA)

BACKGROUND

Conducting practical studies in ergonomics requires attention to all aspects of ergonomics with a comprehensive approach and focus on continuous improvement cycles.

OBJECTIVE

This study aimed to develop and present an ergonomics management model in the workplace.

METHODS

This study was performed using a three-stage Delphi study with 30 experts and a fuzzy analytical hierarchy process. According to the literature review and experts' opinions, the general cycle of the ergonomics management system with eight steps was developed. New methods were formed in two of these eight steps: the 3rd step (developing an ergonomic evaluation method) and the 5th step (creating a cost-benefit evaluation method).

RESULTS

The eight implementation steps of the TEMA were determined as follows: 1) Performing task analysis (TTA), 2) Ergonomic hazard identification, 3) Estimating the ergonomic index, 4) Determining control measures, 5) Evaluating cost-benefit parameter, 6) Implementing control measures, 7) Continuous monitoring, and 8) Evaluating the effectiveness of control measures. The Delphi study revealed that the number of deleted parameters includes one item (burnout), and the remaining parameters were 16 items. The mean CVI and CVR values were 0.92 and 0.80, respectively. Cronbach's alpha values for each of the physical, environmental, and cognitive components and the entire model were 0.91, 0.87, 0.85, and 0.89, respectively.

CONCLUSION

Using the mentioned management model can be a practical step towards properly evaluating the most critical dimensions of ergonomics in the workplace and optimal planning to implement control measures to establish a dynamic management system to reduce ergonomic risk factors in the workplace.

Comparing workload and performance during demanding push force and mental tasks

BACKGROUND

The effects of performing occupational tasks that demand physical and mental efforts in combined and simultaneous approaches are unknown, especially when pushing force is analyzed as a physical effort and solving arithmetic problems as a mental effort.

OBJECTIVE

In this study, physical and mental demands were simulated in a lab environment to assess the workload.

METHODS

Using a push force dynamometer, the maximum push force strength of each participant was recorded, and the physical demand was simulated exerting the push force in low, medium, and high levels. Mental demands were simulated solving arithmetic tasks in low, medium, and high levels. Two experimental conditions were defined: (1) task with combined physical and mental workload (performing physical demands first and mental demands after) and (2) task in a simultaneous way (performing both demands at the same time. NASA-TLX Traditional and RAW were applied to assess the workload.

RESULTS

The time to complete the tasks was significantly longer in the combined than the simultaneous approach, and performance was significantly higher in the combined than the simultaneous tasks.

CONCLUSION

The combined approach obtained better results than simultaneous and Traditional NASA-TLX presented a significantly higher level of global workload index than RAW.

Effects of Fatigue and Grit on Club Sports Coaches

The objective of this research is to identify the level of general fatigue (FG), physical fatigue (FF) and concentration/motivation (C/M) in sports coaches. Two components of grit, consistency of interest (CI) and perseverance in effort (PE), are also assessed. The possible effects of sex, age, marital status, employment contract, work dedication and grit on FG, FF and C/M in sports coaches are examined. This cross-sectional study analyses 335 sports club coaches (21.2% women, 78.8% male) with a mean age of 29.88 (SD = 9.97) years, at a significance level of p < 0.05 for all analyses. Different aspects of fatigue were determined using the Spanish translation of the Multidimensional Fatigue Inventory-20 (IMF-20). The Grit-S scale was used to measure the ability to persevere, have passion and commit. The results indicated that men scored higher in FF, C/M and PE, while women obtained higher values in FG and CI. Non-contract coaches had higher FG, CI and PE, while coaches with contracts scored higher on C/M and FF. In conclusion, coaches with higher CI had higher FG, and high levels of PE were associated with low FG levels.

The relationship between individual, physical and psychosocial risk factors with musculoskeletal disorders and related disabilities in flight security personnel

Purpose. The purpose of this study was to investigate the relationship between individual, physical and psychosocial risk factors with musculoskeletal disorders and related disability in flight security personnel. Methods. The study was conducted among 316 employees in Iran flight security. To study the prevalence of musculoskeletal disorders, lifestyle, occupational stress, mental workload and disability, the Cornell questionnaire, Walker lifestyle questionnaire, job content questionnaire, NASA task load index and pain disability questionnaire were used, respectively. Data were analyzed using independent-sample t test, one-way analysis of variance, χ² test and multiple logistic regression. Results. A total 68.35% of participants had musculoskeletal disorders in at least one of their body parts. There was a significant relationship between the parameters of increased age, higher work experience, high body mass index, gender and educational level and the prevalence of musculoskeletal disorders. Also, some components related to healthy lifestyle, occupational stress and mental workload had significant association with mentioned disorders (p  < 0.05). Conclusion. The parameters of lifestyle, occupational stress and mental workload are among the most important risk factors for the prevalence of work-related musculoskeletal disorders and related disabilities in flight security personnel. Therefore, corrective measures through controlling individual, physical and psychosocial risk factors are necessary.