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Volume 8, Issue 3 (Iranian Journal of Ergonomics 2020)
Iran J Ergon 2020, 8(3): 48-58 |
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Mahdavi N, Faradmal J, Dianat I, khotanlou H, Haidari Moghadam R. Investigating the Relationship Between the Risk of Psychosocial Factors and Grip Fatigue of Employees with Manual Tasks. Iran J Ergon 2020; 8 (3) :48-58
URL: http://journal.iehfs.ir/article-1-731-en.html
URL: http://journal.iehfs.ir/article-1-731-en.html
1- Department of Ergonomics, School of Public Health and Research Center for Health Sciences, Hamadan university of Medical Sciences, Hamadan, Iran
2- Hamadan University of medical sciencesDepartment of Biostatistics, School of Public Health and Research Center for Health Sciences, Hamadan university of Medical Sciences, Hamadan, Iran
3- Department of Occupational Health and Ergonomics, Faculty of Health, Tabriz University of Medical Sciences, Tabriz, Iran
4- Department of Computer Engineering, Bu-Ali Sina University, Hamedan, Iran
5- Department of Ergonomics, School of Public Health and Research Center for Health Sciences, Hamadan university of Medical Sciences, Hamadan, Iran ,Dr_haidari@yahoo.com
2- Hamadan University of medical sciencesDepartment of Biostatistics, School of Public Health and Research Center for Health Sciences, Hamadan university of Medical Sciences, Hamadan, Iran
3- Department of Occupational Health and Ergonomics, Faculty of Health, Tabriz University of Medical Sciences, Tabriz, Iran
4- Department of Computer Engineering, Bu-Ali Sina University, Hamedan, Iran
5- Department of Ergonomics, School of Public Health and Research Center for Health Sciences, Hamadan university of Medical Sciences, Hamadan, Iran ,
Keywords: Grip Fatigue, Grip Force, Manual tasks, Psychosocial Risk Factors, Copenhagen questionnaire
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Table 2. Risk scores, psychological and social factors at different job levels
Table 3. Significant correlations between some factors of the Copenhagen questionnaire and grip force and grip fatigue
Extended Abstract: (1802 Views)
Introduction
Fatigue is a common and highly prevalent problem among workers. Muscle fatigue is the result of general fatigue that is caused by different risk factors. A review of the aforementioned studies raises this important question in mind: Do psychosocial causes affect muscle fatigue, especially arm fatigue, in workplace employees? By answering this question, appropriate and effective interventions can be made to improve productivity and prevent musculoskeletal disorders in valuable human capital. Therefore, the aim of this study was to investigate the relationships between different psychological and social aspects of the work environment with gripping force and gripping muscle fatigue among employees with different job tasks.
Materials and Methods
This cross-sectional study was conducted in 2019 and 2020 after approval by the Research Ethics Committee with the code IR.UMSHA.REC.1397.898. In this study, Jamar hydraulic dynamometer was used to investigate the decrease in the production of grip force or grip fatigue. The grip force of 157 subjects in three job levels that met the inclusion criteria was recorded, three times in an 8 hours shift. The psychosocial risk factors were also assessed using the Copenhagen psychosocial questionnaire and their relationship with grip force and grip fatigue was analyzed.
Results
Sixty-one percent, 62%, and 69% of employees in light, medium, and heavy tasks, respectively, experienced grip fatigue in the second phase of the study. It seems that as the power/speed increased and the tasks became more difficult, employees experienced more grip fatigue in the right hand. The declining trend of grip force and the increase in grip fatigue was more evident in heavy task jobs. No moderate or strong correlation was observed between the psychosocial risk factors and grip fatigue.
Table 1. The right and left hand gripping force of the subjects in three measurements separately for job level
| Repeating the test | Grip force (Newton) | M (SD) | P-value | |||
| Light manual tasks | Medium manual tasks | Heavy manual tasks | Whole people | |||
| The first measurement |
Right hand grip force | 22.22 (11.97) | 30.19 (12.15) | 39.38 (6.93) | 30.36 (12.70) | 0.001>0 |
| Left hand grip force | 20.55 (11.52) | 28.37 (12.47) | 37.78 (7.32) | 28.72 (12.64) | 0.001>0 | |
| The second measurement |
Right hand grip force | 23.24 (12.10) | 31.02 (12.68) | 40.24 (7.18) | 31.21 (12.94) | 0.001>0 |
| Left hand grip force | 21.90 (12.30) | 29.39 (13.11) | 39.03 (7.10) | 29.80 (13.18) | 0.001>0 | |
| Right hand grip force | 23.09 (12.36) | 30.90 (13.49) | 40.22 (7.23) | 31.33 (13.31) | 0.001>0 | |
| Left hand grip force | 21.55 (12.07) | 28.94 (13.55) | 38.60 (7.10) | 29.61 (13.22) | 0.001>0 | |
Table 2. Risk scores, psychological and social factors at different job levels
| Risk Factor | M (SD) | P-value | |||||||||
| Light manual tasks | Medium manual tasks | Heavy manual tasks | Total | ||||||||
| Factor 1 | 35.38 (15.60) | 27.37 (15.20) | 34.87 (15.90) | 32.16 (15.88) | *0.014 | ||||||
| Factor 2 | 37.50 (9.88) | 33.00 (10.87) | 33.67 (12.02) | 34.75 (10.98) | 0.078 | ||||||
| Factor 3 | 21.63 (14.50) | 18.25 (13.18) | 19.82 (14.76) | 14.07 (19.87) | 0.464 | ||||||
Table 3. Significant correlations between some factors of the Copenhagen questionnaire and grip force and grip fatigue
| Risk Factor | GF | The correlation coefficient | P-value |
| Factor 1 | Right hand grip force – start of work | 0.175 | 0.028 |
| Left hand grip force - start work | 0.164 | 0.040 | |
| Right hand grip force- middle of work | 0.157 | 0.023 | |
| Left hand grip force- middle of work | 0.157 | 0.048 | |
| Right hand grip force - end of work | 0.179 | 0.025 | |
| Right hand grip force - end of work | 0.157 | 0.049 | |
| Factor 2 | Fatigue of the right hand grip- middle of work | 0.243 | 0.004 |
Discussion
In this study, the reason for choosing a hand to examine muscle fatigue was the need to pay attention to the strength, delicacy, agility and skill of the hand in performing the most complex job tasks. The grip of the hand is an important job activity in every shift. Decreased strength during hand grip as a sign of muscle fatigue may be associated with ergonomic risk factors in the workplace. Therefore, in order to measure the fatigue of the large population of the present study, a dynamometer was used as an objective tool to measure the strength of the grip and consequently muscle fatigue. The results of the study showed that the gripping force of the right and left hand of heavy manual workers in all three measurements in the work shift was more than the average and light heavy workers (Table 1).
High grip seems to be associated with greater ability to perform work, especially in employees with manual tasks (47). Also, the right-handed and left-handed grips of the average manual tasks subjects in all three repetitions of the test were significantly higher than light manual occupations. Therefore, it can be concluded that with the increase in the amount of manpower required to perform job duties, the grip force of employees has also increased. This result indicated a greater ability to perform work in heavy manual workers. In line with the present study, in the study of Rostamzadeh et al., more traction force was reported in occupations that had more manpower required to perform their job duties (40). Although the trend of changes in the right and left hand gripping forces of employees in all three job levels did not differ significantly in the three measurements, at the end of the shift it was relatively more than the beginning of the shift. Contrary to the results of this study, Nicolay and Walker reported a decrease in grip force with increasing elapsed time (48); however, in line with the present study, Mantooth et al. did not observe a significant difference in fatigue levels before and after work shifts (49). Assessing the risk of psychological and social factors of employees showed a significant difference between factor 1 of the Copenhagen questionnaire (dimensions related to leadership style and organizational climate and communication) at different job levels. Examination of the correlation between psychosocial risk factors with grip force and grip fatigue showed that factor 1 of the Copenhagen questionnaire had a weak correlation with grip force of the right and left hands in three measurements. In addition, tangential fatigue in the second phase of the study had a weak correlation with factor 2 of the Copenhagen questionnaire.
Conclusion
Since the nature of worker tasks in heavy manual tasks required more force exertion, they experienced more grip fatigue in their right hand than other workers. It is not possible to draw definitive conclusions about the impact of psychosocial risk factors on grip fatigue. Investigating the impact of cognitive loads and anthropometric dimensions on grip fatigue can be an interesting topic for future studies.
Acknowledgements
This research has been done in the form of a research project with registration number 9803071031 and financial support of the Vice Chancellor for Research and Technology of Hamadan University of Medical Sciences. We, the researchers, thank and appreciate the authorities of this university.
Conflicts of Interest
The authors declared no conflict of interest.
Type of Study: Research |
Received: 2020/05/28 | Accepted: 2020/08/27 | ePublished: 2020/09/22
Received: 2020/05/28 | Accepted: 2020/08/27 | ePublished: 2020/09/22
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