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Showing 4 results for Grip
The effect of non-powered hand tools' diameter on comfort and maximum hand torque
Mohammad Sadegh Sohrabi,
Volume 3, Issue 2 (9-2015)
Abstract

Introduction: The weak design of hand tools and their disharmony with the user's physical features comprise a major risk factor for upper limb musculoskeletal disorders. Hand-tool related injuries comprise almost 9% of all work-related injuries. The present study was conducted to examine the effect of hand tools' diameter on comfort and maximum hand torque and to estimate the optimal diameter for hand tools.

Methods: Participants included 6 men and 6 women with a mean age of 24.7 and a standard deviation of age of 5.84 years. Participants started to load and rotate the grip of 7 hand tools with different diameters with all their power and using a self-made tool for measuring the torque. The test duration, maximum torque and comfort level of the tool grip was then measured and the data obtained were analyzed using the ANOVA and the t-test.

Findings: The mean maximum torque value obtained was 1.88 (SD=0.95) newton meter, the time taken to reach the maximum torque was 13.96 (SD=9.03) seconds and the mean comfort level was 3.27 (SD=1.48) at a scale from 1 to 7. There was a significant difference between the maximum torque generated in the group of men and the group of women (p<0.001). The mean maximum torque obtained was 3.034 newton meter and the mean maximum comfort level was 4.67, achieved with a grip diameter of 38 mm.

Conclusion: The optimal hand tool diameter recommended for maximum user comfort and torque is 38 mm.


Measuring power hand grip strength in a sample of students aged 19-36 in Urmia
Teimour Allahyari, Sholeh Jafari, Hamidreza Khalkhali,
Volume 3, Issue 3 (12-2015)
Abstract

Background: Power and pinch hand grip strengths are major clinical and ergonomic parameters contributing to the hand muscle power. The data on hand grip strength measurements can have many benefits, including application in the design of hand tools. The present study was conducted to measure power hand grip strength among male and female students aged 19 to 36 using a Jamar Dynamometer and to compare their measurement data with the data obtained from other groups of the population.

Materials and Methods: The present cross sectional study was conducted on 234 male and female students aged 19-36 in Urmia University of Medical Sciences. Hand grip strength was measured using Jamar hand dynamometer and according to the Southampton protocol for adult grip strength measurement.

Results: The mean (±standard deviation of) hand grip strength calculated was 44.39 (±9.71) in the male students 20.48 (±5.86) in the female students. A high correlation was observed between the power hand grip strength in the left and right hands (r=0.94 and P<0.001) and a significant difference then between the power hand grip strength in the dominant and non-dominant hands. 

Conclusion: The findings of the present study and similar studies about power hand grip strength in the Iranian population can be used by ergonomists and manufacturers to improve the design of hand tools and the performance of tasks requiring hand muscle power.


Investigating the Relationship Between the Risk of Psychosocial Factors and Grip Fatigue of Employees with Manual Tasks
Neda Mahdavi, Javad Faradmal, Iman Dianat, Hassan Khotanlou, Rashid Haidari Moghadam,
Volume 8, Issue 3 (10-2020)
Abstract
Backgrond and Aim: 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. This research was conducted to assess grip fatigue between workers with manual tasks and its relationship to psychosocial risk factors.
Methods: 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 inclusion criteria 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.
Conclusion: Because 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.

Investigating the Effect of Wearing Medical Gloves on Grip Strength and Manual Dexterity
Fakhradin Ghasemi, Rashid Heidarimoghadam, Payam Khanlari,
Volume 9, Issue 3 (12-2021)
Abstract
Background and Objectives: Hospital and medical staff use medical gloves to protect themselves and their patients from infectious agents. Wearing gloves may reduce manual dexterity and grip strength and interfere with work performance. The aim of this study was to investigate the effect of wearing medical gloves on grip strength, manual dexterity, and perceived comfort.
Methods: 20 people (10 women, 10 men) participated in this study. Participants were tested in three gloveless modes, with latex gloves and with nitrile gloves with two tests, a 9-hole pegboard and a modified pegboard. Perceived comfort in working with gloves, wearing and removing gloves was also assessed using a subjective scale.
Results: The age range of participants was 20 to 40 years with an average of 29.45 years. There was a significant difference in manual dexterity between gloveless hands and nitrile gloves in the 9-hole pegboard test. In the modified pegboard test, gloveless hand manual dexterity was significantly different from both latex and nitrile gloves. The results also showed that wearing any type of glove significantly reduced the grip strength of individuals. The worst comfort rating was given to wearing gloves.
Conclusion: The results of this study showed that wearing gloves reduces manual dexterity and grip strength. A modified pegboard test is also recommended to assess the manual dexterity of medical gloves. Latex and Nitrile gloves are difficult to wear and should be considered in designs.

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