Affiliations: Ergonomics Laboratory, Department of Mechanical
Engineering, Aligarh Muslim University, Aligarh, UP, India
Note: [] Address for correspondence: Abid Ali Khan, Ergonomics
Laboratory, Department of Mechanical Engineering, Aligarh Muslim University,
Aligarh, UP, India. Tel.: +91 571 2700920, ext 1910; Fax: +91 571 2721375;
E-mail: abidak71@yahoo.com
Abstract: Objective: In the present study, bent-handled needle-nose pliers,
designed from an ergonomic perspective as an improvement over the conventional
plier were investigated. Participants: A convenience sample of fourteen
volunteer male university students aged between (20 and 24 years old)
participated in the study. Methods: Three angles to the jaws of plier
(0°, 10° and 20°) were provided in the redesigned
pliers to reduce ulnar deviation of wrist. Other two angles (0° and
5°) of jaws with respect to the vertical plane. From this, (3 ×
2) six redesigned pliers were investigated. Dependent variables were
discomfort – scored on 10~cm Visual Analogue Scale (VAS) and difference in
systolic and dysystolic blood pressure (BP). Results: The results of
ANOVA showed that the main and interaction effects of the angle to prevent
ulnar deviation of wrist and angle to prevent extension of wrist were highly
significant (i.e., p< 0.001) on discomfort score. Effect of angle to
prevent ulnar deviation of wrist was only found significant on difference in
systolic blood pressure. Of the redesigned pliers, the pliers with 10°
angle of handle from jaw to prevent ulnar deviation, and 5° angle of
handle to prevent extension of wrist was found to give the minimum level of
discomfort score. Conclusions: Hence it is concluded that bent handle
pliers up to certain angles may reduce discomfort, and after that discomfort
will increases drastically. These finding will be very significant for the
designers to use one more angle as per the requirement of the comfortable use
of pliers. Many ergonomically redesigned pliers are available. However none was
found be considering angle to give extension of the wrist based on scientific findings.
