DEVELOPMENT OF THE ERGONOMIC MAXIMUM WRIST POSTURE FOR INDONESIAN USING ELECTROMYOGRAPH
Abstract
Carpal Tunnel Syndrome (CTS) is one of the most common neuropathies which occurs
due to repetitive activity of hand using non-neutral wrist posture whether in flexion,
extension, or ulnar and radial. Even though this posture may be inevitable, however it
should be confined in the ergonomic maximum range. Thus, it is necessary to develop the
allowable of maximum deviation of wrist. Objective of this study is to determine the
maximum range of wrist postures in such four motions with evaluating the muscle
contraction at wrist. A case study applied is to type a manuscript using computer.
Experimental study was conducted by using electromyograph to identify Maximum
Voluntary Contraction (MVC) on Flexor Digitorum Superficialis (FDS) and Abductor
Pollicis Brevis (APB), two of muscles which moves the finger and innervated by Median
Nerve, the only nerve through Carpal Tunnel. Fourteen healthy university students (7
females, 7 males) participated in the study with age between 20 to 23. They fulfilled the
requirements as study participants which are proficient in operating computers and had
no evidence of CTS and wrist musculoskeletal disorders. The statistical analysis was
conducted to test the hypothesis. Result of this study shows that as the angle inclination
increases in both extension, flexion, ulnar, and radial writs motion, the muscle
contraction were increasing and typing performance which showed WPM were
decreasing. Based on %MVC as well as statistical analysis, the suggested maximum wrist
posture range is not greater than 30˚ extension, 20˚ flexion, 20˚ ulnar, and 10˚ radial,
although the neutral posture of 0˚ was highly suggested. This guideline is proven to be
valid for both male and female.
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- Industrial Engineering [2224]