Effect of Graphic Input Device and Repetition on Wrist Posture

This study investigated the Wacom Intuos2 pen and tablet and/or standard Microsoft mouse on wrist posture of 20 experienced users. Wrist posture, measured by extension, flexion, ulnar, and radial deviation, was compared across three independent variables: repetition (repetitive or alternative), input device (mouse and/or pen), and session (session 1 and session 2). Devices were used during a graphical computer task, which was repeated or alternated for two 30 minute test sessions. Neutral wrist range was defined within 15 degrees of 0 in any direction. Input device group interacted with session to significantly impact wrist extension, F (3, 16) = 9.42, p<.001 and ulnar deviation, F (3, 16) = 3.23, p<.05. When analyzing repetition while using the mouse, less extension was found than the pen. Both devices required movement outside the defined neutral range for extension. A significant repetition by session interaction effect for wrist flexion was revealed: F (1, 16) = 6.83, p<.05. The repetitive group revealed little to no flexion during the first session which was statistically different than the alternative group; both groups were inside the neutral range.