The effects of different tablet tilt angles on posture control and muscle activity in tablet computer users

  • 張 文琳

Student thesis: Master's Thesis

Abstract

Background and purpose: The tablet computers offer a mobile computing experience and users operate it while lying sitting standing or walking Thus the tablet computer users may perform different postures to operate the tablet computer According to previous studies neck flexion increased significantly and muscle activity of neck increased as the tablet tilt angle decreased Wrist extension increased and muscle activity of wrist extensor increased as the tablet tilt angle increased Previous studies demonstrated that computer works were associated with a high prevalence of computer vision syndrome The higher perceived exertion and perceived comfort were also associated with developing musculoskeletal symptoms (MSDs) in the computer users Besides females were found to be at higher risk of MSDs than males on computer work However the relationship between the tablet computer and aforementioned parameters are still under investigation Three purposes of the current study were: first to investigate the effects of tablet tilt angle on body kinematic and kinetics in tablet computer users during performing tablet task; second to explore the time effects on tablet computer users; third to compare the gender differences in tablet computer users Method: Fifteen male and fifteen female adults who experienced with touch display inputs were recruited All participants executed the tablet computer task at four tablet tilt angles (0? 15? 50 ? and self-chosen tilt angle) While performing the tablet computer task posture of head neck trunk and upper extremity were recorded by motion captured cameras (Qualisys) Muscle activity of bilateral cervical erector spinae (CES) bilateral upper trapezius (Trap) bilateral anterior deltoid (AD) right extensor digitorum (RED) and right flexor digitorum superficialis (RFDS) were recorded Perceived exertion and comfort in six body regions as well as visual discomfort and blink rate were rated Also the preference of tilt angle in tablet computer users was recorded A three-way repeated measures analysis of variance (RMANOVA) on tilt angle gender and time was used to evaluate posture and muscle activity A two-way RMANOVA on tilt angle and gender was used to evaluate perceived exertion comfort and visual discomfort Whitney U test was used to compare the preference of tilt angle and blink rate Wilcoxon rank sum test was used to compare the preference of tilt angle and blink rate between gender groups In order to control for the confounding effects of body height a repeated measures analysis of covariance (RMANCOVA) was also used between genders Results: The head and neck postures became more erect as the tablet tilt angle increased (p
Date of Award2014 Sep 2
Original languageEnglish
SupervisorChiung-Yu Cho (Supervisor)

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