Analysis of Perceived Discomfort and EMG for touch locations of a soft keyboard

Abstract

With diversity of mobile services (e.g., messenger, and social network service) on smartphone, the demand of text input using a soft keyboard is increasing. However, studies on subjective and physiological responses of users for various touch locations are lacking. The present study investigated the ergonomic responses according to touch locations of a soft keyboard on smartphone. The experiment of the present study measured perceived discomfort using Borg's CR-10 scale and electromyography on forearm (abductor pollicis longus, and extensor digitorum communis) and thumb (abductor pollicis brevis, and first dorsal interossei) muscles. Perceived discomfort was significantly varied from 0.7 (extremely weak discomfort) to 2.5 (weak discomfort) depending on touch locations. %MVC at abductor pollicis brevis was significantly varied from 10% to 23% according to touch locations. The experimental results of the present study can be utilized in the ergonomic design of a soft keyboard. © Springer-Verlag Berlin Heidelberg 2013.