F8-3　The Effects of Smartphone Edge Display on EMG Activity of Thumb Muscles in One-handed Interaction

抄録

The purpose of this study is to investigate the effect of edge display of smartphone on thumb muscles activity of smartphone users. Sixty-six participants between 20 and 39 years were recruited in the experiment. Participants performed the two tasks which were touch and swipe, which were the most used tasks in smartphone. The independent variable was a smartphone display type (flat display, edge display). The experiment was conducted using a commercially available smartphone. Participants performed the tasks with two size of smartphone while walking or sitting. For checking muscles activity, we attached the surface electromyography (EMG) device to the subjects’ hands (especially their thumbs). Two muscles, the first dorsal interosseous (FDI) and the abductor pollicis brevis (APB), were chosen for this study. The results showed that only FDI muscles activity of the edge display smartphone was higher than that of the flat display smartphone, especially in big size smartphone conditions. This excessive muscle activity while using the edge display smartphone can cause musculoskeletal disorders to the user. This study suggests that the smartphone, which is a device that repeats the same thing over and over again, should be designed to decrease user muscle stress.