Title: Effects of aspect ratio and the key position of the smartphone on thumb speed, muscle activities and discomfort in one-handed interaction

Authors: Bingyu Xu; Gang Guo; Qiuyang Tang

Addresses: College of Mechanical Engineering, Chongqing University, 400044 Chongqing, China ' College of Automotive Engineering, Chongqing University, 400044 Chongqing, China ' College of Automotive Engineering, Chongqing University, 400044 Chongqing, China

Abstract: This study aimed at investigating the effects of aspect ratio and key location on touch behaviours with one-handed interaction. Two aspect ratio devices (i.e., 16:9 and 18:9) and 15 key locations were examined. Thumb speed, electromyography, and subjective discomfort rating data were collected to examine the touch behaviour. The discomfort rating and electromyography deteriorated with high aspect ratio devices while tapping keys on the lower left of the screen. Higher thumb speeds were associated with adduction-abduction movement such as tapping keys on the lower left and top right. Key tapping with flexion-extension movements such as tapping keys on the lower right and top left tended to have more unsatisfactory subjective ratings and lower thumb speed. These results show that the keyboard design of high aspect ratio smart phones should avoid the common functions and buttons close to the lower left corner.

Keywords: smartphone aspect ratio; touch behaviour performances; one-handed interaction.

DOI: 10.1504/IJMC.2023.131819

International Journal of Mobile Communications, 2023 Vol.22 No.1, pp.111 - 124

Received: 28 Sep 2020
Accepted: 26 Sep 2021
Published online: 04 Jul 2023 *