title: Thumb performance of elderly users on smartphone touchscreen.
abstract: This study investigated the relationship between thumb muscle activity and thumb operating tasks on a smartphone touchscreen in elderly users (right hand posture). Three thumb muscles were targeted in the experiment, namely, abductor pollicis brevis, abductor pollicis longus (APL) and first dorsal interosseous (FDI). The results showed that the elderly participants developed fatigue rapidly and tapped more slowly when operating on smaller buttons (diameter 3.0 mm compared with 9.0 mm) and moving in the flexion-extension (compared with adduction-abduction) orientation. Meanwhile, electromyography and perceived exertion evaluation revealed significant increases in FDI in the small button task, and results for APL were significantly greater in the flexion-extension task. This study suggests that the use of small touch-buttons and flexion-extension movement should be minimised in the handheld touchscreen interface design for elderly users.
authors: Graduate School of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka City, 815 8540 Japan.
authors: Jinghong
authors: J
authors: Xiong
authors: Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka City, 815 8540 Japan.
authors: Satoshi
authors: S
authors: Muraki
keywords: EMG; Elderly; Perceived exertion; Smartphone touchscreen; Thumb