Xiong Jinghong, Muraki Satoshi
a Graduate School of Design , Kyushu University , Fukuoka , Japan.
Ergonomics. 2014;57(6):943-55. doi: 10.1080/00140139.2014.904007. Epub 2014 Apr 8.
This study investigated the relationships between thumb muscle activity and thumb operating tasks on a smartphone touch screen with one-hand posture. Six muscles in the right thumb and forearm were targeted in this study, namely adductor pollicis, flexor pollicis brevis, abductor pollicis brevis (APB), abductor pollicis longus, first dorsal interosseous (FDI) and extensor digitorum. The performance measures showed that the thumb developed fatigue rapidly when tapping on smaller buttons (diameter: 9 mm compared with 3 mm), and moved more slowly in flexion-extension than in adduction-abduction orientation. Meanwhile, the electromyography and perceived exertion values of FDI significantly increased in small button and flexion-extension tasks, while those of APB were greater in the adduction-abduction task. This study reveals that muscle effort among thumb muscles on a touch screen smartphone varies according to the task, and suggests that the use of small touch buttons should be minimised for better thumb performance.
本研究调查了单手姿势下，拇指肌肉活动与在智能手机触摸屏上进行拇指操作任务之间的关系。本研究针对右手拇指和前臂的六块肌肉，即拇收肌、拇短屈肌、拇短展肌（APB）、拇长展肌、第一背侧骨间肌（FDI）和指伸肌。性能测量结果表明，当点击较小按钮（直径：9毫米与3毫米相比）时，拇指会迅速产生疲劳，并且在屈伸方向上的移动比内收外展方向更慢。同时，在小按钮和屈伸任务中，FDI的肌电图和主观用力值显著增加，而在APB的内收外展任务中其值更大。本研究表明，触摸屏智能手机上拇指肌肉的用力程度会因任务而异，并建议应尽量减少使用小触摸按钮，以获得更好的拇指操作性能。
