An ergonomics study of thumb movements on smartphone touch screen

Abstract

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.

Neuronal control of the fingertips is socially configured in touchscreen smartphone users

“…Furthermore, volunteers ranked the fingers used according to their preference. Confirming previous findings for smartphone usage, the thumb was ranked by 73% of the users as most preferred on the touchscreen; 16% preferred the index finger; and 10% preferentially used both the thumb and the index finger (16, 31). Remarkably, only one user preferred their middle finger to all the other fingers.…”

Smartphone and Musculoskeletal Risk Factors: A Systematic Review

“…Using the medial side or pad/tip of the thumb exerted different effects on muscle activity; key pressing with the medial side of the thumb triggered high forearm exertion and increased muscle activity in the FDI [22]. Key size also influenced the FDI, with small keys increasing perceived exertion and level of activity to a level higher than that observed with large keys [20,23]. Efforts to stabilize a phone while the thumb engages in high-velocity movement was associated with high activity in the ED muscle [14,22].…”

“…The participants in the reviewed studies were primarily females (136 females and 116 males) and were in their 20s [2,5,8,11,[14][15][16][17][18][19][20][21][22]. Some of the study participants were more than 30 years old [11][12][13][14][15]; one study did not specify the age of the subjects.…”

“…Some of the study participants were more than 30 years old [11][12][13][14][15]; one study did not specify the age of the subjects. Eight articles indicated that the participants are right handed [2,16,18,20,21,[23][24][25][26][27]. In terms of phone characteristics, two studies used emulated phones with physical keypads [18,25], most of the studies involved SPs with touchscreens [2,5,8,15,16,[19][20][21]23,24,26,27], two examined mobile phones with physical keypads [14,22], and one examined two kinds of mobile phones with physical keypads and touchscreens [11].…”

An Ergonomic Study on Influence of Touch-screen Phone Size on Single-hand Operation Performance

“…However, the thumb is mostly likely to be used in the one-handed operation, while touching the screen, six muscles including adductor pollicis, flexor pollicis brevis, abductor pollicis brevis(APB), abductor pollicis longus, first dorsal interosseous(FDI) and extensor digitorum [2], are being used as shown in Figure 1. And these muscles get fatigue very fast on single-handed performance.…”