Hum Factors. 2014 Nov;56(7):1235-48. doi: 10.1177/0018720814531784.
We investigated whether different virtual keyboard key sizes affected typing force exposures, muscle activity, wrist posture, comfort, and typing productivity.
Virtual keyboard use is increasing and the physical exposures associated with virtual keyboard key sizes are not well documented.
Typing forces, forearm/shoulder muscle activity, wrist posture, subjective comfort, and typing productivity were measured from 21 subjects while they were typing on four different virtual keyboards with square key sizes, which were 13, 16, 19, and 22 mm on each side with 2-mm between-key spacing.
The results showed that virtual keyboard key size had little effect on typing force, forearm muscle activity, and ulnar/radial deviation. However, the virtual keyboard with the 13-mm keys had a 15% slower typing speed (p < .0001), slightly higher static (10th percentile) shoulder muscle activity (2% maximum voluntary contractions, p = .0 I), slightly greater wrist extension in both hands (2 degrees to 3 degrees, p <.01), and the lowest subjective comfort and preference ratings (p < .1).
The study findings indicate that virtual keyboards with a key size less than 16 mm may be too small for touch typing given the slower typing speed, higher static shoulder muscle activity, greater wrist extension, and lowest subjective preferences.
We evaluated the effects of virtual keyboard key sizes on typing force exposures, muscle activity, comfort, and typing productivity.
我们研究了不同虚拟键盘按键尺寸是否会影响打字力度、肌肉活动、手腕姿势、舒适度和打字效率。
虚拟键盘的使用正在增加，而与虚拟键盘按键尺寸相关的物理暴露情况尚未得到充分记录。
21 名受试者在四种不同的虚拟键盘上打字时，我们测量了他们的打字力度、前臂/肩部肌肉活动、手腕姿势、主观舒适度和打字效率，这些虚拟键盘的方形按键尺寸分别为 13、16、19 和 22 毫米，键与键之间的间隔为 2 毫米。
结果表明，虚拟键盘按键尺寸对打字力度、前臂肌肉活动和尺骨/桡骨偏斜的影响较小。然而，按键尺寸为 13 毫米的虚拟键盘的打字速度慢了 15%（p<.0001），静态（第 10 百分位）肩部肌肉活动略高（2%最大自主收缩，p=.01），双手的手腕伸展度略大（2 度至 3 度，p<.01），且主观舒适度和偏好评分最低（p<.1）。
研究结果表明，由于打字速度较慢、静态肩部肌肉活动较高、手腕伸展度较大以及主观偏好最低，按键尺寸小于 16 毫米的虚拟键盘可能不适合触摸打字。
我们评估了虚拟键盘按键尺寸对打字力度暴露、肌肉活动、舒适度和打字效率的影响。
