Range of wrist movement (APDF Range) in term of extension/flexion for the (a) left (non-dominant) and (b) right (dominant) hand varied across different positions of tablet usage and virtual keyboard designs.

<p>Error bars represent +/- 1 SE. The conditions observed from the early 10–25 min period (left side) and later 55–60 min period (right side) are separated accordingly in each sub figure. Conditions with the same number (1, 2, 3) denote groups without significant difference across the usage positions within the same virtual keyboard design. Conditions with the same character (A, B, C) denote groups without significant difference across the keyboard designs within the same usage position.</p

(a) Elbow and (b) neck postures (50^th percentile) varied across different positions of tablet usage and virtual keyboard designs.

<p>Error bars represent +/- 1 SE. Conditions with the same number (1, 2, 3) denote groups without significant difference across the usage positions within the same virtual keyboard design. Conditions with the same character (A, B, C) denote groups without significant difference across the keyboard designs within the same usage position.</p

Least-square mean (SE) of the postural parameters for rANOVA main effects Position, Keyboard, Time, Gender and p-values for the interactions ¹².

<p>1 values are in degrees. Repeated measures ANOVA with Participants as a random effect and Position, Keyboard, Time, and Gender as fixed effects.</p><p>2 For each main dependent variable, the groupings based on the host hoc analyses are indicated by the superscript and ranked in a descending order such as A > B > C. The same superscript means no significant difference.</p><p>3 Negative values represent the wrist deviate toward the radial side.</p><p>Least-square mean (SE) of the postural parameters for rANOVA main effects Position, Keyboard, Time, Gender and p-values for the interactions <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143585#t002fn001" target="_blank">¹</a><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143585#t002fn002" target="_blank">²</a>.</p

Participant demographic characteristics and typing skills.

<p>Values are mean (± SD), WPM represents words per minute.</p><p>* Significant difference (p < 0.05) between male and female participants according to the results of Mann-Whitney U test</p><p>Participant demographic characteristics and typing skills.</p

Wrist (a) extension and (b) deviation postures (50^th percentile) varied across different positions of tablet usage and virtual keyboard designs.

<p>Error bars represent +/- 1 SE. Negative values in (b) represent the wrist deviate toward the radial side. The conditions observed from the left (non-dominant) and right (dominant) wrist are separated accordingly in each sub figure. Conditions with the same number (1, 2, 3) denote groups without significant difference across the usage positions within the same virtual keyboard design. Conditions with the same character (A, B, C) denote groups without significant difference across the keyboard designs within the same usage position.</p

Mean (SE) of body discomfort ratings in Borg CR-10 scale for rANOVA main effects Position, Keyboard, Time, Gender and p-values for the interactions ¹².

<p>1 values are in degrees. Repeated measures ANOVA with Participants as a random effect and Position, Keyboard, Time, and Gender as fixed effects.</p><p>2 For each main dependent variable, the groupings based on the host hoc analyses are indicated by the superscript and ranked in a descending order such as A > B > C. The same superscript means no significant difference.</p><p>Mean (SE) of body discomfort ratings in Borg CR-10 scale for rANOVA main effects Position, Keyboard, Time, Gender and p-values for the interactions <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143585#t003fn001" target="_blank">¹</a><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143585#t003fn002" target="_blank">²</a>.</p

The three positions of tablet usage evaluated.

<p>(a) DESK position, participants seated on an adjusted chair with the tablet on the desk. (b) LAP position, participants seated on an adjusted chair with the tablet on the laps. (c) BED position, participants seated on a bed with knees bent and the tablet on the thighs.</p

Range of wrist movement (APDF Range) in term of flexion/extension for the (a) elbow and (b) neck varied across different positions of tablet usage and virtual keyboard designs.

<p>Error bars represent +/- 1 SE. The conditions observed from the early 10–25 min period (left side) and later 55–60 min period (right side) are separated accordingly in each sub figure. Conditions with the same number (1, 2, 3) denote groups without significant difference across the usage positions within the same virtual keyboard design. Conditions with the same character (A, B, C) denote groups without significant difference across the keyboard designs within the same usage position.</p

Mean perceived usability of virtual keyboard designs varied across different positions of tablet usage.

<p>Conditions with the same number (1, 2, 3) denote groups without significant difference across the usage positions within the same virtual keyboard design. Conditions with the same character (A, B, C) denote groups without significant difference across the keyboard designs within the same usage position.</p

The three different designs of virtual keyboard evaluated.

<p>(a) STD design, the default layout provided in the tablet’s operation system. (b) WIDE design, the layout with broaden horizontal between-key spacing. (c) SPLIT design, the layout formed by two angled half keyboards</p