Fig 1.
The participants sat on a height-adjustable chair in front of a desk and performed a tracking task. All the participants used the same computer mouse and laptop computer (Dell, Inspiron 13” screen) placed 60 cm in front of them.
Fig 2.
The participants were assigned to one of four groups that differed in terms of the amount of practice on Day 1 and the time interval between Day 1 and Day 2. The gray parts of the bars represent rotation sessions, and the white ones represent non-rotation sessions. Groups 1 and 2 performed the task twice with a 24-h interval, while Groups 3 and 4 performed it twice with a 48-h interval. Groups 1 and 3 performed 10 sessions on Day 1, whereas Groups 2 and 4 performed 20 sessions on Day 1.
Fig 3.
Task performance of Group 1 and Group 2 (24-h-interval groups).
The horizontal axis represents the number of sessions of the tracking task, and the vertical axis represents the average error. The dashed line separates the results of Day 1 and Day 2. The blue line represents Group 1 (participants who performed 10 sessions on Day 1). The pink line represents Group 2 (participants who performed 20 sessions on Day 1). The open squares represent non-rotation sessions, and the filled circles represent rotation sessions. The background shadow shows the standard deviation of each group. The error increased in the second session on Day 1 in both the groups, after which it decreased.
Fig 4.
Task performance of Group 3 and Group 4 (48-h-interval groups).
The horizontal axis represents the number of sessions of the tracking task, and the vertical axis represents the average error. The dashed line separates the results of Day 1 and Day 2. The blue line represents Group 3 (participants who performed 10 sessions on Day 1). The pink line represents Group 4 (participants who performed 20 sessions on Day 1). The open squares represent non-rotation sessions, and the filled circles represent rotation sessions. The background shadow shows the standard deviation of each group. As with the 24-h-interval groups, the error increased in the second session on Day 1 in both the groups, after which it decreased.
Fig 5.
Aftereffects on Day 1 and Day 2.
The vertical axis represents the difference between the last rotation session and the first non-rotation session (baseline). A mixed-design ANOVA revealed a statistically significant interaction between the day of training and the amount of training (F(1,36) = 8.14, p < 0.001, ηp2 = 0.18) and the main effects of the amount of training on Day 1 (F(1,36) = 31.85, p < 0.001, ηp2 = 0.47). A post-hoc test revealed the simple main effect of the amount of training on Day 1 and Day 2 (F(1,36) = 34.52, p < 0.001, ηp2 = 0.49; F(1,36) = 11.78, p < 0.01, ηp2 = 0.25) and that of the day of practice in the 20-session groups (F(1,18) = 6.87, p < 0.05; ηp2 = 0.28). The aftereffects marked with asterisks were significantly higher in the 20-session practice groups than in the 10-session practice groups (all ps < .001).
Fig 6.
Savings in the experimental groups.
The vertical axis represents savings. The savings of the 20-session groups (Group 1, Group 3) was greater than that of the 10-session groups (Group 2, Group 4). A two-way ANOVA with the time interval (24 h, 48 h) and the amount of training on Day 1 (20 sessions, 10 sessions) as between-subject factors revealed the main effect of the amount of training (F(1,36) = 12.89, p < 0.001, ηp2 = 0.26). There was no significant interaction. The savings values marked with asterisks were significantly higher in the 20-session practice groups than in the 10-session practice groups (all ps < .001).