# A Mobile Gait Training System Providing an Active Interaction
## 3 Experiment
### Experimental Results
#### 3.2.2 Result of the Usability Evaluation  
Usability evaluation was conducted as shown in Figure 11 below. By providing the trainee with highlighted virtual footprints to be stepped on, and by providing positive feedback with the next virtual footprints when the trainee stepped on the virtual footprint correctly (as described earlier, it is considered correct if the foot is recognized for 1 s with more than 30% overlapping with the virtual footprint (gait guide)). When recognition failed (if the trainee did not step properly on the provided virtual footprint), it provided negative feedback (incorrect) and encouraging feedback at the same time, allowing the training to continue. The questions for usability evaluation analysis were classified into three types as follows. Q1, Q2, and Q3 were classified as evaluation types for the system, Q4, Q5, and Q6 as evaluation types for feedback of the content, and finally Q7 and Q8 as evaluation types for virtual footprints (walking guide) of the content. The evaluation results for each of the three types are shown in Figure 14 below. Figure 14: Satisfaction based on evaluation types. Figure 13: Graph of the experiment result for foot recognition. \begin{table}
\begin{tabular}{c c} \hline \hline
**Variable** & **Value** \\ \hline H & 0.635 \\ \hline Df & 0.635 \\ \hline \(p\)-value & 0.727 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Result for foot recognition experiment—Kruskal–Wallis Test. As a result of the evaluation, it was confirmed that the satisfaction of the system was higher than that of the content in general. The Kruskal-Wallis test was performed to confirm whether the measured results were significant, and the results are shown in Table 4.  
As a result of the Kruskal-Wallis test, it was confirmed that the satisfaction on the three evaluation types was not statistically significant as the \(p\) value was greater than 0.05. In other words, since the three types do not have a significant effect on satisfaction, the questions cannot be analyzed by types. Therefore, the 7-point scale of each question was converted into a percentage and then analyzed as follows based on the average value. Result for usability evaluation was shown in Table 5. Q1 was a question about maintaining the distance of the moving part, scored an average of 83.375 points, and the SD and SE were second highest. The results imply that an error may occur due to a slip phenomenon when the robot is moving. Q2 was a question about the speed of the system movement, with an average score of 85.4125 points, indicating that the speed of the system movement is appropriate. Q3 was a question about the safety of the system and scored an average of 93.75 points. As the safety of this system was verified, it is thought that it may be used for actual gait training later on. Q4 was a question about positive feedback, and the highest average among feedback, 89.5878 points, was obtained. With the positive feedback, it is confirmed that the trainee could have the greatest motivation. Q5 obtained 81.2375 points with the lowest average as a question about negative feedback, meaning that it is confirmed that negative feedback was useful for gait training, but not helpful compared to other feedback (positive, encouraging). Q6 was a question about encouraging feedback and scored an average of 83.325 points. For Q6, 33.3 points (3 points on a 7-point scale) as the lowest, 100 points (7 points on a 7-point scale) as the highest, and SD and SE appeared to be the highest. This suggests that the motivation effects among trainees may appear differently. Since it can be either a disturbance for some trainees or a motivating factor for others, it would be necessary to provide more general encouragement feedback before applying it to actual gait training. Q7 was a question about the spacing of the gait guide (virtual footprints) and earned 87.5 points which was the second highest average. Q8 was a question about the size of the gait guide (virtual footprints) and earned 85.4125 points.