# Applying Vision-Based Pose Estimation in a Telerehabilitation Application
## 3 Results
### ExerPlayer Usability Evaluation  
ExerCam, as well as other exergames, is an application oriented toward users, and as such, experience and satisfaction are important factors to take into account. For that reason, after the execution of the exercises, the system usability scale (SUS) [50] test was given to the therapist (see Table 7) and participants (see Table 8), allowing the assessment of the usability of the system from the perspective of the user.  
The SUS test is a test with a reasonable number of questions (10), easily understandable and widely validated and adopted for technological-based systems such as ExerCam. Each of its questions is rated on a Likert scale between 1 and 5 (from 1 for \"totally disagree to 5 for \"totally agree\") measuring usability. To respond to this test, it was a requirement that all participants had tested the complete system (in other words, calibration mode, task mode and game mode). Additionally, a comments section was added to allow the participants and therapist to leave any other comment they considered had not been reflected in the questions.  
To evaluate the results of the SUS test, we used the adjectives method (see Figure 10). This method is based on the association of the SUS score with an adjective scale (worst, poor, ok, good, excellent, best). In Figure 11, the results obtained from each participant and their average are shown. Acceptable values being considered are those between the adjectives good, excellent or best (that is, with a SUS score greater than 68), indicated by a horizontal red line in Figure 11.  
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Knee Flexion**} \\ \hline  & **S1** & **S2** & **S3** & \(\bar{\mathbf{X}}\) & **Absolute Error** & **Relative Error** \\ \hline
**ROM ExerCam (targets)** & 130 & 130 & 130 & 130 & 2.33 & 1.76\% \\
**ROM ExerCam (joints)** & 135 & 135 & 133 & 134.3 & 2 & 1.51\% \\
**ROM Manual** & 132 & 133 & 132 & 132.3 & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 6: Results of the measurements in the knee flexion task.  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**Questionnaire Item** & **I1** & **I2** & **I3** & **I4** & **I5** & **I6** & **I7** & **I8** & **I9** & **I10** & **Score** \\ \hline Answer & 4 & 2 & 4 & 2 & 5 & 1 & 5 & 1 & 5 & 1 & **90** \\ \hline \hline \end{tabular}
\end{table}
Table 7: SUS test therapist results.  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**Questionnaire Item** & \multicolumn{6}{c}{**Answer**} \\ \cline{3-8}  & & \multicolumn{6}{c}{**Answer**} \\ \cline{3-8}  & & **1** & **2** & **3** & **4** & **5** & \(\bar{\mathbf{X}}\) \\ \hline
11: I think that I would like to use this system frequently & 0 & 0 & 6 & 12 & 2 & 3.8 \\ \hline
12: I found the system unnecessarily complex & 14 & 5 & 1 & 0 & 0 & 1.35 \\ \hline
13: I thought the system was easy to use & 0 & 1 & 3 & 5 & 11 & 4.35 \\ \hline
14: I think that I would need the support of a technical person to be able to use this system & 2 & 8 & 2 & 2 & 6 & 3.1 \\ \hline
15: I found the various functions in this system were well integrated & 0 & 0 & 0 & 2 & 18 & 4.9 \\ \hline
16: I thought there was too much inconsistency in this system & 17 & 3 & 0 & 0 & 0 & 1.15 \\ \hline
17 I would imagine that most people would learn to use this system very quickly & 0 & 0 & 0 & 11 & 9 & 4.45 \\ \hline
18: I found the system very cumbersome to use & 12 & 6 & 2 & 0 & 0 & 1.5 \\ \hline
19: I felt very confident using the system & 0 & 0 & 1 & 16 & 3 & 4.1 \\ \hline
110: I needed to learn a lot of things before I could get going with this system & 18 & 2 & 0 & 0 & 0 & 1.1 \\ \hline \hline \end{tabular}
\end{table}
Table 8: SUS test participant results.