# An Agile Approach to Improve the Usability of a Physical Telechabilitation Platform
## 3 Materials and Methods
The experiment had 39 participants (32 males and seven females) for the third iteration and 12 participants (seven males and five females) for the fourth iteration, with an age range of 18-40 years old, all without experience in telexhabilitation platforms, but with experience in the use of computers, computer games, and browsers. A baseline was established to measure the usability attributes. This was an important part of the usability evaluation, because the baseline determined the current status of the interfaces and identified usability deficiencies based on recognized heuristics principles for specific applications, which in this case were web interfaces. The authors recommended starting the usability analysis with [PERSON]'s 10 heuristics principles [24] and this was complemented with three specific heuristics [27] for this platform. In an effort to further improve the usability of the ePHoRT platform, during the second phase (third and fourth iteration), the process proposed for the first phase was replicated [27]: (1) Sort and prioritize the results by severity; (2) Select a suitable methodology for developing improvements; (3) Make a change control request form and record the improvements to be made; (4) Re-evaluate and compare results; (5) Test and deploy the new improvements. The proposed process was improved for this study. Figure 2 illustrates the new schema for the usability improvement method. The new process to improve usability has three phases. In the first phase, which is called user requirements, the authors propose devising a list of requirements, and ordering and prioritizing them by the criterion level of severity. In the second phase, known as the development of improvements, the iterative schema proposed uses the agile software development method [34] to improve the interfaces. In this way, the evolution of the level of usability of the ePHoRT platform is obtained \begin{table}
\begin{tabular}{p{42.7 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Id** & **Task** & **Description** \\ \hline T1 & Open the learning object “How to move normally” of the stage 1 & In this task you should study the learning object “How to move normally” which is inside the “learn” option of the “stage 1” menu. You can select the learning mode you want (document, video, audio). \\ \hline T2 & Perform an active exercise of the stage 1 & In this task you should perform an active exercise from the stage. An active movement is a set of rehabilitation exercises. Please start the exercise and then proceed. \\ \hline T3 & See the new messages from the therapist & In this task you must go to the interface that allows you to read new messages. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Tasks for workload assessment. \begin{table}
\begin{tabular}{c p{113.8 pt}} \hline \hline
**Severity** & **Description** \\ \hline
0 & Cosmetic problem: need not be fixed unless extra time is available on project \\
1 & Minor usability problem: fixing this should be given low priority \\
2 & Major usability problem: important to fix, so should be given high priority \\
3 & Usability catastrophe: imperative to fix this before product can be released \\ \hline \hline \end{tabular}
\end{table} 
Table 3: [PERSON]’s severity scale for heuristic evaluations. through several iterations while keeping record of the changes made. In the third phase, the deployment of improvements phase, the improved interfaces are evaluated to check if the desired level of usability has been reached. If this is not the case then it is necessary to reevaluate and compare the results.