## 2 Materials and Methods  
The data collection sample consists of 15 individuals aged between 19 and 24, averaging 21 \(\pm\) 1.25 years. The group had a mean height of 1.69 \(\pm\) 0.09 m (m) and a mean Body Mass Index (BMI) of 23.45 \(\pm\) 4.48 kg/m\({}^{2}\). The Ethics Committee of the Polytechnic University of Coimbra approved the study (104 CEIPC/2021). All participants were duly informed of the intended objectives and methodology and voluntarily signed an informed consent form. This study considers two devices, Novel's Pedar(r) insoles and Sensing Future Technologies' Physiosensing(r) platform. A test protocol was established that outlined the steps to be taken before the acquisition, the volunteers' posture, and the acquisitions' duration and intervals. To ensure that all tests were conducted under the same conditions, each volunteer received instructions from the same researcher on the required posture: feet should be shoulder-width apart, torso should be upright, arms should be at the sides of the body, and gaze should be directed at a marked point located 2 m high and 3.5 m away from the volunteer. Data collection involved at least five valid acquisitions, each lasting 30 s, with a 30 s interval between each acquisition. All tests were conducted in a laboratory room, with temperature and humidity controlled. The same researcher controlled the data acquisition in all tests. Table 2 shows technical characteristics of Novel's Pedar(r) insoles and Sensing Future Technologies' Physiosensing(r) platform. For data collection, both devices used the same acquisition frequency (100 Hz). Each device has its software for data acquisition. Despite being different, each software also allows the monitorization of the evolution of plantar pressure through images. This study evaluated only two parameters: the contact area and the maximum peak pressure (MPP), considered enough for the study purposes. The Pedar(r) software (novel gmbh, Munich, Germany) includes tools that enable detailed data analysis, allowing the user to study the values for each measurement instantly and automatically calculate the average and standard deviation of several parameters for each trial. Therefore, it is possible to access data relating to the left and right foot regarding the contact area, the maximum force, and the peak pressure. Standardization is required since the contact area varies among devices and trials. Therefore, new variables were created to calculate the total contact area (AT) by using the areas of the left (AL) and right feet and (AR) as the contact areas of the left and right feet, respectively. \[\text{A\_T}=\text{A\_L}+\text{A\_R} \tag{1}\]  
Pedar(r)'s software also allows visualization of the distribution of plantar pressure. At least five valid trials were conducted for each volunteer, and the average total contact area and MPP values were calculated. The Physiosensing(r) software allows data collection regarding contact area, MPP, center of pressure coordinates, and average pressure value (MVP), among other parameters not considered in this study. Furthermore, the software presents a document summarizing the analyses conducted, encompassing qualitative (an image of the plantar pressure distribution) and quantitative (calculated parameters) aspects. Figure 1 shows an extract from this document. To align with the standardization process used in the Pedar(r) analysis and to achieve comparable values among both equipment types, the averages of the contact area and MPP of the five tests conducted on each volunteer were also calculated.