## 3 Results  
### \"Virtual-Real\" Comparison of Material Pressure Properties  
Firstly, the real pressure (PR) measurement was conducted following the aforementioned pressure testing procedure to record the pressure data provided by five materials under different elongation conditions. Subsequently, the same virtual pressure (PV) measurement was then performed in the virtual system. After the measurement was completed, the normality test of the data was conducted. The Shapiro-Wilk results are shown in Table 4.  
The test results of normality show all \(p\) values > 0.05; that is, the PR and PV measured values follow a normal distribution. Further, the results of variance homogeneity test are shown in Table 5. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Test Parts**} & \multicolumn{3}{c}{**Shapiro–Wilk (PR)**} & \multicolumn{3}{c}{**Shapiro–Wilk (PV)**} \\ \cline{2-7}  & **Statistic** & **df** & **Sig.** & **Statistic** & **df** & **Sig.** \\ \hline Waist & 0.934 & 20 & 0.187 & 0.930 & 20 & 0.156 \\ Hip & 0.939 & 20 & 0.233 & 0.940 & 20 & 0.239 \\ Thigh & 0.944 & 20 & 0.291 & 0.940 & 20 & 0.245 \\ Mid-Thigh & 0.947 & 20 & 0.318 & 0.946 & 20 & 0.316 \\ Knee & 0.962 & 20 & 0.575 & 0.939 & 20 & 0.227 \\ Calf & 0.940 & 20 & 0.237 & 0.943 & 20 & 0.271 \\ Ankle & 0.944 & 20 & 0.280 & 0.960 & 20 & 0.545 \\ \hline \end{tabular}
\end{table} 
Table 4: Tests of normality. Figure 2: Test location and points. The pressure values of each test point under different postures also passed the homogeneity test of variance (\(p\) value \(>\) 0.05). The two groups of PR and PV have the same number of samples, the same test methods, and the sequence also has a one-to-one correspondence, so the paired \(t\)-test can be performed for analysis to observe whether there is a significant difference between the two groups of data (Table 6). Table 6 gives the results of statistical test, \(t\) = 4.246 and \(p\) value \(<\) 0.05, indicating that there is a significant difference between the measured and virtual pressure values. However, the mean difference in the data is not large (0.086 kPa). It is necessary to further analyze the PV and PR data to obtain accurate results for the later simulation. After descriptive statistical analysis, Figure 3 shows the comparison of PV and PR data and the mean percentage difference (\(n\) = 28). It can be found from the data distribution that the PV and PR data of the five materials are consistent overall. With the increase in the stretch (within the range of 20%), the percentage difference between the PV and PR data showed a decreasing trend (Figure 3f), range from 29.2%, 25.4%, 14.7%, to 9.8%. In Table 7, the average difference between PV and PR is not obvious. The \(\mathrm{Df_{(Max\cdot Min)}}\) range of PR is greater (0.59...1.31 kPa), the PV range is smaller (0.79...1.10 kPa), and the low-pressure PV data are significantly higher, especially when the material elongation (E) \(\geq\) 10%. Due to the rigid characteristics of the model, the flexible parts of a real body cannot be expressed, so the median PV is too large. Moreover, the complex flexible features of a body need to be considered. The pressure data can be subdivided into two categories: one for the flexible soft tissue parts with smaller curvature parts, such as the five girths of the waist, hips, thighs, mid-thighs, and calves; and the other for the rigid human skeletal parts with a large curvature, such as the girths of the knees and an