## 3 Results
### Outcome Measurements  
Statistically significant differences (\(p\) \(<\) 0.05) were shown for Pmax and all peak plantar pressure regions of the foot among the different mat hardnesses during running, with the exception of PP5, showing that the peak pressure of the longitudinal arch of the foot did not differ significantly among these mats (Table 1).  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Outcome** & \multicolumn{2}{c}{**Soft Mat**} & \multicolumn{2}{c}{**Hard Mat**} & \multicolumn{2}{c}{**Air Chamber Mat**} & \multicolumn{2}{c}{**Friedman**} & \multicolumn{2}{c}{**Wilcoxon**} \\ \cline{2-10}
**Measurement** & **Median** & **IR** & **Median** & **IR** & **Median** & **IR** & **Chi** & \(p\)**-Value * & **Z** & \(p\)**-Value \(\dagger\)** \\ \hline Pmax & & & & & & & & & (a) \(-\)5.185 & (a) \(<\)0.01 \\ (N) & 174.50 & 148.25 & 272.50 & 184.25 & 310.50 & 250.25 & 46.58 & \(<\)0.01 & (b) \(-\)5.216 & (b) \(<\)0.01 \\  & & & & & & & & & (c) \(-\)1.483 & (c) 0.138 \\ \hline PP1 & & & & & & & & (a) \(-\)4.243 & (a) \(<\)0.01 \\ (N/cm\({}^{2}\)) & 5.30 & 3.38 & 7.05 & 5.88 & 6.80 & 6.70 & 19.98 & \(<\)0.01 & (b) \(-\)3.355 & (b) 0.001 \\  & & & & & & & & (c) \(-\)1.202 & (c) 0.229 \\ \hline PP2 & & & & & & & & (a) \(-\)4.814 & (a) \(<\)0.01 \\ (N/cm\({}^{2}\)) & 3.05 & 3.28 & 5.65 & 7.25 & 6.45 & 9.30 & 40.62 & \(<\)0.01 & (b) \(-\)5.131 & (b) \(<\)0.01 \\  & & & & & & & & (c) \(-\)3.009 & (c) 0.003 \\ \hline PP3 & & & & & & & & (a) \(-\)4.587 & (a) \(<\)0.01 \\ (N/cm\({}^{2}\)) & 2.90 & 1.63 & 5.15 & 3.13 & 5.15 & 2.57 & 29.67 & \(<\)0.01 & (b) \(-\)4.808 & (b) \(<\)0.01 \\  & & & & & & & & (c) \(-\)1.434 & (c) 0.151 \\ \hline PP4 & & & & & & & & (a) \(-\)2.628 & (a) 0.009 \\ (N/cm\({}^{2}\)) & 3.00 & 1.90 & 4.00 & 1.93 & 3.80 & 2.05 & 8.13 & 0.017 & (b) \(-\)1.591 & (b) 0.112 \\  & & & & & & & & (c) \(-\)1.317 & (c) 0.188 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison of in-shoe maximum forces and peak plantar pressures for different foot regions (Figure 1D) in mats with different hardness (hard, soft and air chamber) during running.  
Post-hoc comparisons showed that the Pmax median of the whole foot plantar region was lower (\(p\) < 0.01) during running on soft mats with 174.50 N than hard and air chamber mats with 272 and 310 N, respectively. In line with these findings and the Figure 1D regions, the median peak plantar pressure values of the toes (PP1), head of the first metatarsal (PP2) and region of the second, third and fourth metataralsals (PP3) were also lower (\(p\) < 0.01) during running on soft mats (varying from 2.90 to 5.30 N/cm\({}^{2}\)) than hard and air chamber mats (varying from 5.15 to 7.05 N/cm\({}^{2}\) and from 5.15 to 6.80 N/cm\({}^{2}\), respectively). In addition, running on air chamber mats increased the median peak pressure value of the first metataralsal head (PP2) up to 6.45 N/cm\({}^{2}\). Only the median peak pressure of the fifth metataralsal head (PP4) was lower (\(p\) = 0.009) on soft mats (with 3.00 N/cm\({}^{2}\)) than hard mats (with 4.00 N/cm\({}^{2}\)), while only the median peak pressure of the calcaneus (PP5) was lower (\(p\) = 0.005) on soft mats (with 1.70 N/cm\({}^{2}\)) than air chamber mats (with 2.05 N/cm\({}^{2}\)). The rest of the comparisons did not show statistically significant differences (\(p\) > 0.05).