## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \begin{tabular}{c} **Outcome** \\ **Measurement** \\ \end{tabular} & \multicolumn{2}{c}{**Soft Mat**} & \multicolumn{2}{c}{**Hard Mat**} & \multicolumn{2}{c}{**Air Chamber Mat**} & \multicolumn{2}{c}{**Friedman**} & \multicolumn{2}{c}{**Wilcoxon**} \\ \hline \multirow{2}{*}{\begin{tabular}{c} **Median** \\ \end{tabular} } & **IR** & **Median** & **IR** & **Median** & **IR** & **Chi** & \(p\)**-Value * & **Z** & \(p\)**-Value \(\dagger\)** \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} PP5 \\ (N/cm\({}^{2}\)) \\ \end{tabular} } & \multirow{2}{*}{1.70} & \multirow{2}{*}{1.57} & \multirow{2}{*}{1.70} & \multirow{2}{*}{1.98} & \multirow{2}{*}{2.05} & \multirow{2}{*}{2.43} & \multirow{2}{*}{8.71} & \multirow{2}{*}{0.138} & (a) \(-\)1.139 & (a) 0.255 \\ \cline{4-4} \cline{8-10}  & & & & & & & & (b) \(-\)2.320 & (b) 0.020 \\ \cline{4-4} \cline{8-10}  & & & & & & & & (c) \(-\)1.747 & (c) 0.081 \\ \hline \multirow{2}{*}{
\begin{tabular}{c} PP6 \\ (N/cm\({}^{2}\)) \\ \end{tabular} } & \multirow{2}{*}{2.70} & \multirow{2}{*}{1.88} & \multirow{2}{*}{2.40} & \multirow{2}{*}{1.73} & \multirow{2}{*}{2.05} & \multirow{2}{*}{1.70} & \multirow{2}{*}{11.61} & \multirow{2}{*}{0.003} & (a) \(-\)1.497 & (a) 0.134 \\ \cline{4-4} \cline{8-10}  & & & & & & & (b) \(-\)2.805 & (b) 0.005 \\ \cline{4-4} \cline{8-10}  & & & & & & & (c) \(-\)2.349 & (c) 0.019 \\ \hline \hline \end{tabular} Abbreviations: Fmax, maximum force; PP1, peak pressure of the toes (Figure 1D); PP2, peak pressure of the head of the first metataralsal (Figure 1D); PP3, peak pressure of the region of the second, third and fourth metataralsalsals (Figure 1D); PP4, peak pressure of the head of the fifth metataralsal (Figure 1D); PP5, peak pressure of the longitudinal arc of the foot (Figure 1D); PP6, peak pressure of the calcaneus (Figure 1D). * \(p\)-value was statistically significant at \(p\) < 0.05 for a 95% confidence interval: \(\dagger\)-\(\dagger\)-value was statistically significant at \(p\) < 0.016 according to [PERSON]’s corrections for post-hoc comparisons: (a) Soft versus hard mats; (b) Soft versus air chamber mats; (c) Hard versus air chamber mats.  
\end{table} 
Table 1: _Cont._pressures were analyzed during linear running on surfaces of different hardness such as cement, asphalt, rubber and natural grass, showing lower pressures while running on soft surfaces such as grass than running on hard surfaces such as cement and asphalt, especially for the forefoot and medial regions of the foot [23]. The study findings could play a key role in training, injury prevention and the return to sport after an injury, since the practice of running or skipping is an important part of both sport training and injury recovery [25]. The mechanical behavior of different mat hardnesses enabled us to know their degree of impact by plantar pressures in order to choose the most appropriate materials and hardness for running. This fact was based on the \"spring mass\" model, which claims that the lower limb tension is adjusted to the training surface [26]. According to our study findings, some considerations could be taken into account for guiding the rehabilitation training of runners and should be further analyzed in future studies. Foot-strike and the associated load rate are factors related to overuse injuries in the hindfoot during running [27], such as Achilles tendonopathies and plantar fasciopathy [28]. Interventions to reduce pain in hindfoot injuries consist of reducing load ratios during running, for example, by using floating-heel shoes or foot orthoses [27]. Therefore, training on soft mats for runners with hindfoot pain could be used for the recovery of these pathologies. In addition, our study findings may support the notion that training for runners on harder surfaces may not be the most appropriate option for athletes with frequent foot-related overuse pathologies such as plantar fascitis and foot pain (e.g., metataralsalgia).