## 3 Results  
Descriptive plantar pressure data for all registered steps are shown in Table 1. A total of 194 and 207 steps were registered for the CS and MS conditions, respectively. For both conditions, the foot contact of most of the steps was the midfoot. However, the proportion of forefoot contacts with MS was higher than for CS (21 vs. 9%).  
Table 2 shows the results of the mixed models obtained. Although condition did not show a significant main effect for any of the variables (\(p>0.05\)), its interaction with time was significant for peak pressure (ES = 0.7), contact time (ES = 0.2) and contact area (ES = 0.5). In this sense, in this interaction, the differences between conditions were greater at the end of the run, with the minimalist shoe presenting a higher peak pressure (CI: 0.79, 5.35; \(p\) = 0.008), a shorter contact time (CI: \(-7.48\), \(-1.42\); \(p\) = 0.004), and a smaller contact area (CI: \(-2.26\), \(-0.86\); \(p<0.001\)). The interaction of the condition with the foot strike pattern was also significant for mean pressure, peak pressure, contact time, relative force and contact area, with the forefoot showing the greatest differences between the two conditions (mean pressure CI: \(-46.39\), \(-19.49\); \(p<0.001\) ES = 1.3, peak pressure CI: \(-52.33\), \(-17.63\); \(p<0.001\) ES = 1.4, contact time CI: 18.26, 64.79; \(p=0.001\) ES = 0.8, contact area CI: 7.27, 17.86; \(p<0.001\) ES = 0.9), except in the case of relative force which occurred in the rearfoot (CI: \(-15.01\), \(-2.21\); \(p=0.009\) ES = 0.7). Regarding the rest of the independent variables, a main effect of the foot strike pattern was observed, with a forefoot pattern resulting in a lower mean pressure (CI: 4.87, 30.00; \(p=0.007\) ES = 0.0 for midfoot, and CI: 7.42, 41.84; \(p=0.005\) ES = 0.1 for rearfoot), a lower peak pressure (CI: 4.26, 36.82; \(p=0.014\) ES = 0.1  
for midfoot, and CI: 13.87, 58.52; \(p=0.02\) ES = 0.3 for rearfoot), a higher contact time with respect to midfoot pattern (CI: \(-\)55.28, \(-\)12.29; \(p=0.002\) ES = 03), and a higher contact area with respect to rearfoot pattern (CI: \(-\)13.85, \(-\)0.09; \(p=0.047\) ES = 0.2). A main effect of time was also observed, showing that the longer the time, the lower the peak pressure and the larger the contact area. Figure 1 shows the predictions of the condition effect and its interaction with time and foot strike pattern for each of the variables.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Characteristic** & **CS, \(n=194\)1** & **95\% CI 2** & **MS, \(n=207\)1** & **95\% CI 2** \\ \hline Foot contact & & & & \\ Forefoot & 18 (9.3\%) & 5.7\%, 14\% & 43 (21\%) & 16\%, 27\% \\ Midfoot & 151 (78\%) & 71\%, 83\% & 140 (68\%) & 61\%, 74\% \\ Rearfoot & 25 (13\%) & 8.7\%, 19\% & 24 (12\%) & 7.7\%, 17\% \\ Predominant pattern & 153 (79\%) & 72\%, 84\% & 167 (81\%) & 74\%, 86\% \\ Mean pressure (Kpa) & 79 (26) & 75, 83 & 84 (34) & 79, 88 \\ Peak pressure (Kpa) & 156 (37) & 150, 161 & 173 (46) & 166, 179 \\ Contact time (ms) & 195 (46) & 188, 201 & 195 (48) & 188, 201 \\ \({}^{3}\) CoP velocity (m/s) & 0.20 (0.10) & 0.19, 0.22 & 0.18 (0.09) & 0.17, 0.19 \\ Relative force (\%) & 58 (9) & 57, 59 & 56 (9) & 54, 57 \\ Contact area (cm\({}^{2}\)) & 60 (14) & 58, 62 & 56 (18) & 53, 58 \\ \hline \hline \end{tabular}  
* \(n\) (%); mean (SD); 2 CI = confidence interval; 3 CoP = center of pressure.  
\end{table}
Table 1: Descriptive data all registered steps in pressure platform variables for both conditions assessed: running with conventional shoes (CS) and running with minimalist shoes (MS).  
Figure 1: Predictions (lines), on the data obtained (points), of the condition effect and its interaction with time and foot strike pattern for each of the plantar pressure variables. CoP = center of pressure.