## 4 Discussion  
Maintaining balance in both static and dynamic conditions involves a complex interplay between biomechanical, neurological, and environmental factors. Despite previous studies reporting different setups of foot placement for the assessment of postural stability, no agreement or recommendations have been reached on the optimal and most reliable foot position yet [29, 30], particularly, in terms of executing the exam with the recommended visual target distance [5]. This study aimed to assess the effect of self-selected comfortable (SCFP) and standardized foot position (SFP) on changes in stabilometric and plantar pressure parameters and on their variability during viewing a target, placed at 0.7 m from the subjects' heels. In terms of foot position, subjects showed no significant differences between the right foot standing angle (RFSA) and left foot standing angle (LFSA). There was a significant lower between-feet angle (BFA) and greater Inter-Heels Distances (IHMD and IHPD) in SCFP compared to SFP. Our findings seem to suggest that healthy subjects, when allowed to self-select a comfortable foot position, tend to place their feet nearly parallel and symmetrically aligned with respect to the midline and with a wider inter-heels distance, \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Plantar Pressure and**} & \multirow{2}{*}{**LS**} & **SCFP (A)** & **SFP (B)** & **SCFP vs. SFP (A vs. B)** \\ \cline{3-5}  & & & **Median (25 th–75 th Percentiles)** & _p-Value_ \\ \hline \multirow{3}{*}{Pmean Ff [KPa]} & 1 & 25.7 (22.1; 27.8) & 26.5 (23.5; 29.8) & 0.339 \\ \cline{2-5}  & r & 31.2 (30.3; 33.8) & 31.5 (28.0; 33.8) & 0.322 \\ \hline \multirow{3}{*}{Pmax Tf [KPa]} & 1 & 93.0 (80.7; 102.0) & 91.9 (81.7; 106.0) & 0.681 \\ \cline{2-5}  & r & 91.3 (73.3; 106.7) & 92.0 (84.0; 102.3) & 0.896 \\ \hline \multirow{3}{*}{Pmax Rf [KPa]} & 1 & 93.0 (80.7; 102.0) & 91.9 (81.7; 106.0) & 0.681 \\ \cline{2-5}  & r & 91.2 (72.7; 106.7) & 92.0 (84.0; 102.3) & 0.896 \\ \hline \multirow{3}{*}{Pmax Mf [KPa]} & 1 & 39.4 (30.7; 50.3) & 42.1 (30.7; 53.0) & **0.044 (B)** \\ \cline{2-5}  & r & 39.9 (27.7; 50.3) & 41.5 (32.7; 53.7) & 0.198 \\ \hline \multirow{3}{*}{Pmax Ff [KPa]} & 1 & 42.9 (36.3; 48.3) & 44.1 (35.0; 54.3) & 0.339 \\ \cline{2-5}  & r & 53.9 (49.7; 57.7) & 56.2 (49.0; 60.3) & 0.054 \\ \hline \multirow{3}{*}{FCA [mm\({}^{2}\)]} & 1 & 94.4 (82.0; 108.6) & 91.9 (77.7; 104.0) & 0.149 \\ \cline{2-5}  & r & 108.3 (90.7; 127.7) & 103.3 (91.3; 121.6) & **0.032 (A)** \\ \hline \multirow{3}{*}{AI [\%]} & 1 & 11.3 (4.8; 14.4) & 11.9 (4.2; 16.9) & 0.394 \\ \cline{2-5}  & r & 13.3 (5.9; 19.1) & 12.5 (4.1; 18.4) & 0.289 \\ \hline CoPsa [mm\({}^{2}\)] & & 38.1 (28.8; 47.9) & 38.2 (26.1; 51.0) & 0.931 \\ \hline CP speed [mm/s] & & 4.8 (4.2; 5.2) & 4.4 (3.5; 4.2) & **0.001 (A)** \\ \hline LSF [mm\({}^{-1}\)] & & 4.7 (4.2; 7.7) & 4.7 (2.6; 6.3) & 0.085 \\ \hline \hline \end{tabular} Note: Each condition is identified as follows: SCFP (A) and SFP (B). The letter in bold indicates the condition in which the significant increase was found. Limb side (LS); left (L); right (R); total foot (Tf); rearfoot (Rf); midfoot (Mf); forefoot (Ff); mean pressure (Pmean); maximum pressure (Pmax); foot contact area (FCA); arch index (AI); center of pressure (CoP); center-of-pressure sway area (CoPsa); center of pressure speed (CP speed); length surface function (LSF); self-selected comfortable foot position (SCFP); standardized foot position (SFP).  
\end{table} 
Table 4: _Cont._increasing the contact area between the feet (feet support surface) (Figure 1). This is in spite of a previous study [15] reporting a significant inter-subject variability in the positioning of the feet when subjects' behavior is not constrained.