## 3 Results
### Effects of Instability Level and Sensory Information on Movement Characteristics
#### 3.2.2 Chest Movement 95 th CI Ellipsoid Volume  
The data of 95 th CI ellipsoid volume, across different SIS and ILs, are outlined in Table 3.  
Figure 3: The general trend in how the chest movement velocity (cm/s) changes at different ILs and SIS. Black-filled \(\lozenge\) symbols indicate outliers, deviating from the central range.  
Figure 2: A comparison of velocity (cm/s) of different instability levels (ILs) under different sensory integration strategies (SIS). Lines on top with \(\star\) represent pairs that have statistical significance; lines on top with \(\blacktriangle\) represent pairs where we did not find statistical significance. Black-filled \(\lozenge\) symbols indicate outliers, deviating from the central range.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**IL**} & \multirow{2}{*}{**SIS**} & \multicolumn{2}{c}{**0 IL**} & \multicolumn{2}{c}{**1 IL**} & \multicolumn{2}{c}{**2 IL**} & \multicolumn{2}{c}{**3 IL**} \\ \cline{2-10}  & & **Median** & **IQR** & **Median** & **IQR** & **Median** & **IQR** & **Median** & **IQR** \\ \hline
**Basic** & 179.5 & 261.7 & 561.5 & 551.8 & 771.6 & 833.6 & 692.9 & 855.7 \\ \hline
**Visual** & 186.1 & 188.7 & 653.5 & 683.6 & 3213.8 & 7806.3 & 2645.0 & 3163.6 \\ \hline
**Proprioception** & 855.7 & 726.5 & 1354.4 & 1117.9 & 1725.0 & 1389.9 & 1784.7 & 2104.5 \\ \hline
**Vestibular** & 1880.0 & 1633.2 & 4604.4 & 6535.5 & 9729.0 & 12,599.6 & 12,917.0 & 23,512.2 \\ \hline \hline \end{tabular}
\end{table}
Table 3: A comparison of 95 th CI Ellipsoid Volume (cm\({}^{3}\)) of different instability levels (ILs) under different sensory integration strategies (SIS) with median values and color scale (green: lower, yellow: moderate, red: higher).  
In the Basic strategy, chest volume increases from 179 cm\({}^{3}\) at 0 IL to 692 cm\({}^{3}\) at 3 IL, reflecting a 386% increase. The Vestibular strategy shows a more substantial change in chest volume, from approximately 1880 cm\({}^{3}\) at 0 IL to about 12,917 cm\({}^{3}\) at 3 IL, representing a significant 687% increase.  
Comparing the volume between Basic 0 IL and Vestibular 0 IL, there is a considerable increase of about 1050%. However, the volume increase between Basic 3 IL and Vestibular 3 IL is even more drastic at 2750%.  
When comparing chest volume between Basic 0 IL and Vestibular 3 IL, we observe a remarkable increase of 7176%.  
Figures 4-6 represent these changes. Figure 4 presents the comparison of the 95 th CI ellipsoid volume across different ILs under various SIS. Figure 5 portrays the general trend in how the 95 th CI ellipsoid volume changes with different ILs and SIS. Meanwhile, Figure 6 illustrates a participant's chest movement and 95 th CI ellipsoid volume under different combinations of IL and SIS.  
Figure 4: Comparison 95 th CI ellipsoid volume (cm\({}^{3}\)) of different instability levels (ILs) under different sensory integration strategies (SIS). Lines on top with \(\bigstar\) represent pairs that have statistical significance; lines on top with \(\blacktriangle\) represent pairs where we did not find statistical significance. Black-filled \(\lozenge\) symbols indicate outliers, deviating from the central range.  
Figure 5: The general trend in how the chest movement 95 th CI ellipsoid volume (cm\({}^{3}\)) changes at different instability levels (ILs) under different sensory integration strategies (SIS). Black-filled \(\lozenge\) symbols indicate outliers, deviating from the central range.