## 3 Results
### Trunk Muscle Activity  
Differences in trunk muscle activities between the DS and NDS are presented in Figure 4. In NPT, there were significant differences in the activities of EST, ESL, and MF muscle between the DS and NDS before performing the exercise (\(p<0.05\) and \(p<0.01\)). After performing the exercise, the activity of EST, ESL, and MF muscle on the DS all decreased by 8.7%, 11.5%, and 4.7% while that on the NDS all increased by 9.0%, 12.3%, 26.3%, respectively. However, there were no significant differences in muscle activities between before and after performing the exercise both for the DS and NDS. In dynamic sitting conditions, the overall tendency in the activity of all muscles was increased both for the DS and NDS after performing the exercise. Especially, the activities of all muscles increased more on the NDS than the DS. In LPT, there were significant differences in the activities of EST and ESL muscle except MF muscle between the DS and NDS before performing the exercise (\(p<0.05\) and \(p<0.01\)). After performing the exercise, on the DS, the activity of EST, ESL, and MF muscle all increased by 32.7%, 21.6%, and 17.9%, respectively. However, a significant difference was only shown in the activity of EST muscle (\(p<0.01\)). In contrast, on the NDS, the activities of all muscles increased significantly by 86.5%, 67.3%, 33.2%, respectively (\(p<0.01\) and \(p<0.05\)). In APT, the significant differences in muscle activity between the DS and NDS were shown in all muscles before performing the exercise (\(p<0.05\) and \(p<0.01\)). After performing the exercise, on the DS, the activity of EST and MF muscle increased by 12.3% and 7.7% while the activity of ESL muscle decreased by 0.5%. There were no significant differences in the muscle activity of all muscles between before and after performing the exercise. On the contrast, on the NDS, the activities of all muscles increased significantly by 54.3%, 50.6%, and 46.7%, respectively (\(p<0.01\) and \(p<0.05\)). In PPT, before performing the exercise, the significant differences in muscle activity between \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{4}{c}{**Experimental Conditions**} & \multicolumn{6}{c}{**Body Pressure Distribution**} \\ \hline \multirow{4}{*}{Static} & \multirow{2}{*}{NPT} & \multicolumn{2}{c}{DS} & NDS & \(p\)\({}^{\text{a}}\) & \(p\)\({}^{\text{b}}\) & \(p\)\({}^{\text{c}}\) \\ \cline{3-8}  & & & BF & 144.6 \(\pm\) 38.3 & 113.1 \(\pm\) 34.2 & 0.001 & \\ \cline{3-8}  & & & AF & 121.6 \(\pm\) 31.9 & 106.5 \(\pm\) 28.2 & 0.056 & \\ \cline{3-8}  & & & BF & 297.7 \(\pm\) 45.8 & 228.4 \(\pm\) 46.2 & 0.000 & \\ \cline{3-8}  & & & AF & 274.0 \(\pm\) 39.3 & 259.5 \(\pm\) 44.8 & 0.188 & \\ \cline{3-8}  & & & BF & 235.4 \(\pm\) 43.7 & 177.4 \(\pm\) 41.7 & 0.000 & \\ \cline{3-8}  & & & AF & 210.2 \(\pm\) 40.9 & 201.8 \(\pm\) 37.2 & 0.404 & \\ \cline{3-8}  & & & BF & 236.7 \(\pm\) 37.1 & 167.9 \(\pm\) 39.1 & 0.000 & \\ \cline{3-8}  & & & AF & 215.1 \(\pm\) 40.7 & 199.2 \(\pm\) 37.0 & 0.121 & \\ \cline{3-8}  & & & BF & 4.1 \(\pm\) 0.9 & 3.4 \(\pm\) 1.0 & 0.006 & \\ \cline{3-8}  & & & AF & 3.8 \(\pm\) 1.0 & 3.5 \(\pm\) 1.2 & 0.254 & \\ \cline{3-8}  & & & BF & 7.7 \(\pm\) 1.4 & 5.8 \(\pm\) 1.3 & 0.000 & \\ \cline{3-8} Mean pressure (kPa) & & & AF & 7.4 \(\pm\) 1.3 & 7.0 \(\pm\) 1.4 & 0.254 & \\ \cline{3-8}  & & & BF & 6.0 \(\pm\) 1.1 & 4.5 \(\pm\) 1.2 & 0.000 & \\ \cline{3-8}  & & & AF & 5.6 \(\pm\) 1.1 & 5.4 \(\pm\) 1.1 & 0.463 & \\ \cline{3-8}  & & & BF & 6.1 \(\pm\) 1.0 & 4.3 \(\pm\) 1.0 & 0.000 & \\ \cline{3-8}  & & & AF & 5.8 \(\pm\) 1.2 & 5.4 \(\pm\) 1.1 & 0.158 & 0.282 & 0.000 \\ \hline \multicolumn{8}{l}{Notes: (M \(\pm\) SD); \({}^{\text{a}}\): Independent samples t-test: dominant side vs. non-dominant side; \({}^{\text{b}}\): Paired t-test on the dominant side between before and after exercise; \({}^{\text{c}}\): Paired t-test on the non-dominant side between before and after exercise.} \\ \end{tabular}
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