## 3 Results
### Three-Way ANOVA for Joint Angle Means
#### 3.1.2 Trunk Angle  
The TA was significantly affected by the sitting strategy, the chair type, and gender, with all factors showing a \(p\)-value of less than 0.001. Post hoc comparisons revealed that the TA was largest in the comfortable sitting strategy (111.9\({}^{\circ}\)), followed by the habitual  
\begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**Variables** & **Joint Angles** & **df** & **SS** & **MS** & **F** & \(p\)**-Value** & **Power** \\ \hline \multirow{4}{*}{Strategy (S)} & Head inclination & 2 & 251 & 126 & 1.40 & 0.250 & 0.298 \\  & Trunk angle & 2 & 1649 & 824 & 11.15 & \textless{}0.001 & 0.992 \\  & Knee angle & 2 & 1421 & 711 & 7.08 & \textless{}0.01 & 0.928 \\ \hline \multirow{4}{*}{Chair type (C)} & Head inclination & 2 & 6931 & 3466 & 38.44 & \textless{}0.001 & 1.000 \\  & Trunk angle & 2 & 24,482 & 12,241 & 165.63 & \textless{}0.001 & 1.000 \\  & Knee angle & 2 & 135 & 67 & 0.67 & 0.512 & 0.162 \\ \hline \multirow{4}{*}{Gender (G)} & Head inclination & 1 & 21 & 21 & 0.23 & 0.631 & 0.077 \\  & Trunk angle & 1 & 1857 & 1857 & 25.12 & \textless{}0.001 & 0.999 \\  & Knee angle & 1 & 1863 & 1863 & 18.54 & \textless{}0.001 & 0.990 \\ \hline \multirow{4}{*}{S\(\times\)C} & Head inclination & 4 & 135 & 34 & 0.38 & 0.826 & 0.136 \\  & Trunk angle & 4 & 2278 & 569 & 7.71 & \textless{}0.001 & 0.997 \\  & Knee angle & 4 & 148 & 37 & 0.37 & 0.831 & 0.134 \\ \hline \multirow{4}{*}{S\(\times\)G} & Head inclination & 2 & 20 & 10 & 0.11 & 0.893 & 0.067 \\  & Trunk angle & 2 & 38 & 19 & 0.26 & 0.771 & 0.091 \\  & Knee angle & 2 & 8 & 4 & 0.04 & 0.963 & 0.056 \\ \hline \multirow{4}{*}{C\(\times\)G} & Head inclination & 2 & 141 & 71 & 0.78 & 0.459 & 0.183 \\  & Trunk angle & 2 & 748 & 374 & 5.06 & \textless{}0.01 & 0.816 \\  & Knee angle & 2 & 379 & 189 & 1.89 & 0.154 & 0.390 \\ \hline \multirow{4}{*}{S\(\times\)C\(\times\)G} & Head inclination & 4 & 88 & 22 & 0.24 & 0.914 & 0.103 \\  & Trunk angle & 4 & 73 & 18 & 0.25 & 0.912 & 0.103 \\ \cline{1-1}  & Knee angle & 4 & 279 & 70 & 0.70 & 0.596 & 0.224 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Three-way ANOVA results of the mean angle.  
\begin{table}
\begin{tabular}{l l l} \hline \hline  & **Head Inclination (\({}^{\circ}\))** & **Trunk Angle (\({}^{\circ}\))** & **Knee Angle (\({}^{\circ}\))** \\ \hline Chair type & & & \\ Stool & 165.3 (9.1) A & 97.9 (9.6) A & 97.7 (12.6) A \\ Computer chair & 158.2 (9.4) B & 108.2 (10.2) B & 95.9 (10.1) A \\ Ergonomic chair & 153.0 (9.6) C & 121.2 (9.3) C & 96.7 (8.4) A \\ \hline Strategy & & & \\ Correct & 160.0 (9.5) A & 105.9 (8.5) A & 93.8 (7.3) A \\ Habitual & 158.8 (11.4) A & 109.5 (14.9) AB & 97.1 (12.2) B \\ Comfortable & 157.7 (10.8) A & 111.9 (15.7) B & 99.4 (10.7) B \\ \hline \hline \end{tabular}
\end{table}
Table 2: Duncan test results of the mean angles under different chair types and sitting strategies.  
strategy (99.4\({}^{\circ}\)), followed by the habitual sitting strategy (97.1\({}^{\circ}\)), and lowest in the correct sitting strategy (93.8\({}^{\circ}\)) (Table 2). Gender differences were also observed, with women demonstrating a greater KA (99.5\({}^{\circ}\)) compared to men (94.1\({}^{\circ}\)).