## 4 Discussion  
### The Effect of Timing in Each Stroke Phase  
The significant differences in stroke rate and DPS on the affected side were observed between different groups (\(p<0.01\)) and are shown in Table 2. Furthermore, a significant difference was observed in the duration of phase D, not only between S10 and S12 para swimmers (\(p<0.01\)) but also between the affected and unaffected sides with the S10 para swimmer group (\(p<0.05\)). This significant difference between the affected and unaffected sides was also seen in phase A (\(p<0.05\)). Compared to the unaffected side, the entry and catch phase (phase A) on the affected side for S10 para swimmers constituted a lower proportion of the total non-propulsive phase, namely a higher proportion in the recovery phase (phase D). On the affected side, S10 para swimmers spent 42% of cycle time on the catch phase and pull phase (phases A + D), lower than that on the unaffected side at 49%. Similar results were reported by [PERSON] et al. (2019), who found that for athletes with asymmetric strength, the ratio of the catch and pull phases on the dominant side was 51.7%, higher than the non-dominant side at 48.4%. This might imply that the disparity in strength arising from arm disabilities can exert an impact on the phase timing between left and right sides, predominantly influencing phases A and D. In this study, the affected side for S10 participants was the lack of a distal end of the upper limb (hand), which might feel weak to sense the flow of water and more challenging to find the'still water' ([PERSON] et al., 2018) for them to set up the preloading condition with the extended shoulder blade and the high elbow position before entering an efficient propulsive phase at the end of the catch phase (phase A). This inevitable diminished propulsive deficiency attributable to the absence of the distal segment is regarded as a physical constraint, which might enable S10 para swimmers to adopt a constraint-led approach that entails a decreased time allocation on catch (phase A) but an enhanced time investment on the propulsive phase and recovery phase, thereby accounting for the substantial difference in phase D between S12 para swimmers (\(p<0.01\)), as well as between the affected and unaffected side in S10 para swimmers (\(p<0.05\)) in Table 2. \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Groups**} & \multirow{2}{*}{**Phase**} & \multicolumn{2}{c}{**In-Phase**} & \multicolumn{2}{c}{**Out-Phase**} \\ \cline{3-6}  & & **Upbeat** & **Downbeat** & **Upbeat** & **Downbeat** \\ \hline \multirow{4}{*}{S10—affected-side} & Phase A ** & 0 (0.03) & 42.86 (0.01) & 0 (0.01) & 57.14 (0.02) \\  & Phase B & 28.57 & 14.29 & 28.57 & 28.57 \\  & Phase C & 28.57 & 14.29 & 28.57 & 28.57 \\  & Phase D & 14.29 & 28.57 & 14.28 & 42.86 \\ \hline \multirow{4}{*}{S10—unaffected-side} & Phase A ** & 0 (0.03) & 66.67 (0.009) & 0 (0.01) & 33.33 (0.3) \\  & Phase B & 0 & 41.67 & 25 & 33.33 \\  & Phase C & 33.33 & 0 & 33.33 & 33.33 \\  & Phase D ** & 25 (0.009) & 50 (0.009) & 0 (0.01) & 25 (0.06) \\ \hline \multirow{4}{*}{S12—left} & Phase A & 53.85 & 0 & 46.15 & 0 \\  & Phase B * & 69.23 (0.009) & 0 (0.03) & 15.38 (0.04) & 15.38 (0.04) \\  & Phase C & 7.69 & 23.07 & 69.23 & 0 \\  & Phase D ** & 76.92 (0.006) & 0 (0.03) & 15.38 (0.04) & 7.70 (0.04) \\ \hline \multirow{4}{*}{S12—right} & Phase A & 7.69 & 7.69 & 30.77 & 53.85 \\  & Phase B * & 53.85 (0.008) & 0 (0.03) & 0 & 46.15 \\ \cline{1-1}  & Phase C * & 0 (0.03) & 23.08 (0.02) & 76.92 (0.008) & 0 (0.01) \\ \cline{1-1}  & Phase D ** & 76.92 (0.006) & 0 (0.03) & 15.38 (0.04) & 7.70 (0.04) \\ \hline \end{tabular} Notes: The numbers in the table are occurrence-based percentages of certain IdIC among the corresponding side of the group. The values shown in the brackets represent the moment-corrected \(p\)-value, while the chi-square test showed a significant difference; * and ** show the significant levels 0.05 and 0.01 from the chi-square test.  
\end{table}