## 3 Results
### Kinematic Analysis
#### 3.2.2 Non-Linear Analysis
For the hip, MSE measures were significantly lower in the stroke group, with reductions observed for POS (S1: \(p\) = 0.023; S2: \(p\) = 0.009; CI: \(p\) = 0.040) and DISP (S1: \(p\) = 0.034; S2: \(p\) = 0.040; CI: \(p\) = 0.034) in the swing limb. For the knee, LyE values for DISP in the healthy group were positive in both limbs, indicating divergence, while the stroke group exhibited negative LyE values in the swing limb, reflecting convergence, and positive values in the stance limb, though these differences were not statistically significant (\(p\) > 0.05). For the ankle, the healthy group demonstrated divergence in DISP with positive LyE values in both limbs, while the stroke group exhibited convergence with negative LyE values, which were significant for both limbs (\(p\) = 0.021 and \(p\) = 0.002, respectively). MSE measures for the ankle were significantly reduced in the stroke group, with reductions observed for POS in the swing limb (S2: \(p\) = 0.001; CI: \(p\) < 0.001) and stance limb (S1: \(p\) = 0.008; CI: \(p\) < 0.001), as well as for MDISP in the swing limb (S1: \(p\) = 0.012; S2: \(p\) = 0.021; CI: \(p\) = 0.011) (Figures 8 and 9). In the transverse plane, the stroke group showed reduced convergence in POS for LyE values. For the hip, significant differences were observed in the swing limb (\(p\) = 0.006), while for DISP, LyE values were predominantly negative (convergence) in the stroke group, except in the stance limb, where they remained positive. MSE measures for the hip showed significant reductions in POS (CI: \(p\) = 0.040) and DISP (CI: \(p\) = 0.034) in the swing limb. For the knee, LyE values for DISP were positive (divergence) in the healthy group but were predominantly negative (convergence) in the stroke group, with significant differences observed in the stance limb (\(p\) = 0.009). For the ankle, POS LyE values showed significant differences in both swing (\(p\) = 0.013) and stance (\(p\) < 0.001) limbs. For DISP, LyE values were predominantly negative in the stroke group, with significant differences in the stance limb (\(p\) = 0.031). MSE measures for the ankle showed significant reductions in the stroke group, with decreased POS values in the stance limb (S1: \(p\) = 0.016; S2: \(p\) < 0.001; CI: \(p\) < 0.001) and DISP values also being significantly reduced in the stance limb (S1: \(p\) = 0.023; CI: \(p\) = 0.040) (Figures 8 and 9). Upper Limb Joints  
In the sagittal plane, the stroke group exhibited significantly reduced convergence for DISP in the shoulder (\(p\) = 0.011), along with MSE reductions in the swing limb (S1: \(p\) = 0.002; S2: \(p\) = 0.003; CI: \(p\) = 0.002). For the elbow, DISP also showed a significant reduction in convergence in the swing limb (\(p\) = 0.034). For the wrist, DISP LyE values were positive (indicating divergence) in the stance limb for both groups, whereas in the swing limb, LyE values were divergent in the stroke group and convergent in the healthy group, with a significant difference (\(p\) = 0.012). Additionally, MSE measures showed significant reductions for POS in the wrist swing limb (CI: \(p\) = 0.014) (Figures 10 and 11). Figure 8: Non-linear analysis of position and mean displacement of swing lower limb joints. H: healthy; S: stroke; LyE, largest Lyapunov exponent; S1: Multiscale Entropy Scale 1; S2: Multiscale Entropy Scale 2; CI, Multiscale Entropy Complexity Index; EXT, extension; FLE, flexion; AD, adduction; ABD, abduction; IR, internal rotation: ER, external rotation; DF, dorsiflexion; PF, plantar flexion; IN, inversion; EV, version; * _p_-value < 0.05: Mann–Whitney test. Figure 9: Non-linear analysis of position and mean displacement of stance lower limb joints. H: healthy; S: stroke; LyE, largest Lyapunov exponent; S1: Multiscale Entropy Scale 1; S2: Multiscale Entropy Scale 2; CI, Multiscale Entropy Complexity Index; EXT, extension; FLE, flexion; AD, adduction; ABD, abduction; IR, internal rotation: ER, external rotation; DF, dorsiflexion; PF, plantar flexion; IN, inversion; EV, version; * _p_-value < 0.05: Mann–Whitney test.