## 3 Results  
### Analysis of the Magnitude in Terms of Area Changes  
Participants exhibited various stepping strategies in response to the studied perturbations, which were triggered during the IC, MS, and PS phases of the gait cycle by accelerating the left treadmill lane (Figure 4), leading to changes in gait cycle length and both kinematic and kinetic parameter values (Table 1, Figure 6). When studying the comparison of the curves for ankle angles with perturbation in the IC phase (Figure 6A) and the curve without perturbation, it is noteworthy that statistically significant differences not only occur at the moment of perturbation but also extend to a  
Figure 6: The means and standard deviations of curves across all individuals for the (**A**) ankle angle joint, (**B**) knee angle joint, (**C**) hip angle joint, (**D**) ankle torque, (**E**) knee torque, and (**F**) hip torque throughout the gait cycle. The first column shows the curves for the affected limb without perturbation (black), with perturbation in the Initial Contact (red), Mid Stance (green) and Pre-Swing (blue) phase of gait cycle. The second, third, and fourth columns display the post hoc analysis, with critical threshold (**t***) values located on the right axis. Highlighted areas indicate ranges where statistically significant differences exist compared to gait without perturbation, where df—dorsiflexion, pf—plantarflexion, flex—flexion, and ext—extension. significantly larger area, as follows: [0-34.6]%, [39.18-64.38]%, and [70.42-88]% of the gait cycle. For the knee angle (Figure 6B), differences manifest in two clusters: [10.62-72.96]% and [90-100]% of the gait cycle. However, for the hip joint (Figure 6C), the differences cover the entire swing phase and part of the support phase, starting from the beginning of the Terminal Stance phase [39-100]% of the gait cycle. Similarly, when examining the behaviour of ankle torque (Figure 6D), it is worth noting that statistically significant differences occur in shifted areas compared to those observed for kinematic parameters. These differences manifest as follows: [5-36]%, [46.74-69.29]%, and [92.11-96.85]% of the gait cycle. For the knee joint (Figure 6E), differences are recorded across almost the entire gait cycle, presenting in six clusters: [0-4]%, [7-35.4]%, [45.6-56.3]%, [60-67]%, [72-74.36]%, and [91.6-95]% of the gait cycle. However, in the case of the hip joint (Figure 6F), differences include the following areas: [0-4]%, [52.6-67]%, and [97-100]% of the gait cycle. In particular, an additional area of [0-4]% appeared for the knee and hip torque, which was not observed for the angles. When comparing the curves for the ankle joint angle with perturbation in the MS phase (Figure 6A) to the curve for gait without perturbation, three areas exhibit statistically significant differences: [0-9]%, [43-67]%, and [81-92]% of the gait cycle. Similar to previous findings, differences are observed for additional joints but are confined to two clusters: [5-60]% and [93-100]% of the gait cycle for the knee joint (Figure 6B) and [34-46]% and [51-60]% of the gait cycle for the hip joint (Figure 6C). Similar to the previous perturbation, the analysis of muscle torques provides different information. When comparing the curves for ankle torque with perturbation in the Mid Stance phase (Figure 6D) to the curves for gait without perturbation, three areas, similar to those observed for angles, exhibit statistically significant differences: [23.47-51.17]%, [57.81-59.22]%, and [92.36-98]% of the gait cycle. In the knee joint (Figure 6E), differences are evident throughout the entire gait cycle, with as many as six clusters: [2-4.22]%, [6.63-20]%, [31.31-37.02]%, [52-59]%, [62-69]%, and [85.5-93]% of the gait cycle. However, for the hip joint (Figure 6F), differences manifest in two clusters: [6-62-21]% and [62.77-85.80]% of the gait cycle. Most differences were observed for curves containing perturbations during the Pre-Swing phase.