## 4 Discussion
Although some of the studies mentioned only collected spatiotemporal parameters, others [38; 39; 40; 41] suggested that including kinematics and kinetic data in the outcome variables could add depth to the results or provide an alternative perspective. Based on this data, this paper offers a comprehensive study of the musculoskeletal responses to perturbations resulting from tripping just before the swing phase, covering the spatiotemporal, kinematic, and kinetic parameters. In response to the sudden belt deceleration, there was a significant increase in the stride length, the stance phase, and their timing. Furthermore, it led to changes in the joint angles and muscle torques, as demonstrated in Figure 5, showing the musculoskeletal system's aggressive response, equivalent to the execution of a lunge squat. When comparing the kinematic and kinetic data in Table 3 to findings from previous studies on the lunge squat [42; 43; 44], significant similarities were evident, particularly at the hip joint. [PERSON], et al. [43] investigated the effects of fatigue on lower limb biomechanics during the anterior lunge, both before and after completing a fatigue protocol. The authors demonstrated a significant increase in the maximum hip-angle peak after fatigue (from 88.51\({}^{\circ}\)\(\pm\) 12.36\({}^{\circ}\) to 92.89\({}^{\circ}\)\(\pm\) 9.23\({}^{\circ}\)). Interestingly, our research found that the perturbation had a profound impact on the hip joint angles, with recorded values of 60.39\({}^{\circ}\)\(\pm\) 9.35\({}^{\circ}\) for the affected limb and 68.31\({}^{\circ}\)\(\pm\) 6.39\({}^{\circ}\) for the responding limb, respectively. These similarities highlight the significant effect of the perturbation on the hip joint angles. The knee and ankle joint angles varied, primarily due to the authors' predetermined and strictly controlled squat technique, which involved, among other things, a step length set at 70% of the leg length. Such controlled conditions were not present in the perturbation response. [PERSON], et al. [44] conducted an in-depth analysis of how changes in the shank angle and trunk position influence the biomechanics of the lead and trail limbs during a forward lunge exercise. Their study revealed that adopting a forward trunk and shank position resulted in the greatest patelltoemoral stress on the lead limb. Conversely, a lunge variation with a vertical shank position caused significantly higher peak patelltoemoral joint stress in the trailing limb compared to the lead limb. These findings highlight the critical role of trunk and shank positioning in determining patelltoemoral joint loading, with the trailing limb generally bearing higher overall joint stress. This aligns with the present study, which observed a similar increase in the hip-extensor muscle torque during perturbations, particularly in the affected limb. Additionally, the current findings are consistent with [PERSON], et al. [45], who demonstrated that performing a forward lunge with a forward trunk position enhances hip extensor recruitment. Such a result is also presented in this paper, where the values of muscle torque for the hip extensors were highest for the perturbed limb, at 2.14 \(\pm\) 0.37 Nm/kg, surpassing those recorded for the unperturbed gait more than threefold. The study's utilization of the induced deceleration technique may have noteworthy implications for gait rehabilitation because it challenges and improves the individual's ability to adapt to unexpected changes in the walking environment. It can help identify gait abnormalities, balance deficits, and asymmetries in gait and aid in designing targeted interventions to improve gait stability and control. Moreover, from a clinical perspective, the implications of these findings can be particularly relevant to the aging population, where reduced joint flexibility and muscle strength are common and contribute to an increased risk of falls [46, 47].