## 4 Discussion
Phase 2 is a major braking phase that reduces gait velocity by 60-70% and includes the terminal swing of the leading limb [36]. Previous studies have emphasized the importance of rapid variability in ankle joints and control of plantar flexion moment for generating braking force [37; 38]. Our results were consistent with those of a previous study, which showed greater ankle ROM during both PGT and UGT, compared to walking [4; 39]. In addition, greater knee ROM was observed in UGT than in the PGT [4]. Previous studies have reported that the hip and knee strategy that absorbs forces and controls the movementof the COM is preferred to complete gait termination safely and quickly in response to an unexpected stimulus. Greater hip and knee flexion allow subjects to increase the braking force faster to reach a COM stop [25; 32; 40]. Previous findings suggest that hip and knee kinematic information is the primary variable of interest in gait termination [4; 25]. However, in our results, a lower hip ROM was observed during PGT than during walking, which is thought to be associated with a shorter step length in PGT because the gait velocity was similar between the three conditions. In addition, step length positively correlated with hip ROM [41]. For example, during the PGT trial, most subjects landed posteriorly in both walking and UGT foot positions, resulting in shorter step lengths. Perhaps subjects in the PGT trial prepared for deceleration by relying on the ankle joint rather than the hip and knee joints to absorb force and control the COM motion in the terminal swing. In Phase 3, differences in joint motion between PGT and UGT were investigated to elucidate the mechanisms underlying body stability during gait termination. The results showed that the UGT trial exhibited a significantly lower hip ROM and significantly greater knee ROM than the PGT trial. The COM during UGT is moved backward to stretch the hip joint, and knee flexion is increased to stably convert forward inertia [8]. However, ankle ROM did not show a statistically significant difference between the PGT and UGT trials. This may be because the body primarily focuses on stabilization and the ankle joint is not actively involved in generating the braking force. These findings suggest that during PGT, gait can be terminated while gradually maintaining the stability of the whole body through external rotation of the hip joint and slight flexion of the knee joint [32; 42; 43]. From the perspective of ground reaction forces (GRF) occurring in Phase 3, when an individual suddenly stops their gait (i.e., during UGT), both vertical and anteroposterior (A-P) GRF increase abruptly. This is because of the need to counter the body's forward momentum, which generates significant rearward stimuli [40; 44]. In addition, the vertical impulse increases to provide support to the body during deceleration [45]. The magnitude of the GRF varies according to an individual's velocity, mass, deceleration duration, and extent [45]. In this study, we observed no significant differences in the velocity and mass of the subjects, implying that the differences in the GRF magnitude arise from the characteristics of the push-off and unloading phases of gait. Our findings suggest that the unloading phase can rapidly adjust the GRF to counteract forward momentum and maintain equilibrium. This study has several limitations. First, the study was conducted on healthy young adults; therefore, the findings may not be generalizable to other populations with gait impairment. Second, the study only focused on spatiotemporal, kinematic, and kinetic parameters and did not consider other factors that may affect gait termination, such as cognitive and neurological factors. In addition, the study only investigated gait termination on level ground and did not consider gait termination on inclines or declines. Finally, this study only investigated gait termination at one designated force plate during PGT, which may limit the generalizability of the findings to other stopping locations.