# Research on Kinematic Parameters of Multiple Gait Pattern Transitions
## 4 Discussion  
In general, as we expected, our results show that there are some unique gait strategies in the transition of multiple gait patterns, and there are some kinematic parameters in the transition, including the kinematic parameters of the leading limb and the trailing limb, and the kinematic parameters of the trunk in the coronal plane intuitively show the difference between the transition stride and the stride of the former gait pattern. Moreover, some parameters were adjusted and changed actively before the leading limb struck the surface of the next gait pattern. However, the parameters that have significant differences in different gait patterns are not the same, and the order that the differences occur is not the same. This is partly confirmed by the study of [PERSON] et al., who found that during the transitions between level and stair, each joint of the lower extremity (knee, hip, and ankle) exists in both transition phases, and each joint has a different order of change in the transition between level and stair, both up and down [8]. Therefore, in the application of exoskeleton gait recognition, we can identify the changes in these kinematic parameters to achieve the recognition of a variety of gait pattern transitions and even predict them in advance so that the human-exoskeleton system can timely and accurately adjust the control mode to achieve a smooth transition. * Leading limb (right)  
Overall, all relevant kinematic parameters, except the angular acceleration and the acceleration of the thigh and shank, showed significant differences in multiple transitions except for S-L UP and R-L UP (Table 2). For S-L UP, it may be because compared to the stair ascent stride, the swing trajectory of the leading limb in the transition stride between the up-stair walking and level walking basically does not change much before the leading limb strikes the surface of level (both lift two steps), and the difference mainly focuses on the difference of the trailing limb in the last two phases of the transition stride (the trailing limb only needs to lift to a one-step height) (Figure 3a); this is consistent with the work of [PERSON] et al. [17]. For R-L UP, the swing trajectory of the leading limb changes a little (Figure 3b), which is also because the height that the leading limb needs to lift to is of little difference. However, the differences of the angular acceleration of the hip, knee, and ankle of the leading limb are mostly concentrated in the first two phases in the process of S-L UP and R-L UP. Therefore, in the future, we need to focus on the angular acceleration of the hip, knee, and ankle of the leading limb for the recognition of these two kinds of gait pattern transition. During S-L DOWN and R-L DOWN, the kinematic parameters of the leading limb were significantly different. First, the angular velocity of the hip, knee, and ankle joint of the leading limb and the velocity of the thigh and shank were the significant difference parameters during S-L DOWN. In the first two phases of the gait cycle, the angular velocity of the ankle joint is significantly different (Table 8), while the angular velocity of the hip and knee joints has a larger amplitude of variation (Figure 4a). On the whole, these parameters are faster in S-L DOWN than in down-stair walking, and that is possible when people pass through a complex terrain and their gaze fixation is highly related to the terrain they are about to step on [21].Moreover, from a previous study [22], it can be seen that the peak value of the angular velocity will increase with the increase in walking speed; thus, the parameters will change as described above in order to reach the relatively safer level ground faster in the process of S-L DOWN.