# Effects of a Dual-Task Paradigm and Gait Velocity on Dynamic Gait Stability during Stair Descent
## 4 Discussion
Our results agree with some previous studies [12; 13] indicating integration between attentional resources. It is worth mentioning that one study with similar results speculated that the constraint imposed by the more demanding dual-task condition interplayed with the original gait task (stair descent), leading to improved body stability [13]. Further evidence for this conceptualization has been provided through neurophysiological measurements demonstrating increased activation of the supplementary motor area and primary sensorimotor areas during a dual-task condition [39]. Activities of the supplementary motor area and the primary sensorimotor areas during the dual-tasks employed here need to be investigated in future projects. Since improved body stability is a prerequisite for stable maintenance of glass-holding, it is plausible that the performance of the original task also benefited [13]. These results have been interpreted to be a consequence of the functional integration of postural control with a dual-task paradigm. To be specific, the functional integration between gait and MT is implemented as the control of not two independent units but a single unit in a coordinated task. This conceptualization could also help explain why MT was related to DGS but not CT. Since MT and gait are both motor-related tasks, they may be easily integrated as a single unit, while the integration of a cognitive task and a gait task as in CT may be much more difficult. The possibility worth mentioning here is that a cautious gait strategy could have been employed to avoid spilling water rather than to prevent a fall. The authors recommended that future studies concerning the dual-task paradigm should consider the gait velocity and differentiate the effects of MT and CT, since they may differently influence the concurrent task. This study was conducted with a group of young females for proof of concept. Future studies should focus on the elderly population since they experience more falls [40] and require more attentional resources during stair ambulation [41] compared to their younger counterparts. This study has several limitations. Firstly, it would be a good option if we could measure the DGS in different gait velocities (like normal and fast) since this work aimed to examine the effects of gait velocity on DGS during stair descent. However, it would be difficult for the participants to maintain a fast gait velocity when they were asked to perform a concurrent cognitive task. There would be an apparent decrease in gait velocity when they started to calculate a new subtraction, which would influence their gait during stair descent. Secondly, we used IA to represent DGS. Other potential indicators, such as the largest Lyapunov exponent or margin of stability, could also be considered for evaluating DGS during gait descent. It is important to mention that IA is one of many possibilities. Lastly, the participants carried a glass with 350 ml of water for MT. They had to use a cautious gait strategy and improve their DGS to avoid spilling water rather than to prevent a fall. Perhaps carrying a box or a tray might be a better option.