| خلاصه مقاله | Background and Aim : Knowledge about Inter-segmental coordination (ISC) during challenging walking conditions provides insight into the adaptability of central nervous system for controlling human gait. The aim of this study was to assess the effects of cognitive load and speed on the variability and phase dynamics of ISC during walking.
Methods : We asked thirty healthy young, twenty non-faller and ten faller people to participate in this study. They performed 9 walking trials on a treadmill, including walking at three paces (preferred, slower and faster) either without a cognitive task (single-task walking) or while subtracting 1’s or 3’s from a random three-digit number (simple and complex dual-task walking, respectively). Deviation phase (DP) and mean absolute relative phase (MARP) – indicators of variability and phase dynamics of ISC, respectively – were calculated using the data collected by a motion capture system.
Results : The results of three-way analysis of variances showed that slower single- and dual-task walking, significantly increased thigh-shank and shank-foot DP compared to preferred walking speed. During dual-task conditions, these differences were significant between slower and faster walking as well. Furthermore, slower walking significantly increased the thigh-shank MARP under complex dualtask condition and pelvis-thigh MARP while walking with no added cognitive load. However, no significant difference was observed between the three groups.
Conclusion : In conclusion, slow dual-task walking could increase the variability of ISC and make its dynamic behavior more out-of-phase indicating increased control effort for this task. In older people, this may make the control of dual-task walking more difficult and expose them to a higher risk of falling. |