Variability in inter-joint coordination during walking of elderly adults and its association with clinical balance measures

BackgroundWalking requires coordination among multiple joints. Little is known about the association between the coordination ability and fall risks in elderly adults. This study investigated variability of inter-joint coordination in elderly adults and determined its correlation to clinical balance measures.MethodsGait analyses of 15 non-fallers and 15 fallers were performed during walking. Continuous relative phase, derived from phase angles of two adjacent joints, was used to assess the inter-joint coordination. Variability of inter-joint coordination was calculated as the average standard deviation of all points on the ensemble continuous relative phase curve over a gait cycle, namely the deviation phase. Outcomes from three clinical balance tests, including Berg Balance Test, Dynamic Gait Index and Timed Up-and-Go, were examined.FindingsNo significant group differences were detected in hip-knee deviation phase values after accounting for differences in walking speeds. For the knee-ankle deviation phase, fallers demonstrated significantly greater values in the stance phase but smaller values in the swing phase. The hip-knee deviation phase values demonstrated a negative correlation with Dynamic Gait Index, and the knee-ankle deviation phase values had a negative correlation with Dynamic Gait Index and a positive correlation with Timed Up-and-Go time.InterpretationExcessive variability of the supporting limb and reduced variability of the swing limb in knee-ankle inter-joint coordination of fallers may contribute to their risk of imbalance or tripping during walking. Compared to Berg Balance Test and Timed Up-and-Go, Dynamic Gait Index scores might be more sensitive to reflect declines in inter-joint coordination during walking.