Young and old adults prioritize dynamic stability control following gait perturbations when performing a concurrent...

There are conflicting results regarding the effect of aging on postural prioritization. The present study investigated balance recovery performance of young and old adults following unexpected gait perturbations in a dual task condition. Thirty-two young and 30 elderly male subjects were assigned to either control or dual task group. After baseline assessment, an unexpected gait perturbation was induced by a sudden change of surface rigidity. The dual task groups performed a mental arithmetic task. Dynamic stability was quantified based on the 'extrapolated center of mass' concept. The margin of stability decreased significantly at touchdown of the recovery leg following the unexpected perturbation (P) compared with baseline (base), yet irrespective of cognitive load (base: -4.63cm; P: -13.32cm; p<0.05). The number of errors in the cognitive task increased significantly (base: 0.13; P: 0.48; p<0.05) in both age groups. Since the stability performance was unaffected by additional cognitive load, whereas the cognitive task performance declined following the perturbation in both groups, it is concluded that postural prioritization occurs independent of age in response to unexpected gait perturbations.