Dynamic stability control during perturbed walking can be assessed by a reduced kinematic model across the adult female lifespan

The current study aimed to determine potential differences in dynamic stability control during perturbed walking across the adult female lifespan and to test the hypothesis that such differences can be assessed by a reduced kinematic model. 11 young-aged (22-30 years), 9 middle-aged (41-59 years) and 14 old-aged (62-75 years) female adults walked on a treadmill while the right leg was unexpectedly perturbed once during the swing phase. Margin of stability (MS) at touchdown was investigated using a full body and a reduced kinematic model. After the perturbation, all age groups showed a lower MS compared to non-perturbed gait (baseline), leading to negative MS. Four old-aged adults failed to cope with the task (only preventing a fall by grasping). The remaining ten old-aged and the middle-aged subjects required three more recovery steps than the young-aged adults to get back to baseline MS. Moreover, there were no differences between kinematic models, and both methods demonstrated similar age-related findings. We concluded that the ability to control dynamic stability during perturbed walking by enlarging the base of support has already begun to deteriorate by middle age. Further, the valid agreement between kinematic models shows that such differences can be assessed by using just four body markers.