Evaluation of Fall Recovery and Gait Adaptation to Medial and Lateral Gait Perturbations

The aim of this study was to develop an active gait perturbation system and to evaluate its efficacy in evaluating fall recovery and gait adaptation. We hypothesized that a translating perturbation during the single stance phase would alter gait adaptations, in terms of gait parameters and muscle co-contractions, during recovery to maintain dynamic stability for continued walking. A customized miniature treadmill, built on a large force plate and embedded perpendicular to the walkway, was used to translate the loaded stance foot medially and laterally to interrupt swing foot trajectory. The perturbation was activated when the stepping foot was placed entirely on the belt to ensure the foot would remain on the belt when translated. The translating floor surface was applied to 10 young, healthy adult subjects (5 males, 5 females; aged <35y) during normal walking at their preferred speed. Step length, step width, step duration, and muscle co-contraction at the ankle of the stance limb was examined before, during, and after both the medial and lateral translations. Shorter step length, wider step width, faster step duration, and higher muscle co-contraction at the ankle joint were observed strategies for fall recovery and regaining body stability.