Walking on an Oscillating Treadmill: Strategies of Stride-Time Adaptation

Abstract

Gains in mobility, balance, and gait quality have been observed in clinical populations after treadmill training. In our laboratory, we introduce healthy adults to treadmill training programs in an effort to boost their adaptive generalization skills. We hypothesized that some individuals are more naturally predisposed to gait adaptation than others. Stride-time data from 20 healthy adults were collected while they walked on a laterally oscillating treadmill for the first time. We predicted that the more plastic adapters would rapidly synchronize their stride frequencies to the treadmill's oscillation frequency. A treadmill mounted on a 6-degrees-of-freedom motion base platform was programmed to move laterally in a continuous, sinusoidal pattern for 20 min while participants walked at 1.1 m/s. Twenty-five percent of our participants showed a prolonged uninstructed entrained response. Those who did not entrain were still able to adapt to the novel locomotor challenge by applying various alternative strategies. Although entrainment was not required for adaptation, we report compelling evidence that the frequency of the support-surface motion influenced the adapted strategies of 80% of our participants.