Stride frequency and length adjustment in post-stroke individuals: influence on the margins of stability.

Abstract

OBJECTIVE: To investigate whether post-stroke participants can walk at different combinations of stride frequency and stride length and how these adaptations affect the backward and medio-lateral margins of stability. SETTING: Computer Assisted Rehabilitation Environment (CAREN). PARTICIPANTS: Ten post-stroke individuals. INTERVENTION: Six trials of 2 min walking on a treadmill at different combinations of stride frequency and stride length. Treadmill speed was set at the corresponding speed, and subjects received visual feedback about the required and actual stride length. OUTCOME MEASURES: Mean stride length and frequency and backward and medio-lateral margins of stability for each trial. RESULTS AND CONCLUSION: Stroke patients were able to adjust step length when required, but had difficulty adjusting step frequency. When a stride frequency higher than self-selected stride frequency was imposed patients additionally needed to increase stride length in order to match the imposed treadmill speed. For trials at a high stride frequency, in particular, the increase in the backward and medio-lateral margins of stability was limited. In conclusion, training post-stroke individuals to increase stride frequency during walking might give them more opportunities to increase the margins of stability and consequently reduce fall risk.