Temporal-spatial gait parameter models of very slow walking.

This study assessed the relationship between walking speed and common temporal-spatial stride-parameters to determine if a change in gait strategy occurs at extremely slow walking speeds. Stride-parameter models that represent slow walking can act as a reference for lower extremity exoskeleton and powered orthosis controls since these devices typically operate at walking speeds less than 0.4 m/s. Full-body motion capture data were collected from 30 health adults while walking on a self-paced treadmill, within a CAREN-Extended virtual reality environment. Kinematic data were collected for 0.2-0.8 m/s, and self-selected walking speed. Eight temporal stride-parameters were determined and their relationship to walking speed was assessed using linear and quadratic regression. Stride-length, step-length, and step-frequency were linearly related to walking speed, even at speeds below 0.4 m/s. An inflection point at 0.5 m/s was found for stride-time, step-time, stance-time, and double support time. Equations were defined for each stride-parameter, with equation outputs producing correlations greater than 0.91 with the test data. This inflection point suggests a change in gait strategy at very slow walking speeds favouring greater ground contact time.