Influence of Speed on Walking Economy Poststroke

Abstract

Background and Objective. Walking speed influences energy cost in healthy adults, but its influence when walking is impaired due to stroke is not clear. This study investigated the effect of manipulating walking speed on the energy economy of walking poststroke. Methods. Sixteen persons with chronic stroke underwent a clinical examination, including several lower extremity impairment measures. consumption ( VO2) was measured as they walked at their self-selected speed (Free), 20% slower (Slow), their fastest possible speed (Fastest), and 2 speeds between Free and Fastest speeds. VO2was normalized to body mass and speed, resulting in energy cost per meter walked (CW). Results. A main effect for speed was observed ( P = .00001), with faster than self-selected speeds showing greater relative economy as a whole. However, for 5 subjects with the fastest walking speeds (>1.2 m/s), there was a trend toward decreasing relative economy at speeds higher than self-selected speed ( P = .18). There was a negative correlation between improvement in CW at the most economical speed and ( a) Free speed ( r = −.857; P < .0001) and ( b) lower extremity Fugl-Meyer scores ( r = −.653; P = .006). Conclusions. For those poststroke whose fastest walking speed after stroke is below 1.2 m/s, walking economy improves when speed is increased above the self-selected walking speed. The results suggest that for persons poststroke with very slow self-selected walking speeds, improvements in walking speed could be accompanied by improvements in walking economy if faster walking speeds can be attained through intervention.