Oxygen consumption during machine-assisted and unassisted walking: a pilot study in hemiplegic and healthy humans.

Abstract

To determine whether a gait-training (GT) machine influenced walking time duration and oxygen consumption in hemiplegic patients. Repeated measures with comparison of 2 groups. Physiology laboratories in a rehabilitation hospital. Seven patients with stroke-related hemiplegia (2 men, 5 women; age, 46+/-11y; time since stroke, 12+/-9wk) and 7 healthy subjects (3 men, 4 women; age, 30+/-7y). Floor walking (FW) and GT-assisted walking with and without 50% body-weight support (BWS). Walking time duration, oxygen consumption (Vo(2)), minute ventilation (V(E)), and heart rate. When the condition effect was analyzed independently from the group, mean Vo(2) was higher during FW than during the GT tests (post hoc analysis: FW vs GT, P=.017; FW vs GT+BWS, P<.002). When the groups were compared independently of the condition, the group with hemiplegia had a significantly shorter walking time duration (analysis of variance [ANOVA], P<.001) and a significantly higher Vo(2) as a percentage of baseline (ANOVA, P=.03), compared with the controls. Walking time duration was influenced by walking condition (ANOVA, P<.001; post hoc analysis: FW vs GT, P<.001; FW vs GT+BWS, P<.001). Ve was influenced by walking condition (ANOVA, P=.043; not significant in the post hoc analysis) and was higher in the group with hemiplegia (ANOVA, P=.02). Heart rate was not influenced by walking condition (P=.11). A group effect was found with heart rate in cycles per minute (P=.035) but not as a percentage of baseline. No interaction was found between the ANOVA group-effect factor and the ANOVA walking-condition effect factor. Compared with FW, GT assistance increased walking time duration and reduced Vo(2) in patients with severe hemiplegia.