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

Abstract

Objective: To determine whether a gait-training (GT) machine influenced walking time duration and oxygen consumption in hemiplegic patients.

Design: Repeated measures with comparison of 2 groups.

Setting: Physiology laboratories in a rehabilitation hospital.

Participants: 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).

Interventions: Floor walking (FW) and GT-assisted walking with and without 50% body-weight support (BWS).

Main outcome measures: Walking time duration, oxygen consumption (Vo(2)), minute ventilation (V(E)), and heart rate.

Results: 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.

Conclusions: Compared with FW, GT assistance increased walking time duration and reduced Vo(2) in patients with severe hemiplegia.