Oxygen Consumption During Machine-Assisted and Unassisted Walking: A Pilot Study in Hemiplegic and Healthy Humans

David D, Regnaux J-P, Lejaille M, Louis A, Bussel B, Lofaso F. Oxygen consumption during machine-assisted and unassisted walking: a pilot study in hemiplegic and healthy humans.ObjectiveTo determine whether a gait-training (GT) machine influenced walking time duration and oxygen consumption in hemiplegic patients.DesignRepeated measures with comparison of 2 groups.SettingPhysiology laboratories in a rehabilitation hospital.ParticipantsSeven 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).InterventionsFloor walking (FW) and GT-assisted walking with and without 50% body-weight support (BWS).Main Outcome MeasuresWalking time duration, oxygen consumption (V̇o2), minute ventilation (V̇e), and heart rate.ResultsWhen the condition effect was analyzed independently from the group, mean V̇o2 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 V̇o2 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). V̇e 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.ConclusionsCompared with FW, GT assistance increased walking time duration and reduced V̇o2 in patients with severe hemiplegia.