title: Associations Between Foot Placement Asymmetries and Metabolic Cost of Transport in Hemiparetic Gait.
abstract: Stroke survivors often have a slow, asymmetric walking pattern. They also walk with a higher metabolic cost than healthy, age-matched controls. It is often assumed that spatial-temporal asymmetries contribute to the increased metabolic cost of walking poststroke. However, elucidating this relationship is made challenging because of the interdependence between spatial-temporal asymmetries, walking speed, and metabolic cost. Here, we address these potential confounds by measuring speed-dependent changes in metabolic cost and implementing a recently developed approach to dissociate spatial versus temporal contributions to asymmetry in a sample of stroke survivors. We used expired gas analysis to compute the metabolic cost of transport (CoT) for each participant at 4 different walking speeds: self-selected speed, 80% and 120% of their self-selected speed, and their fastest comfortable speed. We also computed CoT for a sample of age- and gender-matched control participants who walked at the same speeds as their matched stroke survivor. Kinematic data were used to compute the magnitude of a number of variables characterizing spatial-temporal asymmetries. Across all speeds, stroke survivors had a higher CoT than controls. We also found that our sample of stroke survivors did not choose a self-selected speed that minimized CoT, contrary to typical observations in healthy controls. Multiple regression analyses revealed negative associations between speed and CoT and a positive association between asymmetries in foot placement relative to the trunk and CoT. These findings suggest that interventions designed to increase self-selected walking speed and reduce foot-placement asymmetries may be ideal for improving walking economy poststroke.
authors: 1 University of Southern California, Los Angeles, CA, USA.
authors: James M
authors: JM
authors: Finley
authors: 2 Kennedy Krieger Institute, Baltimore, MD, USA.|3 Johns Hopkins University, Baltimore, MD, USA.
authors: Amy J
authors: AJ
authors: Bastian
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D005528:Foot / Q000503:physiopathology*; D007839:Functional Laterality; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010291:Paresis / Q000503:physiopathology*; D012044:Regression Analysis; D020521:Stroke / Q000503:physiopathology*
keywords: asymmetry; locomotion; metabolic cost; stroke