Muscle metabolism during overground walking in persons with poststroke hemiparesis

Purpose: Muscle energy metabolism is associated with speed, endurance, and effort during walking, yet data regarding muscle metabolism during walking in persons with poststroke hemiparesis have not been published. The primary purpose of this study was to compare the energy metabolism during overground walking in persons with poststroke hemiparesis to controls. The secondary purpose was to determine whether the walking behavior of persons with poststroke hemiparesis conforms to the fuel selection patterns previously observed in controls. Method: O₂ consumption and CO₂ production were measured as 7 individuals with poststroke hemiparesis and 7 age-matched controls walked at self-selected preferred and fast speeds. Indirect calorimetry was used to measure fuel oxidation. Results: Walking speeds and economy were lower in the clinical cohort, although VO₂ and fuel oxidation were consistent between groups. Fat was the dominant fuel source at preferred speeds; whereas, carbohydrate rates increased substantially at fast speeds. Conclusions: Within each condition, similar contributions of fat and carbohydrate were observed despite a wide disparity in speeds. It is hypothesized that fuel selection contributed to preferred walking speeds in the individuals with poststroke hemiparesis and that high rates of carbohydrate oxidation may have prevented higher, more functional, preferred walking speeds.