Relationship between ambulatory capacity and cardiorespiratory fitness in chronic stroke - Influence of stroke-specific impairments

Study objectives: To identify the following in individuals with chronic stroke: (1) the relationship between the maximal oxygen consumption (Vo(2)max) during cycle ergometry and the distance covered in the 6-min walk test (6MWT), and (2) the stroke-specific impairments that are important determinants for the 6MWT distance. Design: Cross-sectional study using a convenience sample. Setting: Exercise testing laboratory in a tertiary rehabilitation center. Participants: Sixty-three older adults (mean age :+/- SD, 65.3 +/- 8.7 years) with an average poststroke interval of 5.5 +/- 4.9 years. Intervention: Not applicable. Main outcome measures: Each subject underwent a maximal cycle ergometer test and a 6MWT. Oxygen consumption (Vo(2)) was measured during both tests. Subjects were also evaluated for Berg balance scale, modified Ashworth scale of spasticity, isometric knee extension strength, and percentage of body fat. Results: The 6MWT distance had a low correlation with the Vo(2)max (r = 0.402). Balance, knee extension strength, and spasticity were all significant determinants for the 6MWT distance, with balance being the major contributor for the 6MWT distance, accounting for 66.5% of its variance. Conclusions: Factors other than the cardiorespiratory status considerably influenced the ambulatory capacity as measured by the 6MWT. The 6MWT distance alone should not be used to indicate cardiorespiratory fitness in individuals with chronic stroke.