The Distance Covered in Field Tests is more Explained by Walking Capacity than by Cardiorespiratory Fitness after Stroke

Abstract

Objectives: To investigate if the distance covered in the Six-Minute Walk Test (6MWT) and in the Incremental Shuttle Walk Test (ISWT) is most strongly explained by walking capacity or cardiorespiratory fitness (CRF) measures in individuals after chronic stroke.

Materials and methods: This is a cross-sectional study. Individuals after chronic stroke aged at least 20 years old and able to walk at least 10 minutes independently were included. The distance covered (meters) in the 6 MWT and ISWT (dependent variables), comfortable and fast gait speed obtained by the 10 m walk test (10 mWT) (walking capacity measures; independent variables) and peak oxygen consumption (VO_2peak; CRF measure; independent variable) (ml.kg^-1.min^-1) obtained by the cardiopulmonary exercise test (CPET) were obtained. Linear regression analyses were performed (α = 5%).

Results: Fifty individuals (mean age of 55±12 years and mean time after stroke of 67±74 months) were included. Comfortable and fast gait speeds were the variables that most strongly explained the distance covered in the field tests: 6MWT (R² = 0.614, β = 0.784, p < 0.001 and R² = 0.615, β = 0.778, p < 0.001, respectively) and ISWT (R² = 0.450, β = 0.671, p < 0.001 and R² = 0.456, β = 0.746, p < 0.001, respectively). On the other hand, for the VO_2peak, the following models were generated: 6MWT (R² = 0.280, β = 0.530, p < 0.001) and ISWT (R² = 0.154, β = 0.393, p = 0.005)_. CONCLUSIONS: The distance covered in the field tests (6MWT and ISWT) is more suitable to support inferences about the walking capacity than about the CRF of individuals after chronic stroke.

Keywords: Cardiorespiratory fitness; Oxygen consumption; Stroke; Walk test; Walking.