A performance comparison of the 20 and 30 meter six-minute walk tests among middle aged and older adults.

Objective: To compare the performance of the Six-Minute Walk Test on 20-meter (6MWT₂₀) and 30-meter (6MWT₃₀) tracks and to test the validity and reliability of the 6MWT₂₀ in middle-aged and older adults. Method: The subjects underwent lung function assessment and performed the 6MWT₃₀ and 6MWT₂₀. Student´s t-tests or Wilcoxon tests were used to compare the variables. The Pearson or Spearman correlation coefficients were used to evaluate the validity of the 6MWT₂₀ and the reliability of the 6MWT₂₀. The 6MWT₃₀ was tested by the two-way mixed model of the Intraclass Correlation Coefficient (ICC 3,1). Results: Twenty-five subjects (age: 60 ± 10 years) walked, on average, 11.0 ± 21.9 m more in the 6MWT₃₀ than in the 6MWT₂₀ (p <.05). The walking distance, the number of steps, the energy expenditure and the movement intensity between the 6MWT₂₀ and 6MWT₃₀ was correlated (r = 0.95; r = 0.81; r = 0.91; r = 0.67; respectively, p <.001). The walking distances showed high reliability and were similar between test and re-test in the 6MWT₃₀ (544 ± 72.1 vs. 551 ± 70.5; p <.05; ICC = 0.97) and in the 6MWT₂₀ (533 ± 73.1 vs. 532 ± 59.1; p <.05; ICC = 0.87). Conclusion: The 6MWT₂₀ performance is lower than the 6MWT₃₀ However, this difference is not clinically relevant. Additionally, the 6MWT₂₀ is a valid and reproducible test to assess the functional capacity of middle-aged and older adults. [ABSTRACT FROM AUTHOR]