Walking Capacity in Parkinson’s Disease: Test–Retest Reliability of the 6-min Walk Test on a Non-Linear Circuit

Background/Objectives: The 6 min walk test (6MWT) has been used to measure the level of walking capacity in people with Parkinson’s disease (PD). However, the use of a non-linear circuit has not yet been investigated deeply. Thus, the aim of this study was to evaluate the test–retest reliability of the 6 min walk test in a rectangular circuit in people with PD. Methods: Forty-two people with PD (men = 27, women = 15), mean age 66 ± 9.61 years, participated. All of them were in ON state. Each patient performed the 6MWT on 2 test days separated by 1 week, walking at a constant speed on a 20 m × 3.5 m circuit. Test–retest reliability was assessed using the intraclass correlation coefficient (ICC), minimal detectable change (MDC), and standard error of measurement (SEM), and Student’s t-test was applied to determine whether there were statistically significant differences between the test and the retest. Results: The ICC values for the total sample were excellent (>0.90) in both men and women. In addition, they had similar reliability, although slightly higher in women. The results showed that, for the total sample, a MDC < 17% can be considered as a true change for this procedure. The SEM percentage was 6.1%. Conclusions: The 6MWT, performed on a rectangular circuit, demonstrated excellent test–retest reliability in patients with Parkinson’s disease.