[Reproducibility of a shuttle walking test in patients with chronic obstructive pulmonary disease]

To analyze the reproducibility of the shuttle walking test (SWT) in comparison to the six min walking test in patients with chronic obstructive pulmonary disease (COPD). The stress tests were performed by 13 patients diagnosed of COPD with moderate-to-severe air flow obstruction (FEV1 45.85 +/- 18.82% of theoretical values). Each patient performed the SWT six times (twice a week over three consecutive weeks). The 6 min walking test was performed an equal number of times. At baseline and at the end of both types of test, heart rate and degree of dyspnea (on a modified version of Borg's scale) were recorded, as well as the level reached and the number of meters walked. No significant differences in distance walked, heart rate or degree of dyspnea were found for the six SWTs performed. The interclass correlation coefficients for the aforementioned parameters were 0.875, 0.879 and 0.896, respectively; the variation coefficient for distance covered ranged between -10.7% and 10.2%. In the six min walking test significant differences were seen between distance walked in the first two tests and the other four tests. The variation co-efficient ranged between 11.4% and 17.5%. The SWT is a reproducible stress test in which the patient must exert progressively greater effort. The low degree of variability observed assures that the level of effort attained is steady and consistent.