Objectives: to evaluate the concurrent validity of the six-minute step test (6MST) in assessing exercise capacity of COPD patients using the six-minute walk test (6MWT) as a gold-standard. The predictive validity of the 6MST was assessed to determine a cut-off point for identification of low exercise capacity. Method: thirty-two COPD patients (50-87 years old) with mild to very severe obstruction performed the 6MST and 6MWT twice. Results:Concurrent validity: a strong positive correlation (Pearson) between the number of ascents on the first (T1), second (T2) and the best of both (T1 or T2) tests during the 6MWT was observed. Although a moderate negative correlation with BODE index and FEV1 was found, it was considered insufficient to test the validity, therefore ROC curves were not applied. The predictive validity (ROC) of the 6MST to identify low physical capacity (compared with the 6MWT) using the performance of T1 or T2, or solely T1 was considered accurate, and the area under the curve was 0.8 (IC95% 0.62-0.98) and 0.85 (IC95% 0.70-0.99), respectively. To classify patients, the cut-off points of 86 and 78 steps were chosen, with both values showing 90% of sensitivity and specificity of 64% and 68% for T1 or T2, or solely T1, respectively. Conclusion: The number of steps on the 6MST was valid to verify exercise capacity in COPD patients and the cut-off point of 78 steps was able to identify patients with poor exercise tolerance. Values under this cut-off point are considered to identify patients with a poorer prognosis.

BACKGROUND: Six-minute step test (6MST) has been used to assess functional capacity in chronic conditions; however, its reproducibility in the COPD population has not been evaluated. Our study objective was to evaluate 6MST reproducibility. METHODS: The test was performed in a single 20-cm height step, and subjects were instructed to step up and down (cadence-free) for 6 min. Subjects underwent three tests. The first and second were controlled by the same assessor with a 30-min interval. The third test was controlled by a different assessor one week later. For intrarater comparison, the first and second performances of the test were used, and for inter-assessor comparison, the better performance of the first two tests was compared with the third test. RE-SULTS: Excellent intra-rater and inter-rater relative reproducibility was observed (intraclass correlation coefficient > 0.8), and there was no statistical difference (repeated measures of analysis of variance) among the performances of the three tests. Intra-rater error values were acceptable (mean error of 5.7 steps and limits of agreement between ؊7 and 18 steps). Inter-rater error values were not acceptable (mean error of 4.4 steps and limits of agreement between ؊20 and 29 steps. CONCLUSIONS: 6MST proved to be reproducible in the COPD population when performed by the same assessor.

RESUMOIntrodução: Os testes caminhada de seis minutos (TC6) e degrau de seis minutos (TD6) são meios de avaliação da capacidade funcional. No entanto, pouco se sabe sobre sua reprodutibilidade em adultos jovens. Objetivo: Avaliar a reprodutibilidade relativa e absoluta tanto intra quanto inter-avaliadores do TC6 e TD6 em indivíduos adultos jovens. Métodos: Foram avaliados 33 indivíduos adultos jovens aparentemente saudáveis por meio da espirometria; e realizados os testes TC6 e TD6. Três (T1, T2 e T3) TC6 e TD6 foram feitos em cada indivíduo, sendo o último de cada teste realizado por um avaliador diferente. Para a análise intra-avaliadores foram comparados os desempenhos do T1 e T2 enquanto que a análise inter-avaliadores foi feita pela comparação dos desempenhos do T3 com: T1; T2; e escolha do melhor dos primeiros dois testes. Foi calculado o coeficiente de correlação intra-classe (CCI) como medida da reprodutibilidade relativa; o erro padrão de medida; a diferença mínima detectável; traçados gráficos de Bland-Altman e teste ANOVA para analisar a reprodutibilidade absoluta. Resultados: Observaram-se, nos dois testes funcionais, intra e inter-avaliadores, valores excelentes de reprodutibilidade relativa (CCI>0,75) e a reprodutibilidade absoluta mostrou alto erro. Conclusão: O TD6 e o TC6 apresentaram reprodutibilidade intra e inter-avaliadores excelente para a população adulto jovem, mas altos valores de erro.Palavras-chave: teste de esforço, exercício, adulto jovem. ABSTRACT Introduction: Six Minute Walk Test (6MWT) and Six Minute Step Test (6MST) are tests to evaluate functional capacity. However, reproducibility of these tests is still not well known in young adults. Objective:To evaluate intra and inter-rater relative and absolute reproducibility of 6MWT and 6MST in young adults. Methods: Thirty-three apparently health young adults were evaluated through spirometry, 6MWT and 6MST. Three (T1, T2 and T3)