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ABSTRACT Objective: To establish normative values and a reference equation for the number of steps climbed during the six-minute step test (6MST) in healthy adults, and to assess the reliability of the test and of the equation. Methods: This was a multicenter cross-sectional study involving 468 healthy volunteers (age range: 18-79 years) recruited from the general community in six research laboratories across different regions of Brazil, which is a country with continental dimensions. The 6MST was performed twice (30-min interval), and clinical, demographic, and functional variables were evaluated. An independent sample of 24 volunteers was evaluated to test the reference equation a posteriori. Results: The number of steps had excellent test-retest reliability (intraclass correlation coefficient = 0.96 [95%CI: 0.95-0.97]), and the mean number of steps was 175 ± 45, the number being 14% greater in males than in females. The best performance on the test was correlated with age (r = −0.60), sex (r = 0.28), weight (r = 0.13), height (r = 0.41), BMI (r = −0.22), waist circumference (r = −0.22), thigh circumference (r = 0.15), FVC (r = 0.54), and physical activity level (r = 0.17; p < 0.05 for all). In the regression analysis, age, sex, height, and weight explained 42% of the variability of the 6MST. Normative values were established for the 6MST according to age and sex. There was no difference between the 6MST values from the independent sample and its predicted values (157 ± 29 steps vs. 161 ± 25 steps; p = 0.47; 97% of predicted values). Conclusions: The normative values and the reference equation for the 6MST in this study seem adequate to accurately predict the physical functional performance in adults in Brazil.
RESUMO Objetivo: Estabelecer valores normativos e uma equação de referência para o número de degraus subidos no teste do degrau de seis minutos (TD6) em adultos saudáveis, bem como avaliar a confiabilidade do teste e da equação. Métodos: Estudo transversal multicêntrico com 468 voluntários saudáveis (faixa etária: 18-79 anos) recrutados na comunidade geral em seis laboratórios de pesquisa em diferentes regiões do Brasil, um país de dimensões continentais. O TD6 foi realizado duas vezes (com 30 min de intervalo entre uma e outra), e foram avaliadas variáveis clínicas, demográficas e funcionais. Uma amostra independente composta por 24 voluntários foi avaliada para testar a equação de referência a posteriori. Resultados: O número de degraus subidos apresentou excelente confiabilidade teste-reteste [coeficiente de correlação intraclasse = 0,96 (IC95%: 0,95-0,97)], e a média de degraus subidos foi de 175 ± 45, sendo 14% maior no sexo masculino. O melhor desempenho no teste correlacionou-se com as seguintes variáveis: idade (r = −0,60), sexo (r = 0,28), peso (r = 0,13), estatura (r = 0,41), IMC (r = −0,22), circunferência da cintura (r = −0,22), circunferência da coxa (r = 0,15), CVF (r = 0,54) e nível de atividade física (r = 0,17; p < 0,05 para todos). Na análise de regressão, idade, sexo, estatura e peso explicaram 42% da variabilidade do TD6. Foram estabelecidos valores normativos para o TD6 de acordo com a idade e o sexo. Não houve diferença entre os valores do TD6 na amostra independente e os valores previstos (157 ± 29 vs. 161 ± 25 degraus subidos; p = 0,47; 97% dos valores previstos). Conclusões: Os valores normativos e a equação de referência para o TD6 neste estudo parecem adequados para predizer com precisão o desempenho físico funcional em adultos no Brasil.
RESUMO
Abstract Aim: This study aimed to compare the performance, metabolic, hemodynamic, and perceived exertion during the 6-minute step test (6MST) conducted with different step heights in healthy subjects and also to compare the performance between different age groups for each step height. The association between age, body mass index, level of physical activity, and lower limb measurements with performance were also evaluated. Methods: This is a cross-sectional study. Anthropometric measures, physical performance, and cardiovascular stress were evaluated during a self-paced 6MST with different step heights in healthy subjects in the age group of 18-59. All the participants underwent three-step tests (15 cm, 20 cm, and 30 cm) on the same day, in a randomized order. Results: Forty participants (20 men and 20 women) performed the tests. The performance in the test for the highest step was significantly lower compared to the step with the lowest height (152 ± 24 vs. 173 ± 27 and 184 ± 33; p < 0,05). The estimated peak oxygen consumption (VO2peak) increased by ∼2.5 mL.kg−1·min−1 with the increase in step height. Hemodynamic variables, such as percent of maximum heart rate (%HRmáx), and systolic blood pressure increased as the step height increased. There was a fair correlation between performance and the level of physical activity in the test with a step height of 15 cm and 20 cm. Conclusion: A higher step height caused greater cardiovascular stress, without exceeding the submaximal levels of the test, indicating that the 6MST can be used as an accurate instrument for evaluating aerobic capacity in healthy individuals.