Zusammenfassung

Precise estimation of oxygen uptake kinetics parameters is essential to understand its control and/or limit uptake mechanisms. The purpose of the present study was to characterize the oxygen uptake kinetics responses during supramaximal cycle ergometer exercise using two modeling techniques. Eleven male subjects (age = 25.4 ± 4.9 years, height = 177.0 ± 4.0 cm, mass = 77.1 ± 11.3 kg, VO2max = 40.3 ± 6.3 mL.kg-1.min-1) performed a series of square-wave exercise transitions to exhaustion at intensities equivalent to 100, 113, 133 and 153% of VO2max. The time constant of the primary component was estimated with an exponential and semi-logarithmic model, comparisons were made using repeated measures ANOVA and the Tukey post hoc tests, with statistical signifi cance accepted when p<0.05. In order to calculate the time constant by the semi-logarithmic model it is necessary to estimate oxygen demand, which was performed by means of a regression procedure. The exponential model resulted in lower values for the time constant (35.1 ± 8.0s; 32.5 ± 7.4s; 29.6 ± 11.3s; 25.3 ± 7.5s) compared to the semi-logarithmic model (107.9 ± 27.1s; 104.5 ± 24.3s; 114.1 ± 30.4s; 125.3 ± 24.9s) at all intensities. The observation of this confl icting oxygen uptake kinetics behavior depending upon which mathematical model is applied suggests that physiological inferences on the basis of parameters obtained during supra-maximal exercise should be made with caution. Resumo A correta estimativa dos parâmetros da cinética do consumo de oxigênio é fundamental para a interpretação de seus mecanismos de controle e/ou limitação. O objetivo deste estudo foi caracterizar a cinética do consumo de oxigênio em intensidades supra-máximas realizadas em cicloergômetro a partir da utilização de dois modelos matemáticos distintos. Onze indivíduos saudáveis do sexo masculino (idade = 25,4 ± 4,9 anos, estatura = 177,0 ± 4,0 cm, massa corporal = 77,1 ± 11,3 kg, VO2max = 40,3 ± 6,3 mL.kg-1.min-1) realizaram quatro testes retangulares exaustivos de ...