O efeito da intensidade do exercício prévio sobre a cinética do consumo de oxigênio durante a corrida

Abstract

Abstract : The oxygen uptake (VO2) measured at pulmonary level reflects changes in oxidative metabolism in active tissues. The aim of this study was to compare the effects of two different modes of prior exercise (sustained severe exercise versus intermittent repeated sprints - IRS) on VO2 kinetics parameters during severe intensity running. Thirteen male amateur futsal players (age 22.8 ± 6.1 years; mass 76.0 ± 10.2 kg; height 178.7 ± 6.6 cm; VO2max 58.1 ± 4.5 ml.kg .min-1) performed a maximal incremental running test on the motorized treadmill for the determination of gas exchange threshold (GET) and maximal VO2 (VO2max). In two different days, the subjects completed a 6-min bout of severe exercise (50 % of the difference between the VO2 at LV and VO2max - ? 50) on a treadmill 6 min after: (1) an identical bout of severe exercise (control) and; (2) a protocol of IRS (6 x 40 m; 1 min of passive recovery). Pearson product moment correlations were used to assess the relationships between parameters. Main effects for all variables were determined using one-way repeated-measures analysis of variance. The level of significance was set at p = 0.05. The time constant of VO2 primary component (tp) was not significantly different in all conditions (control = 16.0 ± 6.3 s; prior severe exercise = 14.3 ± 5.4 s; prior IRS = 12.3± 6.2 s). Prior sprint exercise significantly elevated the blood lactate concentration ([La]; ~11 mmol.L-1), VO2 baseline (0.93 L.min-1) and heart rate (HR; 124 bpm) before to the onset of severe exercise. However, both prior severe running and prior IRS exercise significantly increased the absolute primary VO2 amplitude (3.77 L.min-1 and 3.79 L.min-1, respectively), reduced the amplitude of the VO2 slow component (0.26 L.min-1 and 0.21 L.min-1, respectively) and decreased the mean response time (MRT; 28.9 s and 28.0 s, respectively) in the same magnitude during subsequently bouts (p < 0,05). This study showed that different modes and intensities of prior exercise does not alter the primary phase of VO2 kinetics and trigger similar effect on overall VO2 kinetics as well as in the VO2 slow component amplitude in severe domain intensity running.