Influence of repeated sprint training on pulmonary O2 uptake and muscle deoxygenation kinetics in humans

Abstract

We hypothesized that a short-term training program involving repeated all-out sprint training (RST) would be more effective than work-matched, low-intensity endurance training (ET) in enhancing the kinetics of oxygen uptake (V̇o2) and muscle deoxygenation {deoxyhemoglobin concentration ([HHb])} following the onset of exercise. Twenty-four recreationally active subjects (15 men, mean ± SD: age 21 ± 4 yr, height 173 ± 9 cm, body mass 71 ± 11 kg) were allocated to one of three groups: RST, which completed six sessions of four to seven 30-s RSTs; ET, which completed six sessions of work-matched, moderate-intensity cycling; and a control group (CON). All subjects completed moderate-intensity and severe-intensity “step” exercise transitions before (Pre) and after the 2-wk intervention period (Post). Following RST, [HHb] kinetics were speeded, and the amplitude of the [HHb] response was increased during both moderate and severe exercise ( P < 0.05); the phase II V̇o2 kinetics were accelerated for both moderate (Pre: 28 ± 8, Post: 21 ± 8 s; P < 0.01) and severe (Pre: 29 ± 5, Post: 23 ± 5 s; P < 0.05) exercise; the amplitude of the V̇o2 slow component was reduced (Pre: 0.52 ± 0.19, Post: 0.40 ± 0.17 l/min; P < 0.01); and exercise tolerance during severe exercise was improved by 53% (Pre: 700 ± 234, Post: 1,074 ± 431 s; P < 0.01). None of these parameters was significantly altered in the ET and CON groups. Six sessions of RST, but not ET, resulted in changes in [HHb] kinetics consistent with enhanced fractional muscle O2 extraction, faster V̇o2 kinetics, and an increased tolerance to high-intensity exercise.