Abstract
The purpose of this study was to test the hypothesis that subjects having a shorter time constant for the fast component of VO2 kinetics in a transition from rest to constant exercise would maintain their speed for a longer time during repeated sprint exercise (RSE). Eleven male soccer players completed a graded test, two constant exercises at 60% maximal aerobic speed and RSE, consisting of fifteen 40-m sprints alternated with 25 s of active recovery. All the tests were performed on the field (200 m indoor track). The parameters of the VO2 kinetics (time delay, time constant, and amplitude of the primary phase) during the two constant exercises were modeled. All subjects elicited VO2 during the RSE. A significant correlation was found between VO2 and the relative decrease in speed during the 15 sprints (r=0.71; p 0.05). There were significant correlations between the time constant of the primary phase and the relative decrease in speed during the 15 sprints (r=0.80; p < 0.01) and the cumulated time for the 15 sprints (r=0.80; p < 0.01). These results suggest that individuals with faster VO2 kinetics during constant load exercise might also have a faster adjustment of VO2 during RSE leading to a shorter cumulated time and a lower relative decrease in speed during the 15 sprints.