Purpose: Limited research has been done on the .VO2 response to time trial exercise in the supramaximal domain or during free range exercise typical of competition. The present study was designed to measure and to model the .VO2 response during supramaximal time trial exercise.
Methods: Well-trained cyclists (n = 9) performed a 1-min incremental exercise test to obtain maximal power output (P (.VO2max)) and four cycle ergometer time trials of different distances (750, 1500, 2500, and 4000 m). Athletes were instructed to finish in as little time as possible. .VO2 was measured breath-by-breath and modeled monoexponentially over the first 54 s (750 m) or 114 s (1500, 2500, and 4000 m) of the time trials.
Results: Mean P (.VO2max) in the incremental test was 383 +/- 28 W. Mean .VO(2max) was 4.5 +/- 0.2 L.min(-1). All time trials were characterized by an initial burst in power output during the first 15 s (175 +/- 23%, 149 +/- 14%, 145 +/- 14%, 139 +/- 10% P (.VO2max) being largest for 750 m. Simultaneously, the mean response time was significantly smaller in 750 m compared with all other trials (18.8 +/- 2.2, 20.9 +/- 1.9, 20.8 +/- 1.5, and 21.2 +/- 2.2 s).
Conclusion: Near maximal values of .VO2 can be reached within 2 min of strenuous exercise. The larger initial burst in power output in 750 m was accompanied by a faster .VO2 response and seems to be of importance to trigger the aerobic system maximally.