V̇O ₂ response in supramaximal cycling time trial exercise of 750 to 4000 m

Purpose: Limited research has been done on the V̇O ₂ 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 V̇O ₂ 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 _V̇O2max) 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. V̇O ₂ 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 _V̇O2max in the incremental test was 383 ± 28 W. Mean V̇O _2max was 4.5 ± 0.2 Lmin ^-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 _V̇O2max) 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 V̇O ₂ can be reached within 2 min of strenuous exercise. The larger initial burst in power output in 750 m was accompanied by a faster V̇O ₂ response and seems to be of importance to trigger the aerobic system maximally.