The influence of evaluation protocol on time spent exercising at a high level of oxygen uptake during continuous cycling

AIM: This study evaluated the effects of protocol variation on the time spent exercising at ≥ 95% VO2max during cycle ergometer trials performed at the exercise intensity associated with VO2max (iVO2max).METHODS: Nine male triathletes (age: 32 ± 10 years; body mass: 73.3 ± 6.1 kg; stature: 1.79 ± 0.07 m; VO2max: 3.58 ± 0.45 L.min--1) performed four exercise tests. During tests 1 and 2, participants performed a maximal incremental cycle ergometer test using different stage durations (1 min and 3 min) for the determination of iVO2max(1 min) and iVO2max(3 min). During tests 3 and 4, participants performed a continuous bout of exhaustive cycling at iVO2max(1 min) (CONT1) and iVO2max(3 min) (CONT3).RESULTS: iVO2max(1 min) was significantly greater (P <0.001) than iVO2max(3 min) (340 ± 31 W vs. 299 ± 44 W). Time to exhaustion (TTE) measured during CONT3 was significantly longer (P <0.001) than CONT1 (529 ± 140 s vs. 214 ± 65 s). Time spent at VO2max was significantly longer (P = 0.036) during CONT3 than CONT1 (146 ± 158 s vs. 11 ± 20 s), and time spent at ≥ 95% VO2max was significantly longer (P = 0.005) during CONT3 than CONT1 (326 ± 211 s vs. 57 ± 51 s).CONCLUSION: These results show that when exercising continuously at iVO2max, time spent at ≥ 95% VO2max is influenced by the initial measurement of iVO2max.