High-intensity decreasing interval training (HIDIT) increases time above 90% [Formula: see text] O(2)peak

PURPOSE: Training near [Formula: see text] O(2)max is considered to be the most effective way to enhance [Formula: see text] O(2)max. High-intensity interval training (HIIT) is a well-known time-efficient training method for improving cardiorespiratory and metabolic function and [Formula: see text] O(2)max. While long HIIT bouts allow [Formula: see text] O(2)max to be achieved quickly, short HIIT bouts improve time to exhaustion (Tlim). The aim of this study was to evaluate the time spent above 90% [Formula: see text] O(2)peak (T > 90% [Formula: see text] O(2)peak) during three different HIIT protocols. METHODS: Twelve cyclists performed three HIIT sessions. Each protocol had the same work and recovery power and ratio of work·recovery(−1). The protocols consisted of long-interval HIIT (LI(HIIT), 3 min work—2 min recovery), short-interval HIIT (SI(HIIT), 30 s work—20 s recovery), and high-intensity decreasing interval training (HIDIT, work from 3 min to 30 s and recovery from 2 min to 20 s). T > 90% [Formula: see text] O(2)peak, Tlim, blood lactate [La], and rate of perceived exertion (RPE) were measured at Tlim. RESULTS: T > 90% [Formula: see text] O(2)peak was greater in HIDIT (312 ± 207 s) than in SI(HIIT) (182 ± 225 s; P = 0.036) or LI(HIIT) (179 ± 145 s; P = 0.027). Tlim was not significantly different (P > 0.05) between HIDIT (798 ± 185 s), SI(HIIT) (714 ± 265 s), and LI(HIIT) (664 ± 282). At Tlim, no differences in [La] and RPE were found between protocols (P > 0.05). CONCLUSION: HIDIT showed the highest T > 90% [Formula: see text] O(2)peak, suggesting that it may be a good strategy to increase time close to [Formula: see text] O(2)peak, despite similar Tlim, [La], and RPE at Tlim.