High-intensity decreasing interval training (HIDIT) increases time above 90% (V) over dotO2peak

Purpose Training near (V) over dotO(2)max is considered to be the most effective way to enhance (V) over dotO(2)max. High-intensity interval training (HIIT) is a well-known time-efficient training method for improving cardiorespiratory and metabolic function and (V) over dotO(2)max. While long HIIT bouts allow (V) over dotO(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% (V) over dotO(2)peak (T > 90% (V) over dotO(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 center dot recovery(-1). The protocols consisted of long-interval (HIIT) (LIHIIT, 3 min work-2 min recovery), short-interval (HIIT) -(SIHIIT, 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% (V) over dotO(2)peak, Tlim, blood lactate [La], and rate of perceived exertion (RPE) were measured at Tlim. Results T > 90% (V) over dotO(2)peak was greater in HIDIT (312 +/- 207 s) than in -SIHIIT (182 +/- 225 s; P = 0.036) or -LIHIIT (179 +/- 145 s; P = 0.027). Tlim was not significantly different (P > 0.05) between HIDIT (798 +/- 185 s), -SIHIIT (714 +/- 265 s), and -LIHIIT (664 +/- 282). At Tlim, no differences in [La] and RPE were found between protocols (P > 0.05). Conclusion HIDIT showed the highest T > 90% (V) over dotO(2)peak, suggesting that it may be a good strategy to increase time close to (V) over dotO(2)peak, despite similar Tlim, [La], and RPE at Tlim.