Introduction: High-intensity interval training is an effective tool to improve cardiovascular fitness and maximal anaerobic power. Different methods of high-intensity interval training have been studied but the effects of repeated maximal effort cycling with very short exercise time (i.e., 4 s) and short recovery time (15-30 s) might suit individuals with limited time to exercise.
Purpose: We examined the effects of training at near maximal anaerobic power during cycling (PC) on maximal anaerobic power, peak oxygen consumption (V˙O2peak), and total blood volume in 11 young healthy individuals (age: 21.3 ± 0.5 yr) (six men, five women).
Methods: Participants trained three times a week for 8 wk performing a PC program consisting of 30 bouts of 4 s at an all-out intensity (i.e., 2 min of exercise per session). The cardiovascular stress progressively increased over the weeks by decreasing the recovery time between sprints (30-24 s to 15 s), and thus, total session time decreased from 17 to <10 min.
Results: Power cycling elicited a 13.2% increase in V˙O2peak (Pre: 2.86 ± 0.18 L·min-1, Post: 3.24 ± 0.21 L·min-1; P = 0.003) and a 7.6% increase in total blood volume (Pre: 5139 ± 199 mL, Post: 5529 ± 342 mL; P < 0.05). Concurrently, maximal anaerobic power increased by 17.2% (Pre: 860 ± 53 W, Post: 1,009 ± 71 W; P < 0.001).
Conclusions: A PC training program employing 30 bouts of 4 s duration for a total of 2 min of exercise, resulting in a total session time of less than 10 min in the last weeks, is effective for improving total blood volume, V˙O2peak and maximal anaerobic power in young healthy individuals over 8 wk. These observations require reconsideration of the minimal amount of exercise needed to significantly increase both maximal aerobic and anaerobic power.
Trial registration: ClinicalTrials.gov NCT04656509.
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