High-intensity interval training (HIIT) is an effective tool to improve cardiovascular fitness and maximal anaerobic power. Different methods of HIIT have been studied but the effect of a maximal effort cycling and very short exercise time (i.e., 4-s) with short recovery time (15-30 s) and a high number of repetitions (i.e., 30 bouts) is unknown.

The investigators examined the effects of training at maximal anaerobic power during cycling (PC) on maximal anaerobic power, peak oxygen consumption (VO2peak), and total blood volume in 11 young healthy individuals (age: 21.3±0.5 y) (6 men, 5 women). Methods: Participants trained three times a week for eight weeks performing a PC program consisting of 30 bouts of 4-s at an all-out intensity (i.e., 2 minutes of exercise per session). The cardiovascular stress progressively increased over the weeks by decreasing the recovery time between sprints (30 to 24 to 15-s) and thus session time decreased from 17 to < 10 min.

Inclusion Criteria:

Young (18-30), Healthy, Recreationally active, but untrained (not meeting ACSM's recommendations of 150 min/week of moderate-vigorous aerobic exercise) -

Exclusion Criteria:

Cardiovascular disease Smoking Subjects who were exercising regularly (>75 min/week) were excluded.

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