Fig. 1

Protocols of the three experimental studies, denoted by k = 1, 2, 3, respectively. They differ from each other by different warm-up conditions. The thick arrows indicate the blood sampling times; −16, −4 and 0 mean “at rest,” “the end of warming up” and “1 min before the maximal exercise,” respectively. During the 12 min between −16 and −4, k = 1 means “moderate warm-up” of constant intensity at 60% of the individual VO_2peak, k = 2 means “intensive warm-up” including three 10-s periods at 200% of the individual VO_2peak and k = 3 means without warm-up