During past years much scientific effort has been undertaken to observe the effects of high intensity training (HIT) on endurance performance. Although many studies used varying intensities during the exercise bouts, much less data exists describing how the recovery periods between the intense bouts should be realized. To answer this question, the role of lactate and hence pH has to be considered, since the accumulating lactate during passive recovery is still often considered as major parameter causing muscle fatigue. Latest scientific research reports by contrast that lactate acts as energy reservoir and signal molecule. Due to these findings, the aim of this study was to compare the effects of two different rest protocols power output and physiological parameters. Methods: 12 male endurance athletes (age: 24,4 ± 3,9 years, height: 183,9 ± 4,6 cm, weight: 76,2 ± 7,2 kg) completed two testing sessions on a cycle ergometer. Each testing session consisted of a 10min warm up at 2 Watt/kg followed by four 30sec maximal sprints. The 10min recovery periods between the sprints were either active (ACT, cycling at 1,5 Watt/kg) or completely passive (PAS), which was assigned randomly. Peak Power (PP) and Mean Power (MP) were detected for each sprint. During the recovery intervals capillary blood was used to detect lactate concentrations (Lac) at 0, 1, 3, 5, 7 and 9min. Furthermore pH was measured at 2, 6 and 9min, whereas oxygen uptake (V02peak) was observed during the whole training session. Results: MP was 749 ± 120, 741 ± 122, 720 ± 120 and 709 ± 108 Watt for ACT and 740 ± 109, 712 ± 91, 660 ± 90 and 653 ± 93 Watt for PAS. The difference between the two recovery protocols reached statistical significance at the 3rd & 4th bout. Lac were similar 0, 1, 3 and 5min after the first bout but the concentrations in ACT decreased significantly from 7min and remained lower for all following points of measurement. pH differed significantly from 9min after the second bout, showing higher values for ACT. Analysis of spirometric data revealed no statistical difference for VO2peak during the bouts. Conclusion: Our study revealed that the active recovery protocol was more sufficient to sustain power output over four consecutive maximal bouts. Furthermore it can be speculated if an active recovery process allows an athlete to perform more intense intervals in a row. Anyhow, dependent on the aim of a training intervention one should consider possible differences in metabolic stimuli due to different recovery protocols and resulting lactate concentrations as well as acid-base balances. Several studies provide evidence for an impact of acidosis and lactate on growth hormones and transcription factors which would favor passive recovery protocols due to greater physiological stimuli. To assess these stimuli and characterize subsequent adaptations, not only the character of exercise but also recovery should be considered when developing new training strategies.
© Copyright 2009 14th annual Congress of the European College of Sport Science, Oslo/Norway, June 24-27, 2009, Book of Abstracts. Veröffentlicht von The Norwegian School of Sport Sciences. Alle Rechte vorbehalten.