Int J Sports Med 2014; 35(04): 316-322
DOI: 10.1055/s-0033-1353141
Training & Testing
© Georg Thieme Verlag KG Stuttgart · New York

Acute Hormonal Responses Before and After 2 Weeks of HIT in Well Trained Junior Triathletes

C. Zinner
1  Institute of Training Science and Sport Informatics, German Sport University Cologne, Germany
,
P. Wahl
1  Institute of Training Science and Sport Informatics, German Sport University Cologne, Germany
,
S. Achtzehn
1  Institute of Training Science and Sport Informatics, German Sport University Cologne, Germany
,
J. L. Reed
2  Minto Prevention and Rehabilitation Centre, University of Ottawa Heart Institute, Ottawa, Canada
,
J. Mester
1  Institute of Training Science and Sport Informatics, German Sport University Cologne, Germany
› Author Affiliations
Further Information

Publication History



accepted after revision 27 June 2013

Publication Date:
30 September 2013 (online)

Abstract

The aim was to compare the acute hormonal response to a single HIT session at the beginning and end of a HIT shock microcycle. 13 male junior triathletes (15.8±1.8 yrs.) performed 16 HIT sessions within a 2 week period. Venous blood samples were collected before and after the first and last HIT session. Significant increases in cortisol (first session +89.7%; last session +70.3%) and hGH (first session +435.1%; last session +314.6%) concentrations were observed after both training sessions (P<0.05). The acute responses of cortisol, hGH, T3, and fT3 were not different between the first and last HIT sessions (P=1.00). Although no acute changes in testosterone were detected after the training sessions, testosterone concentrations were significantly higher at all time points (62.6–80.1%) during the last compared to first training session (P≤0.001). Findings from the present study reveal that 16 sessions of HIT led to significant increases in baseline concentrations of serum testosterone. This might indicate a heightened anabolic state even in junior triathletes. Based on the hormonal data, we conclude that at the end of this 2 week microcycle no familiarization effect was evident and that the training stimulus produced by HIT was still great enough to “stress” the athletes and induce positive training adaptations.