Aim: The aim of this study was to investigate the hormonal response at rest and during maximal 2,000 m rowing ergometer test in 12 highly trained male rowers before and after 3 week heavy training, and after 2 week tapering periods.
Methods: Venous blood samples were obtained before, immediately after and after 30 min of recovery of the rowing performance test. Testosterone, cortisol and sex hormone binding globulin were measured, and free testosterone and the free testosterone: cortisol ratio calculated.
Results: Mean training time was about 100% higher during the heavy training period (17.5 h x week(-1)) compared to the tapering period (8.9 h x week(-1)). Two thousand meter rowing ergometer performance parameters were not different between 3 tests. Resting testosterone and cortisol values were not different between 3 tests. Three week heavy training period induced significant reductions in resting free testosterone and free testosterone: cortisol ratio. Resting free testosterone and free testosterone: cortisol ratio were increased to the pretraining level after 2 week tapering period. A significantly (p<0.05) lower maximal exercise-induced increase of the free testosterone level was measured after heavy training period. The response of cortisol was unchanged and free testosterone: cortisol ratio demonstrated a trend (p>0.05) for a decrease after heavy training period.
Conclusions: Our findings indicate that the first sign of decreased adaptivity in athletes is a decreased resting level of free testosterone and a lower maximal exercise-induced increase in free testosterone concentration. In addition, heavy training load higher than 1,000 min per week can be sustained for 3 weeks when sufficient tapering period is followed in highly trained male rowers.