Hormonal responses to three training protocols in rowing.

The aim of this study was to examine the acute responses of serum growth hormone, testosterone, and cortisol to three training protocols in rowing. Six young rowers, members of the national team, carried out three frequently used protocols in rowing, i.e., an endurance, a moderate interval, and a resistance protocol, on separate days in a counterbalanced design. Blood samples were collected before, immediately after, and 4 h after exercise for the determination of growth hormone, testosterone, cortisol, and creatine kinase. All three protocols caused marked increases in growth hormone, the most spectacular being that immediately after the endurance protocol. The change in testosterone concentration immediately after the endurance protocol was significantly higher than the changes after the other two protocols. Cortisol concentration was significantly higher immediately after the endurance protocol than after the other two protocols, but remained relatively low in all cases, suggesting that these protocols did not considerably promote catabolism in muscle tissue. Based on these data, endurance training caused greater responses of the three hormones studied compared to interval or resistance training. In fact, resistance training (at intensities above 85% of 1RM) did not cause any significant changes in the three hormones. We therefore propose that evaluation of training programmes designed for elite athletes should include measurements of hormonal changes in order to ascertain that the programmes do cause the expected adaptations.