Responses of blood hormones to the maximal rowing ergometer test in college rowers.

BACKGROUND: The purposes of this study were to investigate the resting levels and the acute hormonal response of total testosterone (Ttot), free testosterone (Tfree), cortisol (C) and Tfree:C ratio to the 6-minute all-out rowing ergometer test. METHODS.

EXPERIMENTAL DESIGN: Cross-sectional study to investigate the responses of blood hormones to the maximal rowing ergometer test in college rowers.

PARTICIPANTS: Eight college level male rowers (22.0 +/- 2.8 yrs, 191.8 +/- 4.1 cm, 85.4 +/- 4.3 kg, BMI: 23.2 +/- 1.3 kg x m(-2)) took part in this investigation.

INTERVENTIONS: a graded exercise test at the intensities of 150, 200 and 250 W (6-minute each) and a 6-minute all-out test on a rowing ergometer (Concept II, Morrisville, USA) were performed at separate measurement sessions.

MEASURES: Heart rate (HR) was recorded at the end of each load during a graded exercise test. Individual physical working capacity of rowers was calculated at the maximum HR recorded during a 6-minute all-out test. Venous blood samples were obtained 3 minutes before and immediately after the 6-minute all-out test to determine the concentration of Ttot, Tfree, Tfree:C ratio, glucose and lactate (LA) in blood.

RESULTS: Mean power was 354.3 +/- 26.8 W and HR 190.9 +/- 5.1 beats x min(-1) during the all-out test. Mean blood LA concentration at the end of the all-out test was 13.4 +/- 1.44 mmol x l(-1). The all-out test on the rowing ergometer did not change significantly the concentration of Ttot (before: 17.54+/-4.34; after: 20.03 +/- 4.80 nmol x l(-1)), Tfree (before: 0.423 +/- 0.111; after: 0.436 +/- 0.112), C (before: 477.50 +/- 119.34; after: 477.63+/-132.51 nmol x l(-1)) and Tfree:C ratio (before: 0.922 +/- 0.282; after: 0.973 +/- 0.320 x10(-3)). The transformation of these hormone values to effect sizes (ES) demonstrated that all-out test only moderately (ES < 0.61) influenced these hormone levels. Significant relationships were observed between the resting levels of Ttot and Tfree, and mean power of the 6-minute all-out test (r = 0.65 and r = 0.86, respectively). There was a non-significant increase in the level of Ttot following the all-out rowing ergometer test which was significantly related to mean power (r = 0.73) and covered distance (r = 0.67).

CONCLUSIONS: The results suggest that there are no significant changes in hormone levels during a 6-minute all-out rowing ergometer test. However, rowing performance is positively related to the resting values of Ttot and Tfree, and the non-significant changes in Ttot level following a 6-minute all-out test.