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.