Abstract

Aim. The aim of the present investigation was to study the stability of fasting plasma leptin levels in blood and the possible relationship of fasting plasma leptin with body composition and performance parameters in female rowers. Methods. Ten college level rowers (19.4±1.6 years; 173.4±5.1 cm; 67.7±10.4 kg; body fat%: 27.8±7.8 %) participated in this study. Venous blood samples for the determination of leptin, insulin and glucose were obtained during the follicular phase of the menstrual cycle in the morning after an overnight fast twice with 48 h between sampling (leptin concentration: 11.0±8.1 vs 11.6±9.4 ng.ml-1; p=0.970). Insulin resistance was calculated through the fasting insulin resistance index (FIRI: [insulinxglucose/25]). Body composition was measured using dual-energy X-ray absorptiometry (Lunar DPX-IQ scanner, Lunar Corporation, Madison, USA), and analyzed for fat (FM) and lean (LM) tissue mass. Total, extracellular and intracellular body water were estimated by means of a multifrequency impedance analyzer (Multiscan-5000, Bodystat Ltd, Isle of Man, UK). Two thousand metre rowing performance was assessed on a rowing ergometer (Concept II, Morrisville, USA) and maximal oxygen consumption (TrueMax 2400 Metabolic Measurement System, Parvo Medics, USA) during the test was measured. Of the determined body composition parameters, body mass and FM were related to plasma leptin (r>0.71; p<0.020). All rowing performance parameters were also correlated with plasma leptin(r<-0.66; p<0.037). Results. Stepwise regression revealed only FM (adj. R2=0.731; p<0.00) from body composition and maximal oxygen consumption per kg body mass (adj. R2=0.65 l ; p<0.003) from rowing performance parameters as the main determinant for the variation in leptin in female rowers. Conclusion. The present study showed that leptin is highly related to the specific body composition and to performance parameters in female rowers. It appears that relative oxygen consumption during 2.000 metre rowing ergometer race, which is also a function of body composition, is the main determinant of leptin variance from performance parameters in female rowers. Verf.-Referat