Abstract des Autors

We examined the effects of sodium bicarbonate (BIC) and sodium citrate (CIT) ingestion on distance running performance. Seven male runners (mean VO2max = 61.7(SEM 1.7) ml/kg/min) performed three 30-min treadmill runs at the lactate threshold (LT) each followed by a run to exhaustion at 110% of LT. The runs were double-blind and randomly assigned from BIC (0.3 g/kg body mass), CIT (0.5 g/kg body mass) and placebo (PLC, wheat flour, 0.5 g/kg body mass). Venous blood samples were collected at 5, 15 and 25 min during the run and immediately post-exhaustion (POST-EX) and analysed for pH, and the concentrations of lactate ([la-]b) and bicarbonate ([HCO3-]). Performance was measured as running time to exhaustion at 110% of LT (TIME-EX). The pH was significantly higher for the BIC and CIT trials during exercise, but not POST-EX compared to PLC. The [la-]b was significantly higher for the CIT trial compared to PLC during exercise, and for both CIT and BIC compared to PLC at POST-EX. Blood [HCO3-] was significantly higher during exercise for BIC compared to PLC. TIME-EX was not significantly different among treatments: BIC 287(SEM 47.4) s; CIT 172.8(SEM 29.7) s; and PLC 222.3(SEM 39.7) s. Despite the fact that buffer ingestion produced favourable metabolic conditions during 30 min of high intensity steady-state exercise, a significant improvement in the subsequent maximal exercise run to exhaustion did not occur. Verf.-Referat