The purpose of this study was to determine whether sodium phosphate ingestion had a repeatable effect on exercise performance if supplementation was repeated. Methods: Nine well-trained male cyclists (VO2peak 65.2 ± 4.8 ml/kg/min; mean ± SD) participated in a randomised, repeated-measures, double-blind crossover study. First, each participant completed a baseline 1000 kJ cycling time trial, followed 48 hours later by an incremental exercise test to exhaustion to determine maximal oxygen consumption. Upon completion of these baseline trials, participants completed three 6 day loading phases of supplementation with either 50 mg/kg/FFM/day of tribasic sodium phosphate or a combined glucose and NaCl placebo (two phases involved supplementation with sodium phosphate and one phase with placebo in a randomised order). On the 7th day, participants again performed the 1000 kJ cycling time trial followed 48 hours later by the incremental exercise test to exhaustion. Time to completion, cycling power output, heart rate and lactate were assessed during the time trial, while oxygen consumption and lactate were determined for each stage of the incremental test. Participants had a 14 day washout period between finishing one loading phase and starting the next. Results: There was no significant difference in time to completion of the 1000 kJ cycling time trial between sodium phosphate and placebo supplementation phases (p =0.573), however, there was a tendency for faster completion time (mean 1.9-2.7 % or 58-69 s) and mean power output (2.1-3.3 % or 4.9-6.8 W) with sodium phosphate supplementation when compared to baseline or placebo conditions. There was a significant increase (p < 0.01) in maximal oxygen consumption after the first phase of phosphate loading compared with baseline and placebo conditions (p < 0.01, 3.5- 4.3 %), with further increases displayed in the second phase of phosphate loading compared with the first phosphate supplementation phase (p < 0.05, 7.5- 7.9 %). No differences in heart rate or lactate values were found between conditions. Discussion: In summary, sodium phosphate supplementation resulted in increased maximal oxygen consumption, with further improvements found when sodium phosphate supplementation was repeated. Cycling time trial performance tended to be better after sodium phosphate supplementation, but was not significantly so.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.