The effect of sodium phosphate supplementation on repeated sprint performance in team sport athletes, in a laboratory based test

The aim of this study was to determine whether a four day supplementation of SP has any effect on repeated sprint performance in a laboratory based test. Eight recreationally trained team sport athletes (V̇O2max 41.4 ± 4.1 ml . kg . min-1) completed two familiarisation/pre-assessment sessions and three performance trials. During the performance trials participants completed a repeated sprint test consisting of 12 x 6 second sprints interspersed with 30 seconds passive of rest on an electromagnetically braked cycle ergometer. Following the completion of the baseline trial, participants were give either SP (50 mg . kg . free fat mass (ffm)-1) or placebo (maltodextrin = 2400 mg) per day for four days using a randomised, double blinded crossover design. A 15 day washout period separated the two supplement trials. SP was found to have no significant effect on peak power, mean power, total work done and performance decrement score compared to baseline and placebo trials (p > 0.05). Furthermore, SP was found to have no significant effect on oxygen consumed, tissue saturation or respiratory exchange ratio during the repeated sprint test (p > 0.05). Although, one minute post-test heart rate was found to be significantly lower in the SP trial compared to the placebo (mean difference = 8.13 bpm, p = 0.039, 95% CI = -15.796 - -0.454). In conclusion, SP was shown to have no effect on repeated sprint performance in team sport athletes, nor have any effect on physiological variables linked to the proposed mechanisms of SP.