Effect of Beta alanine and sodium bicarbonate supplementation on repeated-sprint performance

This study aimed to investigate if combining beta alanine (BA) and sodium bicarbonate (NaHCO3) supplementation could lead to enhanced repeated-sprint performance in team-sport athletes, beyond what is possible with either supplement alone. Participants (n = 24) completed duplicate trials of a repeated-sprint test (3 sets; 6 × 20 m departing every 25 seconds, 4 minutes active recovery between sets) and were then allocated into 4 groups as follows: BA only (n = 6; 28 days BA, acute sodium chloride placebo); NaHCO3 only (n = 6; 28 days glucose placebo, acute NaHCO3); BA/NaHCO3 (n = 6; 28 days BA, acute NaHCO3); placebo only (n = 6; 28 days glucose placebo, acute sodium chloride placebo), then completed duplicate trials postsupplementation. Sodium bicarbonate alone resulted in moderate effect size (d = 0.40-0.71) and "likely" and "very likely" benefit for overall total sprint times (TST) and for each individual set and for first sprint (sets 2 and 3) and best sprint time (sets 2 and 3). Combining BA and NaHCO3 resulted in "possible" to "likely" benefits for overall TST and for sets 2 and 3. First sprint (set 3) and best sprint time (sets 2 and 3) also showed "likely" benefit after this trial. The BA and placebo groups showed no differences in performance after supplementation. In conclusion, these results indicate that supplementation with acute NaHCO3 improved repeated-sprint performance more than either a combination of NaHCO3 and BA or BA alone.