Acute Sodium Bicarbonate Supplementation Improves Repeated Sprint Ability in Recreational Female Football Players: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Repeated sprint ability (RSA) is a critical component of football, yet high-intensity effort leads to H+ accumulation. Sodium bicarbonate (SB) is an effective buffering agent, though evidence supporting its use among female football players remains limited. We conducted a randomized, double-blind, placebo-controlled, crossover trial (NCT06098794) to examine the acute effects of SB on RSA in recreational female football players. Eleven athletes completed two RSA sessions on a cycle ergometer under SB and placebo (PL) conditions. Each session involved 3 sets of 6 maximal 6 s sprints performed every 30 s, with a 5 min recovery between sets. Participants ingested 0.2 g·kg−1 of the supplement 2 h prior to testing and 0.1 g·kg−1 1 h before the session. The results showed that SB induced a greater blood lactate accumulation (SB: 14.0 ± 4.32 vs. PL: 10.9 ± 3.55 mmol·L−1, p = 0.010) and a greater elimination of CO2 through breathing (p = 0.038), while maintaining muscle oxygenation. These physiological responses were accompanied by improved performance, as SB prevented a decline in mean power output from the first to the second set (SB: +1.4% vs. PL: −3.7%) and reduced the post-test drop in jump height (SB: −2.0% vs. PL: −8.2%). These findings suggest that SB supplementation may be useful to reduce muscular acidosis and fatigue in recreational female football players.