Background:It has been suggested that localized skeletal muscle fatigue is linked to the body’s buffering capacity and, specifically, the ability to counteract H+ accumulation. Research has focused on inducing pre-exercise alkalosis in the form of an exogenous buffer. One of the most common is sodium bicarbonate (NaHCO3). Although the research findings regarding the efficacy of NaHCO3 supplementation remains inconclusive, the practice of soda loading is quite common, particularly in elite sports. One of the most difficult sports to quantify improvements through sodium bicarbonate loading, as evidenced by the limited research data, is swimming. Previous studies in this area have failed to report pre- and postswim acid–base status, have introduced lower-than-conventional NaHCO3 doses, or have combined the buffer with another supplement.

Hypothesis/purpose of study:To determine the influence of NaHCO3 (0.3 g/kg) standard supplementation on ergogenic potential and acid–base status in competitive, nonelite swimmers

Subjects:Six male (mean ± standard deviation: height 181.2 ± 7.2 cm, weight 80.3 ± 11.9 kg, maximal oxygen consumption [VO2max] 50.8 ± 5.5 mL/kg/min) and 8 female (height 168.8 ± 5.6 cm, weight 75.3 ± 10.1 kg, VO2max 38.8 ± 2.6 mL/kg/min) competitive, nonelite swimmers

Experimental design: Randomized counterbalanced, placebo-controlled, single-blind study

Treatments and protocol:All swimmers completed 2 trial conditions (NaHCO3 [BICARB] and NaCl placebo [PLAC]), each separated by 1 week. On each testing day, participants reported to the laboratory 4 hours postprandial to consume their prescribed drink (BICARB or PLAC). For the NaHCO3 trial, the buffer solution (0.3 g/kg) was diluted into 500 mL of a low calorie, flavored drink and consumed over a 15-minute period 2.5 hours before competition. For the placebo trials, 0.045 g/kg of NaCl was substituted for NaHCO3. After 2.5 hours postingestion, swimmers were paired according to ability and completed 8, 25-m, front crawl, maximal-effort sprints each separated by 5 seconds. Blood acid–base status was assessed preingestion and pre- and postswim via capillary finger sticks, and total swim time was calculated as a performance measure.