Author(s): VAN HANSEWYCK, J., BOONE, J., VERMEIRE, K., CAEN, K., Institution: GHENT UNIVERSITY, Country: BELGIUM, Abstract-ID: 1988

INTRODUCTION:
Sodium bicarbonate (HCO3-) supplementation can enhance high-intensity performance by increasing extracellular buffering capacity. In the omnium, several high-intensity efforts are performed within the same day with short recovery periods, so maintaining elevated [HCO3-] throughout the event may help sustain performance. Because athletes differ widely in how quickly they absorb and respond to HCO3- supplementation, understanding individual kinetics is essential for selecting the most effective timing and dosage. This case study aimed to explore HCO3- kinetics following supplementation in two elite female track cyclists during an omnium race simulation.
METHODS:
Two elite female track cyclists completed a laboratory simulation of an omnium event, in which three out of four races were simulated. Each simulation included a 10-min high-intensity effort consisting of short intervals (30 s work / 30 s recovery), with 1 hour of rest between efforts. Both athletes ingested a single dose of Maurten HCO3- (~0.30 g/kg). Athlete 1 consumed the dose 60 min before the first effort, whereas Athlete 2 took it 90 min before the start. The timing reflected each athlete's habitual race-day protocol, including their standard warm-up. Capillary blood samples were collected at baseline before supplementation, before warm-up, and before and 10 min after each simulated race. The final sample was taken prior to the virtual fourth race. Samples were analyzed using a blood gas analyzer to determine [HCO3-], pH, pCO2, and lactate concentrations.
RESULTS:
Both athletes demonstrated a significant increase in [HCO3-] following supplementation, with notable differences in magnitude and timing of peak values. Athlete 1 showed a rapid rise from baseline, achieving a peak increase of +8.3 mmol/L before the third race effort. Athlete 2 exhibited slower absorption kinetics, with a maximal increase of +6.4 mmol/L occurring prior to the second race. Declines in [HCO3-] and pH appeared after the second and third efforts, in line with higher lactate concentrations after these bouts. As lactate decreased during recovery, [HCO3-] rose again and returned close to peak values before the next simulated race. Athlete 1 did not fully recover [HCO3-] after the third effort, resulting in lower pre-race levels before the virtual fourth race compared with earlier efforts. Nevertheless, both athletes finished with [HCO3-] well above baseline.
CONCLUSION:
This case study highlights interindividual variability in HCO3- absorption kinetics. Athlete 1 appears to benefit from ingestion ~90 min before competition, whereas Athlete 2 requires ingestion at least 120 min beforehand to achieve optimal buffering early in the omnium. These findings underscore the importance of individualized dosing and timing protocols, and future research should continue refining frameworks for high-performance settings.