ECSS Paris 2023: CP-PN03
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.
Read CV Jutte Van hansewyckECSS Paris 2023: CP-PN03
INTRODUCTION: Tart cherries (TC) possess anti-inflammatory and antioxidative properties and are a popular nutritional strategy for exercise recovery. However, since exercise-induced oxidative stress and inflammation are thought to contribute to the adaptation process, TC supplementation might reduce adaptive responses. The repeated bout effect (RBE), the protective effect following eccentric exercise, serves as a model to understand acute adaptation. This study examined whether TC supplementation attenuates the adaptive response. METHODS: Twenty-one recreationally active participants performed two bouts of 40 maximal lengthening contractions of the elbow flexors, separated by two weeks. Participants were randomly assigned to receive either freeze-dried TC powder or a placebo (11 TC, 10 placebo) for 8 days in total, with the first exercise bout on day 5. Maximal voluntary contraction (MVC), muscle soreness (DOMS), pain pressure threshold (PPT), range of movement (ROM), upper arm limb girth and creatine kinase (CK) were assessed at 24, 48 and 72 h post-exercise. RESULTS: TC did not reduce muscle damage markers after the first bout. Both groups demonstrated RBE for DOMS, PPT, and CK in bout 2. The placebo group showed faster MVC and ROM recovery in bout 2, while the TC group showed no differences between bouts for MVC, ROM, or girth. At 24 h post-bout 2, MVC recovered to 96±17% in placebo and 83±15% in TC. CONCLUSION: This is the first study investigating powdered TC’s effect on acute adaptation following muscle damage. TC did not affect symptoms of pain, ROM and CK responses but showed evidence of attenuated adaptation in the repeated bout for MVC and limb girth.
Read CV Emma SquiresECSS Paris 2023: CP-PN03
INTRODUCTION: Caffeine is one of the most widely consumed bioactive compounds globally, primarily ingested through coffee, tea, and caffeinated beverages. Its ergogenic potential is well established, yet the literature remains inconsistent regarding its effects on substrate utilization, particularly at low doses and during low-intensity exercise. While high caffeine doses (~5 mg/kg) are commonly studied, recent evidence suggests that much lower doses may elicit meaningful physiological effects. Importantly, few studies have examined ecologically valid doses equivalent to everyday coffee consumption or explored sex-specific metabolic responses. This secondary analysis investigates whether a low caffeine dose (135 mg), equivalent to a double espresso, enhances fat oxidation during low-intensity endurance exercise. METHODS: We conducted a sex-stratified secondary analysis of a randomized, single-blind, crossover study involving 29 healthy adults (15 men, 14 women). Participants consumed 500 ml of either plain water, water with 135 mg anhydrous caffeine, or yerba mate following a 12-hour fast. After a 40-minute absorption period, participants completed graded cycling exercise from 20W to 80W in 20W increments. Respiratory quotient (RQ), energy expenditure, heart rate, and delta efficiency were measured using indirect calorimetry. Given the similar caffeine and polyphenol content and near-identical metabolic responses of the yerba mate treatments, these were combined for analysis. Changes in RQ from rest to each workload (ΔRQ) were calculated to quantify shifts in substrate utilization. RESULTS: In men, caffeine produced the lowest RQ across all workloads and the smallest increase from rest to 80W (ΔRQ = 0.099), compared with water (ΔRQ = 0.114) and yerba mate (ΔRQ = 0.112). Post-hoc analyses revealed significantly lower RQ values for caffeine at 60W and 80W (p < 0.05), indicating enhanced fat oxidation and attenuation of the shift toward carbohydrate utilization. In women, no consistent or statistically significant differences in RQ or ΔRQ were observed between interventions. CONCLUSION: This analysis demonstrates that the significant drink × intensity × sex interaction reported in the original study was specifically driven by caffeine’s metabolic effects in men. Consistent with emerging evidence that low caffeine doses can exert meaningful ergogenic effects, our findings extend this concept to substrate utilization during low-to-moderate intensity exercise using an ecologically valid dose equivalent to a double espresso. A 135 mg caffeine intake significantly enhanced fat oxidation in men but not in women, underscoring the importance of sex-specific analyses and supporting the metabolic relevance of low-dose, real-world caffeine consumption during everyday physical activity. References Grgic J. Nutrition. 2022;97. Zaki SB et al. Current Developments in Nutrition. 2025 (accepted).
Read CV Rami ElhusseiniECSS Paris 2023: CP-PN03