Effects of Single Sodium Bicarbonate Supplementation on National-Level Finswimming Performance

Inclusion Criteria: 1. Member of a wider national selection in finswimming (junior or senior level) 2. Regular participation in competitive finswimming training (≥4 sessions per week) 3. Age between 15 and 30 years 4. Absence of chronic illness or injury 5. No use of medications or dietary supplements during the study period 6. Signed informed consent (for minors, also signed by a legal guardian) Exclusion Criteria: 1. History of gastrointestinal disorders affecting supplement tolerance 2. Presence of cardiovascular, metabolic, or musculoskeletal disorders 3. Current illness or acute infection 4. Regular use of substances that may interfere with acid-base balance 5. Refusal to comply with pre-test restrictions (e.g., 48 hours without training)