No Ergogenic Effect of Caffeine or Sodium Bicarbonate on Resistance Exercise Performance: A Double-Blind Crossover Study with Sex-Based Analysis
Bibliographic record
Abstract
Caffeine, a nervous system stimulant, and sodium bicarbonate, a metabolic buffer, have been shown to improve performance in high-intensity, particularly aerobic exercises. This randomized, double-blind, placebo-controlled, crossover study compared the effects of caffeine and sodium bicarbonate on chest press (CP) and knee extension (KE) performance. Twelve resistance-trained young adults (seven females) completed three testing sessions during which they consumed caffeine (0.003g/kg body weight), sodium bicarbonate (0.3 g/kg body weight), or placebo from 120-60 minutes prior to testing. Testing consisted of 6 sets of CP and KE for as many repetitions as possible at 70% of the participants’ 1-repetition maximum load. A 60-second recovery between sets, and 2-minute recovery was allocated between exercises. Blood pressure and blood lactate were recorded pre-, mid-, and post-test. Heart rate, ratings of perceived exertion (RPE), repetitions, and electromyography (EMG) were recorded for every set. No significant differences were found for any condition for RPE, EMG, and KE repetitions. Some evidence showed increased CP repetitions with sodium bicarbonate (7.42; 95%CI: 6.8-7.9), versus caffeine (6.7; 95%CI: 6.1-7.3) and control (7.1; 95%CI: 6.4-7.6) conditions. However, post-hoc analysis did not achieve significance. Diastolic blood pressure was significantly (p=0.03) greater with caffeine (79.2 mmHg; 95%CI: 74.6-83.7) than with sodium bicarbonate (72.7 mmHg; 95%CI: 67.5-77.9) and control (74.5 mmHg; 95%CI: 71.7-77.3). Females had significantly lower blood lactate measurements, higher CP repetitions, and lower heart rates, despite similar resting heart rates between sexes. Caffeine or sodium bicarbonate did not provide ergogenic effects on CP or KE resistance training performance.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".