Study note • PMID 39246027
Caffeine, but not paracetamol (acetaminophen), enhances muscular endurance, strength, and power.
Worth trying if it fits your goal and context.
ELI5
In plain language
BACKGROUND: Caffeine is one of the most popular ergogenic aids consumed by athletes. (randomized trial; n=29 trained participants).
Results section: no clear change in Time-trial performance, Time to exhaustion under the tested conditions. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.
Takeaways
What the abstract suggests
- • Study question: BACKGROUND: Caffeine is one of the most popular ergogenic aids consumed by athletes.
- • Results section: no clear change in Time-trial performance, Time to exhaustion under the tested conditions.
- • Population: n=29 trained participants.
- • Protocol cues (full paper): 3 mg/kg • 1500 mg • 1000 mg • 24 hours • 45 minutes • 3 minutes.
Protocol
Protocol (as reported)
- • Intervention/exposure: caffeine (vs placebo).
- • Dose/time/duration cues found in the full paper: 3 mg/kg • 1500 mg • 1000 mg • 24 hours • 45 minutes • 3 minutes • 1 minute • 1 min.
- • Outcomes: Time-trial performance, Time to exhaustion.
- • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.
Fit
Who it helps, and who should skip it
Who it helps
- • Athletes similar to the study population (n=29 trained participants) working on supplements.
- • Athletes who can measure Time-trial performance, Time to exhaustion with a repeatable workout or time-trial effort.
Who should skip
- • If you have symptoms or conditions that make the intervention risky, get professional guidance.
- • If you’re near race day and can’t safely test, defer the experiment.
Methods
What the study actually did
- • Design: randomized trial (randomized, double-blind, placebo-controlled, crossover).
- • Population: n=29 trained participants.
- • Comparator: placebo.
- • Outcomes measured: Time-trial performance, Time to exhaustion.
- • Protocol cues mentioned: 3 mg/kg • 1500 mg • 45 min.
- • Source: PubMed PMID 39246027 (2024) — Journal of the International Society of Sports Nutrition.
Full paper
What the full paper adds
- • Design features (paper): randomized, double-blind, placebo-controlled, crossover.
- • Participants (paper): n=29 trained participants.
- • More protocol detail (paper): 3 mg/kg • 1500 mg • 1000 mg • 24 hours • 45 minutes • 3 minutes • 1 minute • 1 min.
- • Results section: no clear change in Time-trial performance, Time to exhaustion under the tested conditions.
Results excerpt
What the abstract reports
“Compared to placebo, isolated caffeine ingestion increased the number of repetitions performed in the bench press (p = 0.005; d = 0.42).”
Note: excerpts are short; for full context, read the paper.
Limits
Limitations & bias
- • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
- • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
- • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
- • This is performance information, not medical advice.
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Caffeine for endurance performance: a practical protocol
Evidence-informed protocol: Caffeine for endurance performance: a practical protocol. Practical steps, who it helps, and what to watch out for.
Time-trial performance research for endurance athletes
Practical performance outcome used in many studies: closer to racing than lab-only metrics.
Time to exhaustion research for endurance athletes
A lab outcome that can still guide training: it often tracks fatigue resistance.