Study note • PMID 40478455
Acute caffeine intake improves muscular strength, power, and endurance performance, reversing the time-of-day effect regardless of muscle activation level in resistance-trained males: a randomized controlled trial.
How to use this page
This note summarizes one study record. Check the participants, methods, results, and limitations before applying it to training.
- • Design signal: randomized trial.
- • Population relevance: athlete/trained context.
- • Consistency: single-study evidence.
- • Practical recommendation depends on tolerance, context, and whether it protects training consistency.
ELI5
In plain language
INTRODUCTION: This study examined the effects of acute caffeine intake on muscular electrical activity during strength, power, and endurance performance tests at different times of day in bench press… (randomized trial; trained participants).
The abstract doesn’t indicate a clear change in Time-trial performance 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: INTRODUCTION: This study examined the effects of acute caffeine intake on muscular electrical activity during strength, power, and endurance performance tests at different times of day in bench press…
- • The abstract doesn’t indicate a clear change in Time-trial performance under the tested conditions.
- • Population: trained participants.
- • Protocol cues (title/abstract): 3 mg/kg • 60 min.
Protocol
Protocol (as reported)
- • Intervention/exposure: caffeine (vs placebo).
- • Dose/time/duration cues in abstract/title: 3 mg/kg • 60 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 may help, and who should be cautious
Who it helps
- • Athletes similar to the study population (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 be cautious
- • 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 (placebo-controlled).
- • Population: trained participants.
- • Comparator: placebo.
- • Outcomes measured: Time-trial performance, Time to exhaustion.
- • Protocol cues mentioned: 3 mg/kg • 60 min.
- • Source: PubMed PMID 40478455 (2025) — European journal of applied physiology.
Results excerpt
What the abstract reports
“At 25%1RM, caffeine counteracts morning performance decline in bench press (10-11%, P = 0.001, g = 2.62-1.68) and back squat (8-11%, P = 0.010-0.003, g = 2.22-1.64).”
Note: excerpts are short; for full context, read the paper.
Limits
Limitations and 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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