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Study note

Effects of caffeine supplementation on muscle endurance, maximum strength, and perceived exertion in adults submitted to strength training: a systematic review and meta-analyses.

PMID 32551869 (2021): caffeine — Time-trial performance, Time to exhaustion (study note for endurance athletes).

Updated Jul 22, 2026

Read the study note

Study note • PMID 32551869

Effects of caffeine supplementation on muscle endurance, maximum strength, and perceived exertion in adults submitted to strength training: a systematic review and meta-analyses.

Critical reviews in food science and nutrition2021 • DOI 10.1080/10408398.2020.1781051

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: systematic review / meta-analysis.
  • Population relevance: mixed/unclear athlete specificity.
  • Consistency: synthesis evidence present.
  • Practical recommendation depends on tolerance, context, and whether it protects training consistency.

ELI5

In plain language

This study aimed to determine the effects of caffeine supplementation on muscle endurance, maximum strength, and ratings of perceived exertion (RPE) in individuals undergoing strength training with external resistance exercises. (systematic review / meta-analysis; participants).

In this systematic review / meta-analysis, the abstract doesn’t find a clear benefit for Time-trial performance, Time to exhaustion. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • Study question: This study aimed to determine the effects of caffeine supplementation on muscle endurance, maximum strength, and ratings of perceived exertion (RPE) in individuals undergoing strength training with external resistance exercises.
  • In this systematic review / meta-analysis, the abstract doesn’t find a clear benefit for Time-trial performance, Time to exhaustion.
  • Population: participants.
  • Protocol cues: abstract may omit dose/timing; use the full paper to replicate accurately.

Protocol

Protocol (as reported)

  • Intervention/exposure: caffeine.
  • Dose/time/duration: abstract doesn’t include enough detail; use the full paper’s methods section.
  • 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 (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: systematic review / meta-analysis (double-blind, placebo-controlled).
  • Population: participants.
  • Outcomes measured: Time-trial performance, Time to exhaustion.
  • Source: PubMed PMID 32551869 (2021) — Critical reviews in food science and nutrition.

Results excerpt

What the abstract reports

More investigations are needed to clarify the contradictions in its effects regarding lower-body exercises.

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).
  • Reviews and consensus statements mix protocols and populations; recommendations may not match your exact constraints.
  • 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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