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Study note

Caffeine increases strength and power performance in resistance-trained females during early follicular phase.

PMID 32681596 (2020): caffeine — Time-trial performance, Time to exhaustion (study note for endurance athletes).

Updated Jul 22, 2026

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Study note • PMID 32681596

Caffeine increases strength and power performance in resistance-trained females during early follicular phase.

Scandinavian journal of medicine & science in sports • 2020 • DOI 10.1111/sms.13776
Open on PubMed

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

The effects of 4 mg.kg(-1) caffeine ingestion on strength and power were investigated for the first time, in resistance-trained females during the early follicular phase utilizing a randomized, double-blind,… (randomized trial; n=3 trained athletes).

The abstract doesn’t indicate a 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: The effects of 4 mg.kg(-1) caffeine ingestion on strength and power were investigated for the first time, in resistance-trained females during the early follicular phase utilizing a randomized, double-blind,…
  • • The abstract doesn’t indicate a clear change in Time-trial performance, Time to exhaustion under the tested conditions.
  • • Population: n=3 trained athletes.
  • • Protocol cues (title/abstract): 4 mg • 60 minutes • 72 hours.

Protocol

Protocol (as reported)

  • • Intervention/exposure: caffeine (vs placebo).
  • • Dose/time/duration cues in abstract/title: 4 mg • 60 minutes • 72 hours.
  • • 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 (n=3 trained athletes) 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 (double-blind, placebo-controlled).
  • • Population: n=3 trained athletes.
  • • Comparator: placebo.
  • • Outcomes measured: Time-trial performance, Time to exhaustion.
  • • Protocol cues mentioned: 4 mg • 60 minutes • 72 hours.
  • • Source: PubMed PMID 32681596 (2020) — Scandinavian journal of medicine & science in sports.

Results excerpt

What the abstract reports

“Caffeine significantly improved squat (4.5 +/- 1.9%, effect size [ES]: 0.25) and bench press 1RM (3.3 +/- 1.4%, ES: 0.20), and squat (15.9 +/- 17.9%, ES: 0.31) and bench press RTF (9.8 +/- 13.6%, ES: 0.31), compared to placebo.”

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.

Keep the outcome and population exact

This randomized trial studied an acute caffeine dose and strength or repetition performance in resistance-trained women during a defined menstrual-cycle phase. It did not test endurance time trials or time to exhaustion, despite those automated outcome labels.

The conservative training takeaway is not “take caffeine for every session.” It is that an acute response observed in a specific resistance-training protocol may not transfer to HYROX racing, running, cycling or an individual's tolerance. If caffeine is already appropriate, test a familiar amount well before competition and record sleep, anxiety, gastrointestinal and cardiovascular response.

Confirm participants, dose and outcomes in the PubMed record. Caffeine can interact with health conditions, pregnancy, medication and sleep. Seek individualized guidance where relevant and do not combine unfamiliar stimulant products.

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