Evidence map›Paper›PMID 29527137›Full record

SynthesisJournal of the International Society of Sports Nutrition2018

Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis.

Jozo Grgic, Eric T Trexler, Bruno Lazinica, Zeljko Pedisic

3 registry-linked trialsOpen access · goldAbstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Journal of the International Society of Sports Nutrition, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 3 registered trials, which are not on this map. Cited by 182 papers, 34 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
182citing papers in PubMed, 34 pooled it
41.8field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT05916352 nacompletednot on this mapstarted 2022, after this paper: background citation

The Effect of Caffeine Supplementation on Blood Lactate Level, Performance and Post-Training Fatigue in Elite Basketball Players

TypeinterventionalSponsorCyprus International UniversityRan2022 to 2023Enrolled50ConditionsSportive Performance, CaffeineArmsCaffeine Supplement
NCT07410195 nacompletednot on this mapstarted 2026, after this paper: background citation

Study of Different Caffeine Supplementation Strategies on Resistance Training-Induced Adaptations

TypeinterventionalSponsorIstanbul University - CerrahpasaRan2026 to 2026Enrolled120ConditionsMuscle Hypotrophy, Exercise Performance, Muscle Strength, AdaptationArmsCaffeine (Constant Daily Dose), Caffeine (Escalating Dose), Caffeine (Training Days Only), placebo capsule
NCT07520864 nacompletednot on this mapstarted 2026, after this paper: background citation

Is Caffeine the Secret Ingredient for Elite Weightlifting Performance? It Helps-But Don't Expect Miracles

TypeinterventionalSponsorUniversidad Pontificia ComillasRan2026 to 2026Enrolled14ConditionsAthletesArmsPlacebo, Caffeine
3 · Its place in the literature

Who cites it

182 citing papers in PubMed, 34 syntheses or guidelines pooled it, 339 citations in OpenAlex.

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122 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors at 3 institutions in 3 countries.

Jozo Grgic1Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.
Eric T Trexler2Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC USA.
Bruno LazinicaFaculty of Education, Department of Kinesiology, J.J. Strossmayer University, Osijek, Croatia.
Zeljko Pedisic1Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.
Victoria University · AUUniversity of North Carolina at Chapel Hill · USUniversity of Osijek · HR

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundCaffeine is commonly used as an ergogenic aid. Literature about the effects of caffeine ingestion on muscle strength and power is equivocal. The aim of this systematic review and meta-analysis was to summarize results from individual studies on the effects of caffeine intake on muscle strength and power.

methodsA search through eight databases was performed to find studies on the effects of caffeine on: (i) maximal muscle strength measured using 1 repetition maximum tests; and (ii) muscle power assessed by tests of vertical jump. Meta-analyses of standardized mean differences (SMD) between placebo and caffeine trials from individual studies were conducted using the random effects model.

resultsTen studies on the strength outcome and ten studies on the power outcome met the inclusion criteria for the meta-analyses. Caffeine ingestion improved both strength (SMD = 0.20; 95% confidence interval [CI]: 0.03, 0.36;

conclusionThe meta-analyses showed significant ergogenic effects of caffeine ingestion on maximal muscle strength of upper body and muscle power. Future studies should more rigorously control the effectiveness of blinding. Due to the paucity of evidence, additional findings are needed in the female population and using different forms of caffeine, such as gum and gel.

Indexed as

AthletesCaffeineHumansMuscle, SkeletalMuscle StrengthPerformance-Enhancing SubstancesSports Nutritional Physiological PhenomenaCaffeinePerformance-Enhancing SubstancesData synthesisErgogenic aidPerformancePower

Identifiers

PMID29527137
PMCPMC5839013
OpenAlexW2793103700

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.