Evidence map›Paper›PMID 33322129›Full record

Trial reportNutrients2020

Placebo Effect of Caffeine on Maximal Strength and Strength Endurance in Healthy Recreationally Trained Women Habituated to Caffeine.

Aleksandra Filip-Stachnik, Michal Krzysztofik, Magdalena Kaszuba, Agata Leońska-Duniec, Wojciech Czarny, Juan Del Coso, Michal Wilk

Open access · goldAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Nutrients, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 15 papers, 4 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
15citing papers in PubMed, 4 pooled it
0.9field-weighted citation impact, top 25% 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.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

15 citing papers in PubMed, 4 syntheses or guidelines pooled it, 15 citations in OpenAlex.

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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

7 authors at 4 institutions in 2 countries.

Aleksandra Filip-StachnikInstitute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education in Katowice, 40-065 Katowice, Poland.ORCID 0000-0003-2008-6158
Michal KrzysztofikInstitute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education in Katowice, 40-065 Katowice, Poland.ORCID 0000-0003-2797-8431
Magdalena KaszubaInstitute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education in Katowice, 40-065 Katowice, Poland.
Agata Leońska-DuniecFaculty of Physical Education, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland.ORCID 0000-0001-6787-3760
Wojciech CzarnyCollege of Medical Sciences, Institute of Physical Culture Studies, University of Rzeszow, 35-959 Rzeszow, Poland.ORCID 0000-0001-9481-7609
Juan Del CosoCentre for Sport Studies, Rey Juan Carlos University, 28942 Fuenlabrada, Spain.ORCID 0000-0002-5785-984X
Michal WilkInstitute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education in Katowice, 40-065 Katowice, Poland.ORCID 0000-0001-5799-6337
Akademii Wychowania Fizycznego im. Jerzego Kukuczki w Katowicach · PLGdansk University of Physical Education and Sport · PLUniversidad Rey Juan Carlos · ESUniversity of Rzeszów · PL

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundBy using deceptive experimental designs, several investigations have observed that trained individuals may increase their performance when told they were given caffeine, when in fact they received a placebo (i.e., the placebo effect of caffeine). However, most of these investigations on the placebo effect of caffeine used individuals with low caffeine consumption or did not report habitual caffeine consumption, especially in studies analyzing resistance-based exercise. Hence, it is unknown if habitual caffeine consumers benefit from the placebo effect of caffeine on exercise performance. Thus, the aim of the present study was to analyze the placebo effect of caffeine on maximal strength and strength-endurance performance during the bench press exercise (BP) in women with mild-moderate daily consumption of caffeine.

methodsThirteen resistance-trained women (BP one-repetition maximum (1RM) = 40.0 ± 9.7 kg) habituated to caffeine (4.1 ± 1.7 mg/kg/day) completed a deceptive randomized experimental design with two experimental trials. On one occasion, participants were told that they would receive 6 mg/kg of caffeine but received a placebo (PLAC), and on other occasions, participants did not receive any substance and were told that this was a control situation (CONT). In each experimental trial, participants underwent a 1RM BP test and a strength-endurance test consisting of performing the maximal number of repetitions at 50% of their 1RM.

resultsIn comparison to CONT, PLAC did not enhance 1RM (40.0 ± 10.5 kg vs. 41.0 ± 9.5 kg, respectively;

conclusionInforming participants that they were given caffeine, when in fact they received a placebo, did not modify any performance variable measured in this investigation. Thus, the use of the placebo effect of caffeine seemed an ineffective strategy to enhance muscle strength and strength endurance during the BP exercise in women with mild-moderate consumption of caffeine.

Indexed as

AdultCaffeineCentral Nervous System StimulantsCross-Over StudiesFemaleHumansMuscle StrengthPhysical EndurancePlacebo EffectYoung AdultCaffeineCentral Nervous System Stimulantsbelief effectsergogenic aidsmuscle performancepsychological advantagesresistance exercise

Identifiers

PMID33322129
PMCPMC7763627
OpenAlexW3111170349

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

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.