Trial reportPloS one2012
Caffeine ingestion reverses the circadian rhythm effects on neuromuscular performance in highly resistance-trained men.
Trial report in PloS one, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 40 papers, 2 of them syntheses that pooled 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.
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.
Who cites it
40 citing papers in PubMed, 2 syntheses or guidelines pooled it, 88 citations in OpenAlex.
- Effects of acute caffeine intake on muscular power during resistance exercise: a systematic review and meta-analysis.Frontiers in nutrition · 2025Pooled it
- Acute Effects of Caffeine Supplementation on Movement Velocity in Resistance Exercise: A Systematic Review and Meta-analysis.Sports medicine (Auckland, N.Z.) · 2020Pooled it
- Effects of Caffeine Ingestion on Morning Cognitive and Muscle Strength Measures in Males: A Standardized Approach.Nutrients · 2026Trial
- 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.European journal of applied physiology · 2025Trial
- Comparative effects of caffeine, beta-alanine, and their combination on mechanical, physiological, and perceptual responses to upper-body superset resistance training.European journal of applied physiology · 2025Trial
- Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial.The Journal of physiology · 2024Trial
- Trial
- Supplementation of caffeine and sodium bicarbonate together could not improve performance and performance-related factors in CrossFit participants: a randomized, double-blind, placebo-controlled study.Journal of the International Society of Sports Nutrition · 2023Trial
- Trial
- Effects of Short-Term Golden Root Extract (International journal of environmental research and public health · 2021Trial
- Caffeine-Induced Effects on Human Skeletal Muscle Contraction Time and Maximal Displacement Measured by Tensiomyography.Nutrients · 2021Trial
- Acute Beetroot Juice Supplementation Attenuates Morning-Associated Decrements in Supramaximal Exercise Performance in Trained Sprinters.International journal of environmental research and public health · 2021Trial
- The effects of a caffeine-like supplement, TeaCrine®, on muscular strength, endurance and power performance in resistance-trained men.Journal of the International Society of Sports Nutrition · 2019Trial
- Caffeine Supplementation Improves Anaerobic Performance and Neuromuscular Efficiency and Fatigue in Olympic-Level Boxers.Nutrients · 2019Trial
- Trial
- Caffeinated Gel Ingestion Enhances Jump Performance, Muscle Strength, and Power in Trained Men.Nutrients · 2019Trial
- The effect of CYP1A2 genotype on the ergogenic properties of caffeine during resistance exercise: a randomized, double-blind, placebo-controlled, crossover study.Irish journal of medical science · 2019Trial
- Effects of Caffeine Supplementation on Power Performance in a Flywheel Device: A Randomised, Double-Blind Cross-Over Study.Nutrients · 2019Trial
- Effects of two pre-workout supplements on concentric and eccentric force production during lower body resistance exercise in males and females: a counterbalanced, double-blind, placebo-controlled trial.Journal of the International Society of Sports Nutrition · 2017Trial
- The effects of supplementation with P-Synephrine alone and in combination with caffeine on resistance exercise performance.Journal of the International Society of Sports Nutrition · 2015Trial
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeTo investigate whether caffeine ingestion counteracts the morning reduction in neuromuscular performance associated with the circadian rhythm pattern.
methodsTwelve highly resistance-trained men underwent a battery of neuromuscular tests under three different conditions; i) morning (10:00 a.m.) with caffeine ingestion (i.e., 3 mg kg(-1); AM(CAFF) trial); ii) morning (10:00 a.m.) with placebo ingestion (AM(PLAC) trial); and iii) afternoon (18:00 p.m.) with placebo ingestion (PM(PLAC) trial). A randomized, double-blind, crossover, placebo controlled experimental design was used, with all subjects serving as their own controls. The neuromuscular test battery consisted in the measurement of bar displacement velocity during free-weight full-squat (SQ) and bench press (BP) exercises against loads that elicit maximum strength (75% 1RM load) and muscle power adaptations (1 m s(-1) load). Isometric maximum voluntary contraction (MVC(LEG)) and isometric electrically evoked strength of the right knee (EVOK(LEG)) were measured to identify caffeine's action mechanisms. Steroid hormone levels (serum testosterone, cortisol and growth hormone) were evaluated at the beginning of each trial (PRE). In addition, plasma norepinephrine (NE) and epinephrine were measured PRE and at the end of each trial following a standardized intense (85% 1RM) 6 repetitions bout of SQ (POST).
resultsIn the PM(PLAC) trial, dynamic muscle strength and power output were significantly enhanced compared with AM(PLAC) treatment (3.0%-7.5%; p≤0.05). During AM(CAFF) trial, muscle strength and power output increased above AM(PLAC) levels (4.6%-5.7%; p≤0.05) except for BP velocity with 1 m s(-1) load (p = 0.06). During AM(CAFF), EVOK(LEG) and NE (a surrogate of maximal muscle sympathetic nerve activation) were increased above AM(PLAC) trial (14.6% and 96.8% respectively; p≤0.05).
conclusionsThese results indicate that caffeine ingestion reverses the morning neuromuscular declines in highly resistance-trained men, raising performance to the levels of the afternoon trial. Our electrical stimulation data, along with the NE values, suggest that caffeine increases neuromuscular performance having a direct effect in the muscle.
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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.