The Study
Caffeine ingestion attenuates diurnal variation of lower-body ballistic performance in resistance-trained women
This study gave women caffeine and measured how high they could jump at different times of day. It found that caffeine helped them jump a little higher in the morning, but only for one type of jump. We can't say caffeine definitely causes this because we didn't see the full study, and only 15 women took part.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if drinking caffeine before exercise helps women who lift weights jump higher, especially in the morning when they're usually weaker.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 537 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The jump improvement in the morning was enough to match their afternoon performance, which could matter for athletes training early.
- 2Caffeine made women jump 3.1% higher in the morning and 1.6% higher in the afternoon.
- 3It did not help them throw the bench press faster, lift heavier weights, or do more repetitions.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Sport Science
Year
2022
Authors
Lidia Robles-González, Mauricio Ramírez Maldonado, Juan Carlos Alcalá-Escamilla, L. Jurado-Fasoli, Sergio Miras-Moreno, M. Soriano, A. García-Ramos, J. R. Ruiz, F. Amaro-Gahete
Related Content
Claims (5)
Caffeine improves physical performance more in the morning than in the afternoon because core body temperature starts lower in the morning and rises more after caffeine intake.
Drinking caffeine in the morning increases core body temperature and enhances physical performance. Regular caffeine use over time does not affect muscle growth because the body adapts to its presence.
Resistance-trained women produce higher jump heights and faster barbell velocities in the afternoon than in the morning, indicating that lower-body explosive performance varies with time of day.
In women who regularly train with weights, taking 3 mg of caffeine per kilogram of body weight before testing increases vertical jump height in the morning by 3.1% and in the afternoon by 1.6%, but does not change peak speed, maximum strength, or endurance during bench press throws.
Taking 3 mg of caffeine per kilogram of body weight does not increase peak speed during bench press throws, maximum strength in squats or bench presses, or endurance during strength exercises in women who regularly train with weights, no matter when they take it.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.