Skip to main content
OpenTrials
Completed

NCT Number: NCT06606639

Reproducibility of Acute Caffeine Effect

Introduction: Various studies have evaluated and verified the ergogenic effect of acute caffeine intake on sports performance, specifically on strength and power performance. However, all experimental investigations designed so far have been based on the comparison of the "caffeine" and "placebo" conditions in a single trial, not considering the reproducibility and variability of caffeine in multiple trials.

Objectives: The present study aims to evaluate the reproducibility and replicability of the acute effect of caffeine intake on energy metabolism and the muscular production of force, power and endurance, according to sex (men vs women) and type of exercise ( bench press vs squat).

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Caffeine and Resistance Exercise

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Facultad de Medicina y Ciencias de la Salud. Universidad de Alcalá

Alcalá de Henares, Madrid, 28805, Spain

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age between ≥ 18 and ≤ 35 years.
  • Body Mass Index (BMI) < 25 kg/m².
  • Resistance-trained individuals (> 2 years of structured trained).
  • Healthy men and women without neurological, cardiometabolic, immunological, or physical conditions that prevent them from exercising.
  • Participants must be able to perform the tests described in the following section.

Exclusion criteria

  • History of neuromuscular diseases, heart diseases, or diseases that may affect liver or muscle metabolism.
  • Use of drugs, other stimulants or sport supplements that interfere with the the study dietary supplement.
  • Sedentary habits (<150 min/week of moderate exercise).
  • Having undergone prolonged periods of forced physical inactivity during the 6 months prior to the study.
  • Performing strenuous exercise during the 48 hours prior to the tests.
  • Failure to replicate the same food intake on the two days of the experiments.
  • Consuming caffeine or any other stimulant after 6 pm the day before the training or tests, to avoid headaches, discomfort, or lethargy among regular caffeine consumers.

Treatment and study plan

Caffeine

Dietary Supplement

acute caffeine intake (3 mg/kg)

Placebo

Dietary Supplement

Acute placebo intake (3 mg/kg of maltodextrin)

Primary outcomes

  1. Mean velocity at different %1RM

    Time frame: Through study completion, an average of 4 weeks

    Measuring bar mean velocity desplacement during bench press and back squat exercises.

  2. Peak velocity at different %1RM

    Time frame: Through study completion, an average of 4 weeks

    Measuring bar peak velocity and time to reach peak velocity of bar desplacement during bench press and back squat exercises.

  3. Mean power output at different %1RM

    Time frame: Through study completion, an average of 4 weeks

    Measuring during bench press and back squat exercises.

  4. Peak power output and time to reach peak power output at different %1RM

    Time frame: Through study completion, an average of 4 weeks

    Measuring during bench press and back squat exercises.

  5. Number of repetitions performed in 1 set at 65%1RM until task failure

    Time frame: Through study completion, an average of 4 weeks

    In bench press and back squat exercises

  6. Bar velocity deplacement performed in 1 set at 65%1RM until task failure

    Time frame: Through study completion, an average of 4 weeks

    In bench press and back squat exercises

  7. Power output generated in 1 set at 65%1RM until task failure

    Time frame: Through study completion, an average of 4 weeks

    In bench press and back squat exercise

  8. Resting Metabolic Rate (RMR)

    Time frame: Through study completion, an average of 4 weeks

    Kcal at rest measuring (RMR) using a metabolic chart.

  9. Maximal Fat Oxidation Rate (MFO)

    Time frame: Through study completion, an average of 4 weeks

    g/min (MFO) using a metabolic chart.

Secondary outcomes

  1. Physical activity (METs-min/wk)

    Time frame: Through study completion, an average of 4 weeks

    Using IPAQ

  2. Dietary (g/kg of macronutrients)

    Time frame: Through study completion, an average of 4 weeks

    Using 24-total recall

  3. Mood state

    Time frame: Through study completion, an average of 4 weeks

    Mood. Participants graded a set of 29 items related to the mood on a Likert scale from 0 (not at all) to 4 (extremely) in reply to the question;How do you feel at this moment?; to assess six scales: tension, depression, anger, vigor, fatigue and confusion.

  4. Adverse effects

    Time frame: Through study completion, an average of 4 weeks

    Adverse effects. perception of power, endurance, energy and exertion, as well as heart, muscular and gastrointestinal discomfort.

  5. Fat mass

    Time frame: Through study completion, an average of 4 weeks

    Using electrical bioimpedance (kg and % of body mass)

  6. Fat-free mass

    Time frame: Through study completion, an average of 4 weeks

    Using electrical bioimpedance (kg and % of body mass)

Sponsors and collaborators

Lead sponsor

University of Alcala

Other

Registry information

Official study title

Reproducibility of the Acute Effect of Caffeine on Energy Metabolism and Muscular Strength, Power and Endurance Performance

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Sep 23, 2024
Registry last updated
May 25, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.