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Completed

NCT Number: NCT06610110

Caffeine, CYPA12 and Resistance Exercise

Introduction: Several studies have evaluated and confirmed the ergogenic effect of acute caffeine intake on sports performance, specifically on strength and power performance. However, it remains to be elucidated how CYP1A2 polymorphism influences the acute effects of caffeine on this type of exercise.

Objectives: The present study aims to analyze the effects of acute caffeine intake on muscular strength, power, and endurance performance according to CYP1A2 polymorphism in men and women.

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Key information

Conditions

CYP1A2 Polymorphism 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, Spain

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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) lower than 25 kg/m².
  • Physically active subjects (≥150 min/week of moderate exercise).
  • Healthy men and women without neurological, cardiometabolic, immunological, or physical conditions that prevent them from performing physical exercise.
  • Participants capable of performing the tests.

Exclusion criteria

  • History of neuromuscular, cardiac, or diseases that could affect liver or muscle metabolism.
  • Use of drugs or other stimulants that interfere with caffeine intake and intestinal absorption during the tests and study.
  • Body mass index (BMI) ≥ 25 kg/m².
  • Having undergone prolonged periods of forced physical inactivity during the 6 months prior to the study.
  • Performing strenuous exercise within 48 hours prior to the tests.
  • Failing to replicate the same food intake on the two experimental days.
  • Consuming caffeine after 6 PM on the day prior to training or testing.

Treatment and study plan

Caffeine

Dietary Supplement

Acute caffeine intake (3 mg/kg)

Placebo

Dietary Supplement

Placebo (3 mg/kg maltodextrin)

Primary outcomes

  1. cyp1a2 polymorphism

    Time frame: Before the beginning of the trial

    Using saliva sample and PCR

  2. Mean velocity at different %1RM

    Time frame: Through study completion, an average of 2 weeks

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

  3. Peak velocity at different %1RM

    Time frame: Through study completion, an average of 2 weeks

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

  4. Mean power output at different %1RM

    Time frame: Through study completion, an average of 2 weeks

    Measuring during bench press and back squat exercises.

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

    Time frame: Through study completion, an average of 2 weeks

    Measuring during bench press and back squat exercises.

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

    Time frame: Through study completion, an average of 2 weeks

    In bench press and back squat exercises

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

    Time frame: Through study completion, an average of 2 weeks

    In bench press and back squat exercises

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

    Time frame: Through study completion, an average of 2 weeks

    In bench press and back squat exercise

  9. Maximal Fat Oxidation Rate (MFO)

    Time frame: Through study completion, an average of 2 weeks

    g/min (MFO) using a metabolic chart.

  10. Resting Metabolic Rate (RMR)

    Time frame: Through study completion, an average of 2 weeks

    Kcal at rest (RMR) using a metabolic chart.

Secondary outcomes

  1. Mood state (tension, depression, anger, vigor, fatigue and confusion)

    Time frame: Through study completion, an average of 2 weeks

    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.

  2. Adverse effects

    Time frame: Through study completion, an average of 2 weeks

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

  3. handgrip and isometric mid-thigh pull tests

    Time frame: Through study completion, an average of 2 weeks

    N generated

  4. Vertical Jump (cm)

    Time frame: Through study completion, an average of 2 weeks

  5. Vertical Jump (power)

    Time frame: Through study completion, an average of 2 weeks

Sponsors and collaborators

Lead sponsor

Alberto Pérez-López

Other

Collaborators

  • University of Alcala

Registry information

Official study title

Influence of CYP1A2 on the Acute Effect of Caffeine Intake on Resistance Exercise

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Sep 24, 2024
Registry last updated
May 6, 2026

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.

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