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Completed

NCT Number: NCT06610123

Caffeine, CYPA12 and Resistance Training

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 prolonged effects of caffeine on this type of exercise.

Objectives: The present study aims to analyze the prolonged effects of caffeine intake on neuromuscular adaptations to resistance training according to CYP1A2 polymorphism in men and women.

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Key information

Conditions

CYP1A2 Polymorphism Caffeine and Resistance Training

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) lowe 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 and Resistance training

Dietary Supplement

Acute caffeine intake (3 mg/kg) prior each resistance training session of a 8 weeks training program.

Placebo and Resistance training

Dietary Supplement

Acute placebo intake (3 mg/kg of maltodextrin) prior each resistance training session of a 8 weeks training program.

Primary outcomes

  1. Mean velocity at different %1RM

    Time frame: Through study completion, an average of 12 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 12 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 12 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 12 weeks

    Measuring during bench press and back squat exercises.

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

    Time frame: Through study completion, an average of 12 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 12 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 12 weeks

    In bench press and back squat exercise

  8. Resting Metabolic Rate (RMR)

    Time frame: Through study completion, an average of 12 weeks

    Kcal at rest using a metabolic chart.

  9. Maximal Fat Oxidation Rate (MFO)

    Time frame: Through study completion, an average of 12 weeks

    g/min (MFO) using a metabolic chart.

Secondary outcomes

  1. Fat-free mass

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

    Using electrical bioimpedance and untrasound in the quadriceps muscle

  2. Fat mass

    Time frame: Through study completion, an average of 12 weeks

    Using electrical bioimpedance (kg and % of body mass)

  3. Physical activity (METs-min/wk)

    Time frame: Through study completion, an average of 12 weeks

    Using IPAQ

  4. Dietary (g/kg of macronutrients)

    Time frame: Through study completion, an average of 12 weeks

    Using a 24-total recall

  5. Mood state

    Time frame: Through study completion, an average of 12 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.

  6. Adverse effects

    Time frame: Through study completion, an average of 12 weeks

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

Sponsors and collaborators

Lead sponsor

University of Alcala

Other

Registry information

Official study title

Influence of CYP1A2 on the Prolonged Effect of Caffeine Intake on Resistance Training

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
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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