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Completed

NCT Number: NCT03822663

The Influence of Caffeine Supplementation on Specific Performance and Training Activities

The purpose of this study is to verify the effect of acute caffeine (CAF) and placebo (PLA) supplementation on physical capacity and discipline-specific exercise performance in athletes, in a randomised, double-blind, placebo-controlled crossover trial.

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Key information

Conditions

Supplementation Sports

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Department of Sports Dietetics, Poznan University of Physical Education

Poznan, Wielkopolska, 61-871, Poland

About this study

Caffeine (CAF) is often proposed as an ergogenic agent, especially during high-intensity efforts. CAF supplementation may reduce effort-induced multi-faceted symptoms of fatigue and can improve psychomotor functions (like agility or decision-making processes), which is required during the intermittent high-intensity efforts in combat sports and speed-strength disciplines. Moreover, it is suggested that CAF treatment is associated with increased glycolytic activity during simulated or real training/competition bouts, which results in performance and physical capacity improvement.

However, there are hardly any data on the individual CAF-induced and dose-dependent changes in physical capacity and discipline-specific performance in combat sports and speed-strength disciplines. Therefore, the study aims to examine the effect of acute, different-dose CAF ingestion on physical capacity and discipline-specific performance in combat sports and speed-strength athletes, in a randomized, double-blind, placebo-controlled crossover trial.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • written consent to participate,
  • a current medical clearance to practice sports,
  • training experience: at least 2 years,
  • minimum of 4 workout sessions (in the discipline covered by the study) a week.

Exclusion criteria

  • current injury,
  • any health-related contraindication,
  • declared general feeling of being unwell,
  • unwilling to follow the study protocol.

Treatment and study plan

Caffeine supplementation

Dietary Supplement

The experimental procedure for each athlete includes an acute CAF supplementation in a different-dose crossover regimen in order to assess whether the dose affects the actual physical capacity and discipline-specific exercise performance (doses: 3.0-, 6.0- and 9.0 mg/kg of body mass, respectively). CAF (pure pharmaceutical caffeine) will be administered in the dissolved form. On testing days, the supplements will be taken 70 min before physical and exercise capacity test session. Between the CAF and PLA or a PLA and CAF treatments, a minimum 7-day washout period will be introduced.

Placebo treatment

Dietary Supplement

The experimental procedure for each athlete will include PLA supplementation. Placebo will be administered in the dissolved form. On testing days, the PLA will be taken 70 min before physical and exercise capacity test session. Between the PLA and CAF or a CAF and PLA treatments, a minimum 7-day washout period will be introduced.

Primary outcomes

  1. Changes in discipline-specific exercise capacity after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the discipline-specific exercise capacity tests carried out at baseline, and after CAF and PLA supplementation

  2. Changes in caffeine and paraxanthine concencentrations in serum and saliva before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the caffeine and paraxanthine concencentrations (μg/mL), and paraxanthine/caffeine ratio in serum and saliva before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation. Additionally CYP1A2 enzyme activity was assessed by the determination of the mean time-corrected PRX/CAF RATIO in saliva.

  3. Changes in reaction and motor time (Vienna Test System) after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the reaction and motor time (Vienna Test System) (ms) before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  4. Changes in postural stability indices (COP velocity, Vcop) (posturographic platform AccuGaitTM) (after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the postural stability indices (COP velocity, Vcop) (posturographic platform AccuGaitTM) (cm/s) before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  5. Changes in postural stability indices (area 95 percentile, Area95) (posturographic platform AccuGaitTM) after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the postural stability indices (area 95 percentile, Area95) (posturographic platform AccuGaitTM) (cm2) before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

Secondary outcomes

  1. Changes in sports training / competition activities after discipline-specific exercise tests

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the sports training / competition activities after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  2. Changes in rate of perceived exertion after discipline-specific exercise tests

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the Borg Rating of Perceived Exertion (RPE) scale after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  3. Changes in heart rate during discipline-specific exercise tests

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the Heart Rate during and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  4. Analysis of psychological state before and after caffeine supplementation and placebo

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of psychological state by chosen questionnaires was carried out before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  5. Analysis of macronutrients in diets before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the macronutrients in diets (g) was carried out before the execution of exercise protocols on each research visit

  6. Analysis of body composition (fat-free mass, fat mass)

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of body composition (fat-free mass, fat mass) (kg) was carried out before the execution of exercise protocols on each research visit

  7. Analysis of body composition (total body water)

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of body composition (total body water) (%) was carried out before the execution of exercise protocols on each research visit

  8. Changes in lactate and pyruvate concentrations in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the lactate and pyruvate concentration (mmol/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  9. Analysis of gene polymorphisms

    Time frame: Baseline

    Assessment of the chosen gene polymorphisms in saliva carried out at baseline

Other outcomes

  1. Changes in white blood cells and hematological indices (red blood cells, RBC) count in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the leukocytes (neutrophils, monocytes, lymphocytes, neutrophils:lymphocytes ratio) and the hematological indices (red blood cells, RBC)(count/L) count in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  2. Changes in hematological indices (hemoglobin concentration, HGB) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (hemoglobin concentration, HGB) (mmol/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  3. Changes in hematological indices (hematocrit, HCT) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (hematocrit, HCT) (L/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  4. Changes in hematological indices (mean corpuscular volume, MCV; mean platelet volume, MPV) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (mean corpuscular volume, MCV; mean platelet volume, MPV) (fL) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  5. Changes in hematological indices (mean corpuscular hemoglobin mass, MCH) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (mean corpuscular hemoglobin mass, MCH) (fmol) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  6. Changes in hematological indices (mean corpuscular hemoglobin concentration, MCHC) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (mean corpuscular hemoglobin concentration, MCHC) (mmol/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  7. Changes in hematological indices (platelet count, PLT) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (platelet count, PLT) (count x 109/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  8. Changes in hematological indices (platelet hematocrit, PCT) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (platelet hematocrit, PCT) (cL/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  9. Changes in hematological indices (platelet distribution width, PDW; platelet large cell ratio, PLCR; red blood cells distribution width - coefficient of variation, RDW-C) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (platelet distribution width, PDW; platelet large cell ratio, PLCR; red blood cells distribution width - coefficient of variation, RDW-C) (%) in in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  10. Changes in hematological indices (red blood cells distribution width - standard deviation, RDW-S) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the hematological indices (red blood cells distribution width - standard deviation, RDW-S) (fL) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  11. Changes in nutritional status indices (concentration of urea and magnesium) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the nutritional status indices (concentration of urea and magnesium) (mmol/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  12. Changes in nutritional status indices (concentration of glucose, calcium and phosphorans) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the nutritional status indices (concentration of glucose, calcium and phosphorans) (mg/dL) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  13. Changes in muscle damage markers (concentration of creatine) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the muscle damage markers (concentration of creatine) (μmol/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

  14. Changes in muscle damage markers (activity of alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase)) in capillary blood before and after caffeine supplementation and placebo treatment

    Time frame: Baseline and during 1 day of acute CAF and PLA supplementation

    Assessment of the muscle damage markers (activity of alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase) (U/L) in capillary blood before and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation

Sponsors and collaborators

Lead sponsor

Poznan University of Physical Education

Other

Collaborators

  • Poznan University of Life Sciences

Registry information

Official study title

The Influence of Caffeine Supplementation on Discipline-Specific Performance and Training Activities in Combat Sports and Speed-Strength Disciplines

Important dates

Study start
2017
Primary completion
2023
Study completion
2023
First posted
Jan 30, 2019
Registry last updated
Apr 26, 2024

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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