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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
26
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.
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.
Department of Sports Dietetics, Poznan University of Physical Education
Poznan, Wielkopolska, Poland
Changes in discipline-specific exercise capacity after caffeine supplementation and placebo treatment
Assessment of the discipline-specific exercise capacity tests carried out at baseline, and after CAF and PLA supplementation
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in caffeine and paraxanthine concencentrations in serum and saliva before and after caffeine supplementation and placebo treatment
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.
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in reaction and motor time (Vienna Test System) after caffeine supplementation and placebo treatment
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
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in postural stability indices (COP velocity, Vcop) (posturographic platform AccuGaitTM) (after caffeine supplementation and placebo treatment
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
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in postural stability indices (area 95 percentile, Area95) (posturographic platform AccuGaitTM) after caffeine supplementation and placebo treatment
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
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Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in sports training / competition activities after discipline-specific exercise tests
Assessment of the sports training / competition activities after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in rate of perceived exertion after discipline-specific exercise tests
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
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in heart rate during discipline-specific exercise tests
Assessment of the Heart Rate during and after discipline-specific exercise tests carried out at baseline, and after CAF and PLA supplementation
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Analysis of psychological state before and after caffeine supplementation and placebo
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
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Analysis of macronutrients in diets before and after caffeine supplementation and placebo treatment
Assessment of the macronutrients in diets (g) was carried out before the execution of exercise protocols on each research visit
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Analysis of body composition (fat-free mass, fat mass)
Assessment of body composition (fat-free mass, fat mass) (kg) was carried out before the execution of exercise protocols on each research visit
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Analysis of body composition (total body water)
Assessment of body composition (total body water) (%) was carried out before the execution of exercise protocols on each research visit
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Changes in lactate and pyruvate concentrations in capillary blood before and after caffeine supplementation and placebo treatment
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
Time frame: Baseline and during 1 day of acute CAF and PLA supplementation
Analysis of gene polymorphisms
Assessment of the chosen gene polymorphisms in saliva carried out at baseline
Time frame: Baseline