Placebo Effect on Cycling Performance: Laboratory Crossover Study
15 september 2026 bijgewerkt door: Poznan University of Physical Education
The Impact of Expectations on Physical Performance and Psychophysiological Potential: a Randomized, Double-blind, Placebo-controlled Crossover Study on the Placebo Effect in the Context of Caffeine Supplementation
This study aims to determine the impact of the placebo (PLA) effect on physical and cognitive performance in a controlled laboratory setting.
The study investigates how expectations and beliefs about substance intake (caffeine vs. placebo) interact with actual consumption to influence performance and physiological stress markers.
Healthy adults (n = 80) will participate in four testing sessions using a randomized, double-blind, placebo-controlled crossover design.
Physiological stress markers (cortisol and alpha-amylase), heart rate, and performance metrics will be monitored during a standardized cycling exercise protocol.
This phase provides the dense mechanistic data required to refine a mathematical model of the placebo effect, offering insights into how individual personality traits and cognitive anchoring influence psychophysiological potential.
Studie Overzicht
Toestand
Nog niet aan het werven
Interventie / Behandeling
Gedetailleerde beschrijving
This study employs a randomized, double-blind, placebo-controlled crossover design to conduct a multifactorial analysis of psychophysiological and biomechanical dynamics.
Participants (n = 80, aged 20-35 years) will complete four experimental sessions separated by 7-day washout periods, involving caffeine (6 mg/kg) or placebo administration.
The laboratory protocol (160 minutes) integrates multiple modalities: (1) cognitive testing (Reaction Time Test and Flanker Test), (2) postural control assessment using the BTrackS Balance Plate, and (3) a standardized cycle ergometer exercise protocol consisting of 15 minutes at the anaerobic threshold followed by a 5-minute self-paced maximal effort trial.
Belief manipulation (immediate vs. retrospective reporting) and cognitive anchoring (feedback conditions) are implemented to isolate expectancy-driven effects.
Continuous metabolic and cardiorespiratory data collected using the Cosmed K5 system will be synchronized with blood biomarkers (lactate, glucose, caffeine, and paraxanthine) and salivary biomarkers (cortisol, testosterone, and alpha-amylase).
Advanced statistical methods, including Functional Data Analysis (FDA) and machine learning, will be used to integrate physiological trajectories with behavioral predictors.
Studietype
Ingrijpend
Inschrijving (Geschat)
80
Fase
- Niet toepasbaar
Contacten en locaties
In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.
Studiecontact
- Naam: Jakub Malik, PhD
- Telefoonnummer: +48739975701
- E-mail: malik@awf.poznan.pl
Studie Locaties
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Wielkopolska
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Poznan, Wielkopolska, Polen
- Poznań University of Physical Education
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Contact:
- Jakub Malik, PhD
- Telefoonnummer: +48739975701
- E-mail: malik@awf.poznan.pl
-
-
Deelname Criteria
Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.
Geschiktheidscriteria
Leeftijden die in aanmerking komen voor studie
- Volwassen
Accepteert gezonde vrijwilligers
Ja
Beschrijving
Inclusion Criteria:
- Age between 20 and 35 years,
- Healthy adults,
- Regular physical activity, but not professional athletes,
- Normal or corrected-to-normal vision,
- Habitual caffeine consumption.
Exclusion Criteria:
- History of neurological, psychiatric, cardiovascular, or metabolic disorders,
- Current use of medication or supplements affecting the central nervous system,
- Musculoskeletal injuries that would impair physical performance,
- No habitual caffeine consumption or severe negative side effects of caffeine,
- Diagnosed sleep disorders or chronic fatigue,
- Diagnosed major depressive disorder or other severe psychiatric conditions,
- Presence of any menstrual disorders,
- Inability to attend all experimental study visits.
Studie plan
Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.
Hoe is de studie opgezet?
Ontwerpdetails
- Primair doel: Fundamentele wetenschap
- Toewijzing: Gerandomiseerd
- Interventioneel model: Crossover-opdracht
- Masker: Verviervoudigen
Wapens en interventies
Deelnemersgroep / Arm |
Interventie / Behandeling |
|---|---|
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Experimenteel: Sequence AABB
Participants follow the sequence: Caffeine, Caffeine, Placebo, Placebo, with a 7-day washout period between sessions.
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Anhydrous caffeine administered in an encapsulated form at a dosage of 6 mg per kilogram of body mass, 60 minutes before the exercise protocol.
Corn starch administered in an identical encapsulated form as the active caffeine, 60 minutes prior to the laboratory exercise protocol.
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Experimenteel: Sequence BBAA
Participants follow the sequence: Placebo, Placebo, Caffeine, Caffeine, with a 7-day washout period between sessions.
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Anhydrous caffeine administered in an encapsulated form at a dosage of 6 mg per kilogram of body mass, 60 minutes before the exercise protocol.
Corn starch administered in an identical encapsulated form as the active caffeine, 60 minutes prior to the laboratory exercise protocol.
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Experimenteel: Sequence ABAB
Participants follow the sequence: Caffeine, Placebo, Caffeine, Placebo, with a 7-day washout period between sessions.
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Anhydrous caffeine administered in an encapsulated form at a dosage of 6 mg per kilogram of body mass, 60 minutes before the exercise protocol.
Corn starch administered in an identical encapsulated form as the active caffeine, 60 minutes prior to the laboratory exercise protocol.
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Experimenteel: Sequence BABA
Participants follow the sequence: Placebo, Caffeine, Placebo, Caffeine, with a 7-day washout period between sessions.
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Anhydrous caffeine administered in an encapsulated form at a dosage of 6 mg per kilogram of body mass, 60 minutes before the exercise protocol.
Corn starch administered in an identical encapsulated form as the active caffeine, 60 minutes prior to the laboratory exercise protocol.
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Wat meet het onderzoek?
Primaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
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Physical Work Capacity (total work in J)
Tijdsspanne: Measured during each laboratory exercise protocol (approximately 85-120 minutes).
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Total physical work performed, expressed in Joules (J), during the standardized laboratory exercise protocol, including both the Anaerobic Threshold phase and the Self-paced Maximal Time-trial.
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Measured during each laboratory exercise protocol (approximately 85-120 minutes).
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Postural Control (mm)
Tijdsspanne: Measured continuously during the exercise protocol and at T1 (minute 2), T2 (minute 55), and T3 (minute 125).
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Center of Pressure excursions measured using the BTrackS Balance Plate and expressed in millimeters (mm).
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Measured continuously during the exercise protocol and at T1 (minute 2), T2 (minute 55), and T3 (minute 125).
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Explosive power variables (mm)
Tijdsspanne: Continuous recording throughout the exercise protocol and discrete assessments at T1 (2 minute of protocol), T2 (55 minute of protocol), and T3 (125 minute of protocol).
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Explosive lower-limb power expressed in millimeters (mm) - Countermovement Jump - height.
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Continuous recording throughout the exercise protocol and discrete assessments at T1 (2 minute of protocol), T2 (55 minute of protocol), and T3 (125 minute of protocol).
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Psychomotor Vigilance Test Reaction Time (ms)
Tijdsspanne: Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Reaction time during the Psychomotor Vigilance Test expressed in milliseconds (ms).
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Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Flanker Test Reaction Time (ms)
Tijdsspanne: Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Reaction time during the Flanker Test expressed in milliseconds (ms).
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Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Secundaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
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Exercise Heart Rate (bpm)
Tijdsspanne: Measured continuously during each laboratory exercise protocol (approximately 85-120 minutes).
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Heart rate expressed in beats per minute (bpm) recorded continuously throughout the standardized laboratory exercise protocol.
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Measured continuously during each laboratory exercise protocol (approximately 85-120 minutes).
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Exercise Heart Rate Variability (ms)
Tijdsspanne: Measured continuously during each laboratory exercise protocol (approximately 85-120 minutes).
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Heart rate variability expressed in milliseconds (ms) and recorded continuously throughout the standardized laboratory exercise protocol to assess autonomic regulation.
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Measured continuously during each laboratory exercise protocol (approximately 85-120 minutes).
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Simple Reaction Time (ms)
Tijdsspanne: Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Reaction time during the Simple Reaction Time test expressed in milliseconds (ms).
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Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Heart Rate Recovery (bpm)
Tijdsspanne: Measured continuously during the first 5 minutes immediately following exercise cessation.
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Heart rate recorded during the post-exercise recovery period, expressed in beats per minute (bpm).
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Measured continuously during the first 5 minutes immediately following exercise cessation.
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Rating of Perceived Exertion (Borg Scale, points)
Tijdsspanne: Before and immediately after warm-up, immediately after the Anaerobic Threshold phase, immediately after the Self-paced Maximal Time-trial, and immediately after cooldown during each laboratory study visit.
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Perceived exertion will be assessed using the Borg Rating of Perceived Exertion Scale and reported in points (6-20).
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Before and immediately after warm-up, immediately after the Anaerobic Threshold phase, immediately after the Self-paced Maximal Time-trial, and immediately after cooldown during each laboratory study visit.
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Personality Traits (NEO-FFI, points)
Tijdsspanne: Measured at baseline (first study visit).
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Personality traits will be assessed using the NEO Five-Factor Inventory (NEO-FFI).
The questionnaire provides scores for five personality domains: Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness.
Results will be reported as domain scores in points.
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Measured at baseline (first study visit).
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Mood State (POMS/BRUMS) (points)
Tijdsspanne: Measured during each laboratory study visit.
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Mood state assessed using the Profile of Mood States (POMS/BRUMS), expressed in points.
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Measured during each laboratory study visit.
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Caffeine Expectancy (Caff-EQ-Brief) (points)
Tijdsspanne: Measured 30 minutes post-ingestion.
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Caffeine expectancy assessed using the Caffeine Expectancy Questionnaire-Brief (Caff-EQ-Brief), expressed in points.
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Measured 30 minutes post-ingestion.
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Urine pH
Tijdsspanne: Measured once prior to the start of each laboratory study visit.
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Urine pH measured using a urine strip analyzer.
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Measured once prior to the start of each laboratory study visit.
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White blood cells count and differential (count/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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White blood cells count and differential (%)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (red blood cells, RBC) (count/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (hemoglobin concentration, HGB) (mmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (hematocrit, HCT) (L/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (mean corpuscular volume, MCV; mean platelet volume, MPV) (fL)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (mean corpuscular hemoglobin mass, MCH) (fmol)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (mean corpuscular hemoglobin concentration, MCHC) (mmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (platelet count, PLT) (count/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (platelet hematocrit, PCT) (cL/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (platelet distribution width, PDW; platelet large cell ratio, PLCR; red blood cells distribution width - coefficient of variation, RDW-C) (%)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Hematological indices (red blood cells distribution width - standard deviation, RDW-S) (fL)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the hematological parameter will be performed from fingertip capillary blood collected before supplementation (baseline), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Urea Concentration (mmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Urea concentration measured from fingertip capillary blood and expressed in mmol/L.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Glucose Concentration (mg/dL)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Glucose concentration measured from fingertip capillary blood and expressed in mg/dL.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Creatinine concentration (μmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Creatinine concentration measured from fingertip capillary blood and expressed in µmol/L.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Muscle damage markers (activity of alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase) (U/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of the muscle damage markers (activity of alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase) (U/L) will be performed from fingertip capillary blood.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Lactate concentration (mmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Blood lactate concentration measured from fingertip capillary blood and expressed in mmol/L.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Electrolites' concentration (Ca, Na, K, Cl) (mmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of electrolites' concentration (Ca, Na, K, Cl) (mmol/L) will be performed from fingertip capillary blood.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Blood pH
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of gasometry markers (blood pH) will be performed from fingertip capillary blood.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Partial Pressure of Carbon Dioxide and Oxygen (pCO2, pO2) (mmHg)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of gasometry markers (pCO2, pO2) (mmHg) will be performed from fingertip capillary blood.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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CAF and PAX concentrations (µmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Assessment of caffeine and paraxanthine concentrations (µmol/L) will be performed from fingertip capillary blood.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before exercise, and 3 minutes post-exercise.
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Static weight distribution (mm)
Tijdsspanne: Measured at the start of each study visit.
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Static weight distribution expressed in millimeters of Center of Pressure symmetry.
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Measured at the start of each study visit.
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Analysis of body composition (fat-free mass, fat mass) (kg)
Tijdsspanne: Measured at the start of each study visit.
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Assessment of body composition (fat-free mass, fat mass) (kg) will be carried out at the start of each study visit.
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Measured at the start of each study visit.
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Analysis of body composition (total body water) (L)
Tijdsspanne: Measured at the start of each study visit.
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Assessment of body composition (total body water) (L) will be carried out at the start of each study visit.
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Measured at the start of each study visit.
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Analysis of body composition (total body water) (%)
Tijdsspanne: Measured at the start of each study visit.
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Assessment of body composition (total body water) (%) will be carried out at the start of each study visit.
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Measured at the start of each study visit.
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Autonomic Response during Cognitive Performance (bpm)
Tijdsspanne: Measured at three time points: T1 (pre-ingestion; 2 minute of protocol), T2 (post-ingestion/pre-exercise; 55 minute of protocol), and T3 (post-exercise; 125 minute of protocol).
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Heart rate and heart rate variability recording during cognitive testing blocks, expressed in beats per minute (bpm).
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Measured at three time points: T1 (pre-ingestion; 2 minute of protocol), T2 (post-ingestion/pre-exercise; 55 minute of protocol), and T3 (post-exercise; 125 minute of protocol).
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Anthropometric Indices (kg)
Tijdsspanne: Measured at the start of each study visit.
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Body mass in kilograms will be measured at the start of each study visit.
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Measured at the start of each study visit.
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Anthropometric Indices (metres)
Tijdsspanne: Measured at the start of each study visit.
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Height in metres will be measured at the start of each study visit.
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Measured at the start of each study visit.
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Explosive power variables (ms)
Tijdsspanne: Continuous recording throughout the exercise protocol and discrete assessments at T1 (2 minute of protocol), T2 (55 minute of protocol), and T3 (125 minute of protocol).
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Explosive lower-limb power variables expressed in milliseconds (ms) - Countermovement Jump - contact time and flight time.
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Continuous recording throughout the exercise protocol and discrete assessments at T1 (2 minute of protocol), T2 (55 minute of protocol), and T3 (125 minute of protocol).
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Explosive power variables (W)
Tijdsspanne: Continuous recording throughout the exercise protocol and discrete assessments at T1 (2 minute of protocol), T2 (55 minute of protocol), and T3 (125 minute of protocol).
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Explosive lower-limb power expressed in Watts (W) - Countermovement Jump - power.
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Continuous recording throughout the exercise protocol and discrete assessments at T1 (2 minute of protocol), T2 (55 minute of protocol), and T3 (125 minute of protocol).
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Hydration Status (g/mL)
Tijdsspanne: Once prior to the start of each laboratory study visit.
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Assessment of urine specific gravity (g/mL) using a urine strip analyzer.
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Once prior to the start of each laboratory study visit.
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Flanker Test Accuracy (%)
Tijdsspanne: Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Accuracy during the Flanker Test expressed as the percentage of correct responses.
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Measured at T1 (pre-ingestion, minute 2 of the protocol), T2 (post-ingestion/pre-exercise, minute 55 of the protocol), and T3 (post-exercise, minute 125 of the protocol).
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Heart Rate Variability Recovery (ms)
Tijdsspanne: Measured continuously during the first 5 minutes immediately following exercise cessation.
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Heart rate variability expressed in milliseconds (ms) during the post-exercise recovery period.
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Measured continuously during the first 5 minutes immediately following exercise cessation.
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Caffeine Expectancy Questionnaire Score (points)
Tijdsspanne: Measured 30 minutes post-ingestion.
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Caffeine expectancy assessed using the Caffeine Expectancy Questionnaire and expressed in points.
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Measured 30 minutes post-ingestion.
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Suggestibility (SSS) (points)
Tijdsspanne: Measured during the last study visit.
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General suggestibility assessed using the Short Suggestibility Scale (SSS), expressed in points.
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Measured during the last study visit.
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Intrinsic Motivation (IMI) (points)
Tijdsspanne: Measured after each test block during every laboratory study visit.
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Task-specific intrinsic motivation assessed using the Intrinsic Motivation Inventory (IMI), expressed in points.
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Measured after each test block during every laboratory study visit.
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Sport Motivation (SMS) (points)
Tijdsspanne: Measured during the first study visit.
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Sport motivation assessed using the Sport Motivation Scale (SMS), expressed in points.
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Measured during the first study visit.
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Sleep Quality (LSEQ) (points)
Tijdsspanne: Measured once during each laboratory study visit.
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Subjective sleep quality assessed using the Leeds Sleep Evaluation Questionnaire (LSEQ), expressed in points.
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Measured once during each laboratory study visit.
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Salivary Cortisol Concentration (nmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before warm-up (60 minutes post-ingestion), 3 minutes post-exercise, and 10 minutes post-exercise.
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Salivary cortisol concentration expressed in nmol/L.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before warm-up (60 minutes post-ingestion), 3 minutes post-exercise, and 10 minutes post-exercise.
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Salivary Testosterone Concentration (pmol/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before warm-up (60 minutes post-ingestion), 3 minutes post-exercise, and 10 minutes post-exercise.
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Salivary testosterone concentration expressed in pmol/L.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before warm-up (60 minutes post-ingestion), 3 minutes post-exercise, and 10 minutes post-exercise.
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Salivary Alpha-amylase Activity (U/L)
Tijdsspanne: Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before warm-up (60 minutes post-ingestion), 3 minutes post-exercise, and 10 minutes post-exercise.
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Salivary alpha-amylase activity expressed in U/L.
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Measured at baseline (pre-supplementation), 30 minutes post-ingestion, before warm-up (60 minutes post-ingestion), 3 minutes post-exercise, and 10 minutes post-exercise.
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Medewerkers en onderzoekers
Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.
Onderzoekers
- Hoofdonderzoeker: Jakub Malik, PhD, Poznan University of Physical Education, Department of Sports Psychology
Studie record data
Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.
Bestudeer belangrijke data
Studie start (Geschat)
1 januari 2027
Primaire voltooiing (Geschat)
31 maart 2028
Studie voltooiing (Geschat)
31 maart 2029
Studieregistratiedata
Eerst ingediend
21 juli 2026
Eerst ingediend dat voldeed aan de QC-criteria
31 juli 2026
Eerst geplaatst (Werkelijk)
5 augustus 2026
Updates van studierecords
Laatste update geplaatst (Werkelijk)
18 september 2026
Laatste update ingediend die voldeed aan QC-criteria
15 september 2026
Laatst geverifieerd
1 juli 2026
Meer informatie
Termen gerelateerd aan deze studie
Trefwoorden
Aanvullende relevante MeSH-voorwaarden
Andere studie-ID-nummers
- 152-2-26
- 2025/57/N/NZ4/04470 (Ander subsidie-/financieringsnummer: National Science Centre)
Plan Individuele Deelnemersgegevens (IPD)
Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?
JA
Beschrijving IPD-plan
The study protocol will be published as an open-access article.
Upon completion of the study, de-identified individual participant data (IPD) and relevant analytic code will be deposited in an open-access repository such as Zenodo or OSF, following the FAIR principles.
IPD-tijdsbestek voor delen
The study protocol will be available upon its publication.
The IPD and analytic code will be available starting from the date of the primary study results publication and will remain accessible for at least 5 years.
IPD-toegangscriteria voor delen
The study protocol will be published as an open-access article.
Upon completion of the study, de-identified individual participant data (IPD) and relevant analytic code will be deposited in an open-access repository such as Zenodo or OSF, in accordance with FAIR principles.
IPD delen Ondersteunend informatietype
- LEERPROTOCOOL
Informatie over medicijnen en apparaten, studiedocumenten
Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel
Nee
Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct
Nee
Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .