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Placebo Effect in Field-Based Physical Performance

31. juli 2026 opdateret af: Poznan University of Physical Education

Psychophysiological Mechanisms of the Placebo Effect on Physical Performance in Field Settings

This study aims to investigate the placebo (PLA) effect on physical performance across different sports disciplines in real-world, field-based settings. The study investigates how participant expectations and beliefs regarding caffeine (CAF) intake influence physical performance and psychomotor function outside the controlled laboratory environment. Healthy, physically active adults (n = 120) from diverse sports backgrounds will be randomly assigned to receive caffeine, placebo, or no intervention. Participants will perform discipline-specific field exercise tests (e.g., running-based protocols or repeated sprint protocols) while physiological responses are monitored using wearable technology. Physical performance outcomes and psychomotor responses will be analyzed to evaluate the real-world impact of the placebo effect and to distinguish the pharmacological effects of caffeine from those driven by psychological expectations across different athletic settings.

Studieoversigt

Status

Ikke rekrutterer endnu

Betingelser

Intervention / Behandling

Detaljeret beskrivelse

This study employs a cross-sectional design conducted in diverse field settings to investigate the placebo (PLA) effect across different sports disciplines. Participants (n = 120, aged 20-35 years) representing different training profiles (endurance and mixed) will be randomly assigned to one of three parallel groups: Caffeine, Placebo, or Control. Each participant will complete a single experimental session lasting approximately 35 minutes, consisting of: (1) baseline psychomotor assessment using the Simple Reaction Time test, (2) a discipline-specific exercise protocol (e.g., the Cooper test performed on an athletics track or a Repeated Sprint Ability protocol), and (3) post-exercise recovery monitoring. Physiological parameters, including heart rate (HR), heart rate variability (HRV), and respiratory rate (RR), together with postural stability, will be continuously monitored using wearable technology. The study will evaluate how psychological expectations influence physical performance, psychomotor function, and physiological responses during sport-specific exercise, providing evidence for the role of the placebo effect under real-world athletic conditions.

Undersøgelsestype

Interventionel

Tilmelding (Anslået)

120

Fase

  • Ikke anvendelig

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiekontakt

Studiesteder

  • Polen
    • Greater Poland Voivodeship
      • Poznan, Greater Poland Voivodeship, Polen
        • Poznań University of Physical Education
        • Kontakt:

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

  • Voksen

Tager imod sunde frivillige

Ja

Beskrivelse

Inclusion Criteria:

  • Age between 20 and 35 years,
  • Healthy adults,
  • Regular physical activity,
  • 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.

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Grundvidenskab
  • Tildeling: Randomiseret
  • Interventionel model: Parallel tildeling
  • Maskning: Firedobbelt

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Eksperimentel: Caffeine Group
Participants ingest a single dose of caffeine (6mg/kg body mass) prior to a field-based exercise protocol (e.g., Cooper test or Repeated Sprint Ability).
Medicin: Caffeine (6mg/kg)
Anhydrous caffeine administered in an encapsulated form at a dosage of 6mg per kilogram of body mass, 30-60 minutes before the exercise protocol.
Aktiv komparator: Placebo Group
Participants ingest a single dose of placebo (corn starch) in an identical capsule prior to a field-based exercise protocol.
Andet: Placebo (Starch capsule)
Corn starch administered in an identical encapsulated form as the active caffeine, 30-60 minutes before the exercise protocol.
Sham-komparator: Control Group
Participants perform the same field-based exercise protocol without ingesting any capsule or active substance.
Andet: Sham (No Treatment)
Participants perform the same exercise protocols without any capsule or substance administration.

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Physical Performance Capacity (total distance in running, metres)
Tidsramme: Measured during the exercise protocol immediately following administration of the study intervention.
Total physical work capacity measured as the total running distance (metres) completed during the standardized exercise protocol.
Measured during the exercise protocol immediately following administration of the study intervention.
Physical Performance Capacity (total work in Joules for cycling)
Tidsramme: Measured during the exercise protocol immediately following administration of the study intervention.
Total physical work capacity measured as the total mechanical work (Joules) completed during the standardized cycling exercise protocol.
Measured during the exercise protocol immediately following administration of the study intervention.
Physical Performance Capacity (exercise duration until exhaustion, minutes)
Tidsramme: Measured during the exercise protocol immediately following administration of the study intervention.
Total physical work capacity measured as exercise duration until volitional exhaustion during the standardized exercise protocol.
Measured during the exercise protocol immediately following administration of the study intervention.

Sekundære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Exercise Heart Rate (bpm)
Tidsramme: Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Heart rate (beats per minute) recorded continuously throughout the standardized exercise protocol.
Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Cognitive Heart Rate (bpm)
Tidsramme: Measured during cognitive testing immediately before and immediately after the exercise protocol.
Heart rate recorded during standardized cognitive performance tasks.
Measured during cognitive testing immediately before and immediately after the exercise protocol.
Post-Exercise Heart Rate Recovery (bpm)
Tidsramme: Continuously monitored during the first 5 minutes immediately following completion of the exercise protocol.
Heart rate recorded during the post-exercise recovery period.
Continuously monitored during the first 5 minutes immediately following completion of the exercise protocol.
Cognitive Reaction Time (ms)
Tidsramme: Measured immediately before and immediately after the exercise protocol.
Reaction time measured during standardized cognitive tasks (e.g., Psychomotor Vigilance Test, Stroop Test, Flanker Test).
Measured immediately before and immediately after the exercise protocol.
Rating of Perceived Exertion (Borg Scale, points)
Tidsramme: Measured immediately after completion of the exercise protocol.
Perceived exertion assessed using the Borg Rating of Perceived Exertion Scale (6-20).
Measured immediately after completion of the exercise protocol.
Biomechanical Kinematic Profile (cm)
Tidsramme: Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Continuous recording of kinematic parameters derived from wearable sensors, including step length and vertical oscillation.
Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Biomechanical Kinematic Profile (ms)
Tidsramme: Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Continuous recording of stance time derived from wearable sensor data.
Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Biomechanical Kinematic Profile (steps/min)
Tidsramme: Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Continuous recording of cadence derived from wearable sensor data.
Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Anthropometric Indices (kg)
Tidsramme: Measured at the start of the protocol.
Body mass expressed in kilograms.
Measured at the start of the protocol.
Anthropometric Indices (m)
Tidsramme: Measured at the start of the protocol.
Height expressed in metres.
Measured at the start of the protocol.
Body composition (fat-free mass, fat mass) (kg)
Tidsramme: Measured at the start of the protocol.
Assessment of body composition (fat-free mass, fat mass) (kg) will be performed at the start of the protocol.
Measured at the start of the protocol.
Body composition (fat-free mass, fat mass) (%)
Tidsramme: Measured at the start of the protocol.
Assessment of body composition (fat-free mass, fat mass) (%) will be performed at the start of the protocol.
Measured at the start of the protocol.
Body composition (total body water) (L)
Tidsramme: Measured at the start of the protocol.
Assessment of body composition (total body water) (L) will be performed at baseline at the start of the protocol.
Measured at the start of the protocol.
Body composition (total body water) (%)
Tidsramme: Measured at the start of the protocol.
Assessment of body composition (total body water) (%) will be performed at baseline at the start of the protocol.
Measured at the start of the protocol.
Exercise Heart Rate Variability (ms)
Tidsramme: Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Heart rate variability recorded continuously throughout the standardized exercise protocol to assess autonomic regulation.
Continuously monitored during the exercise protocol immediately following administration of the study intervention.
Cognitive Heart Rate Variability (ms)
Tidsramme: Measured during cognitive testing immediately before and immediately after the exercise protocol.
Heart rate variability recorded during standardized cognitive performance tasks.
Measured during cognitive testing immediately before and immediately after the exercise protocol.
Post-Exercise Heart Rate Variability Recovery (ms)
Tidsramme: Continuously monitored during the first 5 minutes immediately following completion of the exercise protocol.
Heart rate variability recorded during the post-exercise recovery period.
Continuously monitored during the first 5 minutes immediately following completion of the exercise protocol.
Cognitive Accuracy (%)
Tidsramme: Measured immediately before and immediately after the exercise protocol.
Accuracy measured during standardized cognitive tasks (e.g., Psychomotor Vigilance Test, Stroop Test, Flanker Test).
Measured immediately before and immediately after the exercise protocol.
Performance Expectancy (points)
Tidsramme: Measured immediately after completion of the exercise protocol.
Measured immediately before the exercise protocol following administration of the study intervention.
Measured immediately after completion of the exercise protocol.

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Sponsor

Poznan University of Physical Education

Efterforskere

  • Ledende efterforsker: Jakub Malik, PhD, Poznan University of Physical Education, Department of Sports Psychology

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Anslået)

1. september 2026

Primær færdiggørelse (Anslået)

31. marts 2028

Studieafslutning (Anslået)

31. marts 2029

Datoer for studieregistrering

Først indsendt

21. juli 2026

Først indsendt, der opfyldte QC-kriterier

31. juli 2026

Først opslået (Faktiske)

3. august 2026

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

3. august 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

31. juli 2026

Sidst verificeret

1. juli 2026

Mere information

Begreber relateret til denne undersøgelse

Nøgleord

Yderligere relevante MeSH-vilkår

Andre undersøgelses-id-numre

  • 152-1-26
  • 2025/57/N/NZ4/04470 (Andet bevillings-/finansieringsnummer: National Science Centre)

Plan for individuelle deltagerdata (IPD)

Planlægger du at dele individuelle deltagerdata (IPD)?

UBESLUTET

IPD-planbeskrivelse

The decision regarding the sharing of individual participant data has not yet been finalized. We are currently evaluating the feasibility, ethical considerations, and data privacy requirements for potential data sharing. A formal plan will be developed and implemented in accordance with institutional policies and regulatory standards upon the completion of the study.

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