Placebo Effect in Field-Based Physical Performance

July 31, 2026 updated by: 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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

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

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 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).
Drug: 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.
Active Comparator: Placebo Group
Participants ingest a single dose of placebo (corn starch) in an identical capsule prior to a field-based exercise protocol.
Other: Placebo (Starch capsule)
Corn starch administered in an identical encapsulated form as the active caffeine, 30-60 minutes before the exercise protocol.
Sham Comparator: Control Group
Participants perform the same field-based exercise protocol without ingesting any capsule or active substance.
Other: Sham (No Treatment)
Participants perform the same exercise protocols without any capsule or substance administration.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Physical Performance Capacity (total distance in running, metres)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Exercise Heart Rate (bpm)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: Measured at the start of the protocol.
Body mass expressed in kilograms.
Measured at the start of the protocol.
Anthropometric Indices (m)
Time Frame: 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)
Time Frame: 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) (%)
Time Frame: 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)
Time Frame: 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) (%)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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)
Time Frame: 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 (%)
Time Frame: 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)
Time Frame: 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.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Poznan University of Physical Education

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jakub Malik, PhD, Poznan University of Physical Education, Department of Sports Psychology

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 31, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 21, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 31, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 3, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 3, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 31, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 152-1-26
  • 2025/57/N/NZ4/04470 (Other Grant/Funding Number: National Science Centre)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

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.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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