Placebo Effects Investigated by Different Experimental Designs

NCT04317157 | Unknown

• 1 other identifier: USP-NorthumbriaUNI
• Study Type: interventional
• Target: 18
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to investigate the neurophysiological mechanisms of placebo perceived as caffeine during a motor task. Central and peripheral measures (i.e. electroencephalography and electromyography) will be assessed.

Conditions

Caffeine; Placebo; Baseline

Keywords

Randomized clinical trial; Expectancy; Placebo; Caffeine

Outcome Measures

Primary Outcomes (7)

• Torque change

  Knee extension torque (N∙m) will be recorded during a maximal voluntary contraction through a load cell (EMG System ®, São José dos Campos, Brazil) coupled to a custom-built knee extension chair. Participants will have their torso individually adjusted on a backrest, in a comfortable position, fixed with straps to avoid body movement.

  30 minutes before the intervention and up to 60 minutes after the intervention

• Rate of force development change

  Rate of force development (N∙m/s) will be recorded during a maximal voluntary contraction through a load cell (EMG System ®, São José dos Campos, Brazil) coupled to a custom-built knee extension chair. Participants will have their torso individually adjusted on a backrest, in a comfortable position, fixed with straps to avoid body movement.

  30 minutes before the intervention and up to 60 minutes after the intervention

• Muscle activity change

  Vastus lateralis and vastus medialis muscles electromyography (EMG; (mV) will be assessed throughout both the exercises (maximal voluntary contraction and submaximal isometric voluntary contraction) according to standard recommendation.

  Throughout the exercises performed 30 minutes before the intervention and up to 60 minutes after the intervention

• H-reflex change

  H-reflex (mV) will be recorded at 10 s intervals through wireless electrodes placed over the vastus lateralis and vastus medialis muscles at rest, being considered as the peak-to-peak amplitude.

  30 minutes before the intervention and up to 60 minutes after the intervention

• M-wave change

  M- and (mV) will be recorded at 10 s intervals through wireless electrodes placed over the vastus lateralis and vastus medialis muscles at rest, being considered as the peak-to-peak amplitude.

  30 minutes before the intervention and up to 60 minutes after the intervention

• V-wave change

  V-wave (mV) and V-wave/Mmax (a.u.) will be recorded at 10 s intervals through wireless electrodes placed over the vastus lateralis and vastus medialis muscles at rest, being considered as the peak-to-peak amplitude.

  30 minutes before the intervention and up to 60 minutes after the intervention

• Motor related cortical potential change

  Will be recorded at Fz, Cz, Pz, C1 and C2 positions (µV) by using an electroencephalogram (EEG); the EEG recorded during the EMG burst (from 2 s before up to 4 s after the EMG onset) will be used to calculate the EEG amplitude (μv) in 4 windows within the muscle contraction such as; readiness potential (-1,5 to 0 s), muscle contraction 1 (0 to 1 s), muscle contraction 2 (1 to 2 s) and recovery (3 to 4 s).

  Throghout the isometric contraction 30 minutes before the intervention and up to 60 minutes after the intervention

Secondary Outcomes (1)

• Ratings o perceived exertion change

  Throughout the isometric contraction 30 minutes before the intervention and up to 60 minutes after the intervention

Study Arms (6)

Caffeine Clinical Trial

EXPERIMENTAL

Participants will ingest 6 mg.kg-1 of caffeine \~45 minutes before the trial, in a double-blinded, randomized clinical trial fashion.

Other: Placebo

Placebo Clinical Trial

PLACEBO COMPARATOR

Participants will ingest placebo \~45 minutes before the trial, in a double-blinded, randomized clinical trial fashion.

Other: Placebo

Placebo-deceived Caffeine

EXPERIMENTAL

Participants will be lead to believe that they are ingesting 6 mg.kg-1 of caffeine \~45 minutes before the trial.

Other: Placebo

Placebo-deceived Placebo

PLACEBO COMPARATOR

Participants will be informed they are ingesting placebo \~45 minutes before the trial.

Other: Placebo

Control-Caffeine

ACTIVE COMPARATOR

Participants will be informed they are ingesting 6 mg.kg-1 of caffeine \~45 minutes before the trial.

Dietary Supplement: Caffeine

Control

NO INTERVENTION

Participants will perform a baseline trial with no intervention.

Interventions

Caffeine DIETARY_SUPPLEMENT

Specific dosage of caffeine for each participant (6 mg.kg-1).

Control-Caffeine

Placebo OTHER

Placebo pill.

Caffeine Clinical Trial; Placebo Clinical Trial; Placebo-deceived Caffeine; Placebo-deceived Placebo

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy subjects
• Must be able to swallow pills
• Must be able to perform isometric knee extension

You may not qualify if:

• Subjects with motor impairments

Sponsors & Collaborators

• University of Sao Paulo: lead
• Newcastle University: collaborator

Study Sites (1)

School of Arts, Sciences and Humanities - University of São Paulo

São Paulo, 03828-000, Brazil

Location

Related Publications (2)

• Beedie C, Benedetti F, Barbiani D, Camerone E, Cohen E, Coleman D, Davis A, Elsworth-Edelsten C, Flowers E, Foad A, Harvey S, Hettinga F, Hurst P, Lane A, Lindheimer J, Raglin J, Roelands B, Schiphof-Godart L, Szabo A. Consensus statement on placebo effects in sports and exercise: The need for conceptual clarity, methodological rigour, and the elucidation of neurobiological mechanisms. Eur J Sport Sci. 2018 Nov;18(10):1383-1389. doi: 10.1080/17461391.2018.1496144. Epub 2018 Aug 16.

  PMID: 30114971 BACKGROUND

• Pires FO, Dos Anjos CAS, Covolan RJM, Fontes EB, Noakes TD, St Clair Gibson A, Magalhaes FH, Ugrinowitsch C. Caffeine and Placebo Improved Maximal Exercise Performance Despite Unchanged Motor Cortex Activation and Greater Prefrontal Cortex Deoxygenation. Front Physiol. 2018 Aug 17;9:1144. doi: 10.3389/fphys.2018.01144. eCollection 2018.

  PMID: 30246799 RESULT

MeSH Terms

Interventions

Caffeine

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Flavio O Pires, Phd

  School of Arts, Sciences and Humanities - University of São Paulo

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Flavio O Pires, PhD

CONTACT

+55+11+995335777; piresfo@usp.br

Cayque Brietzke, Msc

CONTACT

+55+11+997974897; cayquebbarreto@alumni.usp.br

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Participants and the investigator that will be in touch with participants, will be blinded regarding the interventions.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head of Physical Activity Sciences Program

Model Details: There are five experimental conditions in a crossover design. Participants will receive placebos in four of these trials and caffeine in the other one.

Study Record Dates

• First Submitted: March 9, 2020
• First Posted: March 23, 2020
• Study Start: January 1, 2022
• Primary Completion: July 1, 2022
• Study Completion: August 1, 2022
• Last Updated: June 15, 2021

Record last verified: 2021-06

Data Sharing

• IPD Sharing: Will share

Locations

BR (1)