Neurophysiological Mechanisms of Placebo and Nocebo Effects in Sports - a Protocol Paper

Summary

This clinical trial aims to investigate the neurophysiological mechanisms of placebo and nocebo effects on sports performance, using Electroencephalography (EEG) and isometric strength testing of the lower extremities.

The primary objective of this trial is to identify temporal mechanisms and cortical regions and networks involved in generating placebo and nocebo effects before (expectation) and at onset of athletic performance (perception).

The trial will include four groups, two of them experimental, one an active control and one natural history, meaning participants in this group will receive no intervention and won't be EEG controlled. Data will be collected on two occasions with baseline data for EEG, expectations and performance as well as key participant characteristics being collected on day one. On day two, in a deceptive process, participants in the two experimental groups will take an inert substance presented as either performance enhancing or inhibiting and subsequently experience a reinforcement of beliefs via exposure to explicit adjectives. EEG data will be collected during reinforcement of beliefs. In the active control group, participants will receive no substance, but this group will follow the same procedure as the experimental groups with neutral adjectives. Participants will then perform isometric strength and fatigue resistance tests on an isometric dynamometer. EEG data as well as subjective data on expectations and rating of perceived exhaustion will be collected.

Conditions

• Placebo Effect
• Nocebo Effect

Interventions

COMBINATION_PRODUCT

Positive Expectation

The lead researcher will deliver a short presentation (8 minutes) to participants informing them about the deceptive substance, presenting it as a performance enhancing neurostimulant,. Participants will be given the opportunity to ask questions and will receive a handout of the key points of the presentation. After the presentation, participants will be set up with a high-density EEG and given two inert pills filled with cornstarch. Participants will be reminded of the performance enhancing qualities of the deceptive substance by implicit adjectives on a screen. Afterwards, experimental performance outcomes will be collected using a dynamometer.

COMBINATION_PRODUCT

Negative Expectation

The lead researcher will deliver a short presentation (8 minutes) to participants informing them about the deceptive substance, presenting it as a performance inhibiting neuro-depressant. Participants will be given the opportunity to ask questions and will receive a handout of the key points of the presentation. After the presentation, participants will be set up with a high-density EEG and given two inert pills filled with cornstarch. Participants will be reminded of the performance inhibiting qualities of the deceptive substance by implicit adjectives on a screen. Afterwards, experimental performance outcomes will be collected using a dynamometer.

OTHER

Control

The lead researcher will deliver a short presentation (8 minutes) to participants informing them about EEG research and set ups and give general information about isometric strength testing. They will be shown neutral adjectives unrelated to performance instead of implicit adjectives related to performance (experimental groups). EEG set up and strength testing remains the same as the experimental groups.

Sponsors & Collaborators

• Canterbury Christ Church University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-03-01

Primary Completion

2025-12-31

Completion

2025-12-31

Countries

• United Kingdom

Study Locations