Acute Effects of Randori and Yakusoku Geiko in Young Judokas

August 28, 2026 updated by: Muhammed Sıddık Çemç, Bogazici University

Comparison of the Acute Effects of Randori and Yakusoku Geiko on Visual-Motor Performance and Heart Rate in Young Judokas

This study will compare the immediate effects of two common judo practice methods, randori and yakusoku geiko, on visual-motor performance and heart rate in young male judokas. Randori is a free-practice form of judo that involves active resistance and unpredictable interaction with an opponent, whereas yakusoku geiko is a more controlled practice method in which techniques are performed with less resistance.

The study will use a randomized, counterbalanced crossover design. The same participants will complete three conditions on separate days: randori, yakusoku geiko, and a seated rest control condition. The order of these conditions will be randomized, and there will be at least 48 hours between sessions.

Before and immediately after each condition, visual-motor performance will be assessed using the King-Devick Test, a rapid number-naming task that measures visual scanning, attention, and eye movement-related performance. Heart rate will also be measured before and immediately after each condition using a Polar H10 chest strap.

Randori and yakusoku geiko will each be performed for 4 minutes after a standardized warm-up. During the control condition, participants will rest for 4 minutes without performing physical activity. The study will examine whether these different judo practice conditions produce different immediate changes in King-Devick Test completion time, error count, and heart rate.

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.

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.
18

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.
  • Name: Muhammed Sıddık Çemç, Dr.
  • Phone Number: +90 537 016 29 25
  • Email: mscemc@gmail.com

Study Locations

  • Turkey (Türkiye)
    • Türkiye
      • Istanbul, Türkiye, Turkey (Türkiye), 34342
        • Boğaziçi University
        • Contact:
          • Muhammed Sıddık Çemç, Dr.
          • Phone Number: +90 537 016 29 25
          • Email: mscemc@gmail.com
        • Principal Investigator:
          • Muhammed Sıddık Çemç, Dr.

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:

Male participants. Licensed judo athletes residing in Istanbul. Regular participation in judo training at least three days per week. Willingness to provide informed consent. Willingness to avoid high-intensity exercise during the 24 hours before each testing session.

Exclusion Criteria:

Any known history of disease. Regular medication use. Failure to meet the study inclusion criteria.

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: Crossover Assignment
  • Masking: None (Open Label)

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: Sequence 1: Randori → Yakusoku Geiko → Control
Behavioral: Randori
Participants will complete a 4-minute randori session following an approximately 15-minute standardized warm-up. Randori will involve free judo practice with active resistance and unpredictable interaction between matched training partners. Participants will be paired with consideration of weight category and belt level.
Behavioral: Yakusoku Geiko
Participants will complete a 4-minute yakusoku geiko session following an approximately 15-minute standardized warm-up. Yakusoku geiko will involve controlled and repetitive judo technique practice with little or no active resistance from the training partner. Participants will be paired with consideration of weight category and belt level.
Experimental: Sequence 2: Randori → Control → Yakusoku Geiko
Behavioral: Randori
Participants will complete a 4-minute randori session following an approximately 15-minute standardized warm-up. Randori will involve free judo practice with active resistance and unpredictable interaction between matched training partners. Participants will be paired with consideration of weight category and belt level.
Behavioral: Yakusoku Geiko
Participants will complete a 4-minute yakusoku geiko session following an approximately 15-minute standardized warm-up. Yakusoku geiko will involve controlled and repetitive judo technique practice with little or no active resistance from the training partner. Participants will be paired with consideration of weight category and belt level.
Experimental: Sequence 3: Yakusoku Geiko → Randori → Control
Behavioral: Randori
Participants will complete a 4-minute randori session following an approximately 15-minute standardized warm-up. Randori will involve free judo practice with active resistance and unpredictable interaction between matched training partners. Participants will be paired with consideration of weight category and belt level.
Behavioral: Yakusoku Geiko
Participants will complete a 4-minute yakusoku geiko session following an approximately 15-minute standardized warm-up. Yakusoku geiko will involve controlled and repetitive judo technique practice with little or no active resistance from the training partner. Participants will be paired with consideration of weight category and belt level.
Experimental: Sequence 4: Yakusoku Geiko → Control → Randori
Behavioral: Randori
Participants will complete a 4-minute randori session following an approximately 15-minute standardized warm-up. Randori will involve free judo practice with active resistance and unpredictable interaction between matched training partners. Participants will be paired with consideration of weight category and belt level.
Behavioral: Yakusoku Geiko
Participants will complete a 4-minute yakusoku geiko session following an approximately 15-minute standardized warm-up. Yakusoku geiko will involve controlled and repetitive judo technique practice with little or no active resistance from the training partner. Participants will be paired with consideration of weight category and belt level.
Experimental: Sequence 5: Control → Randori → Yakusoku Geiko
Behavioral: Randori
Participants will complete a 4-minute randori session following an approximately 15-minute standardized warm-up. Randori will involve free judo practice with active resistance and unpredictable interaction between matched training partners. Participants will be paired with consideration of weight category and belt level.
Behavioral: Yakusoku Geiko
Participants will complete a 4-minute yakusoku geiko session following an approximately 15-minute standardized warm-up. Yakusoku geiko will involve controlled and repetitive judo technique practice with little or no active resistance from the training partner. Participants will be paired with consideration of weight category and belt level.
Experimental: Sequence 6: Control → Yakusoku Geiko → Randori
Behavioral: Randori
Participants will complete a 4-minute randori session following an approximately 15-minute standardized warm-up. Randori will involve free judo practice with active resistance and unpredictable interaction between matched training partners. Participants will be paired with consideration of weight category and belt level.
Behavioral: Yakusoku Geiko
Participants will complete a 4-minute yakusoku geiko session following an approximately 15-minute standardized warm-up. Yakusoku geiko will involve controlled and repetitive judo technique practice with little or no active resistance from the training partner. Participants will be paired with consideration of weight category and belt level.

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
Time Frame
Change in King-Devick Test Completion Time
Time Frame: Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions, with 48 hours to 7 days between sessions.
Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions, with 48 hours to 7 days between sessions.
Change in King-Devick Test Error Count
Time Frame: Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions, with 48 hours to 7 days between sessions.
Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions, with 48 hours to 7 days between sessions.

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
Time Frame
Change in Heart Rate
Time Frame: Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions.
Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions.

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.
Bogazici University

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 15, 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.
October 15, 2026

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.
October 30, 2026

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).
August 28, 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.
August 28, 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.
September 1, 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.
September 1, 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.
August 28, 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.
August 1, 2026

More Information

Terms related to this study

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.
  • E-84391427-050.04-297822

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because no formal data-sharing plan has been established for this study. Study findings will be reported in aggregate form in scientific publications and presentations.

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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