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

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

18

Phase

  • 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

  • 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

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
Intervention / Treatment
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

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

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

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)

September 15, 2026

Primary Completion (Estimated)

October 15, 2026

Study Completion (Estimated)

October 30, 2026

Study Registration Dates

First Submitted

August 28, 2026

First Submitted That Met QC Criteria

August 28, 2026

First Posted (Actual)

September 1, 2026

Study Record Updates

Last Update Posted (Actual)

September 1, 2026

Last Update Submitted That Met QC Criteria

August 28, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Other Study ID 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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