An interventional study of Randori and Yakusoku Geiko in Visual Performance, Heart Rate Response and Judo Performance, sponsored by Bogazici University. Not yet recruiting at 1 site in Turkey (Türkiye). Open to male participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-01.
Sponsored by Bogazici University · Not applicable, Interventional, and Basic science
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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.
Bogazici University is the lead sponsor of 5 studies on the registry; 2 are open to participants now.
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Male participants. Licensed judo athletes residing in Istanbul. Regular participation in judo training at least three days per week. Willingness to provide . 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.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Behavioral: Randori · Behavioral: Yakusoku Geiko
Behavioral: Randori · Behavioral: Yakusoku Geiko
Behavioral: Randori · Behavioral: Yakusoku Geiko
Behavioral: Randori · Behavioral: Yakusoku Geiko
Behavioral: Randori · Behavioral: Yakusoku Geiko
Behavioral: Randori · Behavioral: Yakusoku Geiko
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.
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.
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.
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.
Change in Heart Rate
Time frame: Immediately before and immediately after each study condition (randori, yakusoku geiko, and control) during three separate testing sessions.
Plan to share: No — 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.
No publications or documents are linked to this record.
Start is estimated for Sep 2026; primary completion for Oct 2026, 1 month later.
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This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Bogazici University