Acute Effects of Randori and Yakusoku Geiko 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.