The Influence of Explosive Strength, Isokinetic Potential, and Stability on the Performance Success of the Uchi-mata Throw Technique in Students

Abstract

The aim of this study was to determine the influence of explosive strength, isokinetic muscle potential, and stability on the success of performing the Uchi-mata throwing technique in students (n = 57) from the Faculty of Sport and Physical Education, University of Sarajevo, who were systematically introduced to judo for the first time through the teaching process. The predictor variables included indicators of explosive strength (countermovement jump—CMJ, squat jump—SJ, and countermovement jump with arm swing—CMJFA), isokinetic peak torque of relevant muscle groups at 30°/s and 60°/s, and stability indices (overall stability index—BOSI, anteroposterior stability index—BAPSI, and mediolateral stability index—BMLSI). The criterion variable was defined as the first principal component extracted from the ratings of three expert evaluators. Hierarchical regression analysis showed that explosive strength alone was not a statistically significant predictor (R² = .093, p = .155), whereas the full model (explosive strength + isokinetic potential + stability) explained 62.4% of the variance in performance success (R = .79, R² = .624, p = .007). Significant partial predictors were peak torque of plantar flexion in the dominant ankle (β = −1.044, p < .001), elbow extension of the dominant arm (β = −0.668, p = .007), and the overall stability index (BOSI). These findings indicate that technical proficiency in Uchi-mata among novice students is not determined by general explosive strength, but rather by the functional integration of specific maximal force and postural stability within a properly acquired biomechanical movement pattern. The results have practical implications for planning and programming judo instruction in the initial stages of learning, with an emphasis on developing specific isokinetic strength and stability.