Does fatigue mask directional performance asymmetry? Preferred and non-preferred throwing-side differences during judo-specific tasks in young judo athletes

The

Aim: of this study was to examine whether fatigue influences performance differences between the preferred and non-preferred throwing sides during judo-specific tasks in young judo athletes. Twenty-eight competitive judo athletes completed the Special Judo Fitness Test (SJFT) and a high-intensity intermittent uchi-komi protocol on both their preferred and non-preferred throwing sides. Performance output, heart rate (HR), and ratings of perceived exertion (RPE) were recorded during exercise and recovery. In the SJFT, athletes completed more total throws on the preferred side (p 0.05). The SJFT asymmetry index did not change significantly across series (p=0.71, Kendall’s W=0.01). During the intermittent uchi-komi protocol, athletes completed more repetitions on the preferred side (p<0.001, Hedges’ g=0.60), but this side-related difference decreased across sets (side × set interaction: p<0.001, η²=0.04), with repetition counts becoming comparable in the later sets. This pattern was supported by a reduction in the repetition-based asymmetry index across sets (p=0.002, Kendall’s W=0.14). Although absolute HR (p<0.05, η²=0.05) and RPE (p<0.001, η²=0.07) were higher on the preferred side, the HR-to-repetition ratio was lower on this side (p=0.03, η²=0.07). These

Findings: indicate that side-related performance advantages in judo are task-dependent and may become less pronounced during repeated high-intensity technical actions, supporting the use of fatigue-aware and bilateral assessment strategies in young judo athletes.