Acute Effects of High- Versus Low-Elevation-Gain Trail Running Training on Static and Dynamic Postural Balance in Young Trail Runners

Background: Trail running is a sport characterized by taking place in natural environments and requiring constant adaptation to irregular terrain, making postural balance crucial for preventing falls and coping with the coordinative demands of these races. Objectives: This study aimed to analyze the acute effects of elevation on dynamic and static balance in young trained trail runners. Methods: Fifteen highly trained young athletes (eight females, seven males; age 16.8 ± 2.14 years) completed two similar training sessions except for elevation gain (1000 m vs. 15 m, flat). Static balance was evaluated using the Balance Error Scoring System (BESS), and dynamic balance was assessed with the Y Balance Test (YBT) before (pre) and after each session (post) using 2 × 2 (Time × Terrain) repeated-measures ANOVA. Results: BESS errors increased in both sessions but more after elevation (+3.33 vs. +1.20 errors; interaction p < 0.001; post-session 15.67 ± 1.23 vs. 12.67 ± 1.23). The YBT composite index showed no significant differences between elevation and flat sessions (83.32 ± 7.92 vs. 83.79 ± 7.59, p = 0.763) or in the interaction (p = 0.057). Conclusions: These findings highlight the need for specific strategies to preserve postural balance—especially static balance—during training and after trail races and support taking elevation gain into account when programming training load in young trail runners.