水中環境における感覚運動課題中の皮質抑制と活性化：熟練者・初心者パラダイムに基づくパイロットEEG研究

This study aimed to investigate cortical inhibition and activation during sensorimotor task performance in an aquatic environment using an expert-novice paradigm (national-level athletes vs. non-athlete controls).

Twelve national-level athletes and twelve age- and gender-matched controls completed a repetitive elbow flexion-extension task under both aquatic and terrestrial conditions. 64-channel EEG data were collected to measure sensorimotor rhythms (SMR) power at the Cz electrode, as well as the mean frequency (MF) and task-to-baseline power ratios of theta, alpha, and beta bands across the frontal, frontal-central, central, central-parietal, and parietal regions. Both within-group and between-group comparisons were performed.

The main results showed that the swimmer group exhibited a significant reduction in SMR power during an aquatic task, while no significant change was observed in a terrestrial task. In contrast, the control group showed significant reductions in SMR power under both conditions. In beta-band activity, both groups showed significantly increased MF in task conditions. Task-related beta power in both groups remained broadly comparable to the resting baseline, with no obvious decrease. In attention, the control group showed a slight increase in MF and task-related beta power during the aquatic task compared to the terrestrial condition, whereas the swimmer group showed comparable or slightly lower MF and task-related power in the aquatic environment.

These findings suggest that, through long-term training, swimmers develop enhanced sensorimotor adaptation during movement in aquatic environments. This adaptation appears to involve environment-specific cortical activation patterns, which may further facilitate motor execution in water.