<p>This study aimed to evaluate whether simultaneous training involving complex gait and cognitive tasks is more effective than separate training in improving frontal lobe function and reducing dual-task interference, as a potential cognitive rehabilitation strategy. In a randomized controlled trial (<i>n</i> = 24), conducted in accordance with CONSORT guidelines, participants were assigned to simultaneous or separate training for 24 sessions (5 weeks, each 50&#xa0;min) and primary outcomes included changes in the Frontal Assessment Battery (FAB) and Dual-Task Cost (DTC). Both groups improved in total FAB score, with a larger effect size (Hedges’ g) in the simultaneous group than in the separate group (1.12 vs. 0.48). At the subscale level, the simultaneous-training group showed statistically significant changes across all six FAB subtests (<i>p</i> &lt; 0.05), whereas the separate-training group improved only in Lexical Fluency (<i>p</i> = .0 .025). Because <i>p</i> values for FAB subscales are unadjusted and reported for exploratory purposes, these subscale findings should be interpreted with caution. No between-group differences were observed in gait-related DTC (<i>p</i> = 0 .891), whereas cognitive DTC decreased significantly in the simultaneous-training group (<i>p</i> &lt; 0 .001). The effect size for cognitive DTC was 1.64. These findings suggest that simultaneous training, characterized by sustained temporal overlap between gait and cognitive tasks, preferentially enhances executive coordination and cognitive interference management under concurrent task demands. The observed effects are interpreted at the behavioral and task-processing level, supporting task structure as an active ingredient of training rather than implying underlying neurophysiological mechanisms.</p>