Statistical analysis
CORTEX
The SPSS statistical package, version 26.0 (IBM, SPSS, Inc., Chicago, IL) was used for data analysis. The normality of data distribution and homogeneity of variance were examined with Shapiro–Wilk and Levene tests. 2 × 3 repeated-measures ANOVAs were conducted with task-specific peak performance parameters (power speed (Broad Jump Test), strength/coordination (Straddle lift to handstand Test), endurance (Double Legs circle Test), static strength (Back Hang Scale Test), dynamic strength (Dips on Parallel Bars), flexibility (dynamic) (Active Shoulder Flexibility Test), flexibility (static) (Sit and Reach Test), and physical activity intensity (Rating of Perceived Exertion) as dependent variables, and time (pre-intervention, post-intervention) and stimulation condition (bilateral anodal tDCS over the pre-motor cortex; bilateral anodal tDCS over the cerebellum, and sham tDCS over the cerebellum or pre-motor cortex) as the within-subject factors. For EMG parameters, a within-subject repeated-measures ANOVA was conducted with stimulation condition as the within-subject factor. This measurement was conducted only during stimulation (last 5 min of stimulation) and thus no baseline was available. Before the ANOVA, Mauchly’s test was used to check the sphericity of the data. When this assumption was violated, a Greenhouse–Geisser correction was used. Conditional on significant results of the ANOVA, Fisher’s LSD post hoc tests (paired-sample, two-tailed) were performed for post hoc analysis.