The effect of six weeks of squat training on static and dynamic postural control: a randomized controlled trial of adjunctive tDCS.

BACKGROUND: Postural control depends on central sensorimotor integration. Combined transcranial direct current stimulation (tDCS) is a promising neuro-modulatory strategy to augment training, evidence for its long-term efficacy in enhancing postural control remains limited and inconsistent. OBJECTIVE: To determine whether 6 weeks of squat training (ST) combined with anodal tDCS (a-tDCS) results in synergistic benefits to postural control in healthy adults. METHODS: Forty-eight participants were randomized into four groups: a-tDCS + ST, sham tDCS + ST, a-tDCS, and a sham tDCS. During the 6-week intervention, participants received primary motor cortex (M1) targeted anodal or sham stimulation. The ST groups performed barbell squats at 85% of their one-repetition maximum (1 RM). Posturography was assessed via Sensory Organization Test (SOT), Motor Control Test (MCT), and Unilateral Stance (US) at baseline (T0), 3 weeks (T1), and 6 weeks (T2) during the intervention, in addition to 1 week post-intervention (T3). RESULTS: The sham tDCS + ST group significantly improved in SOT composite scores and US with eyes closed (ECL) compared to the a-tDCS and sham tDCS at T2 and T3, with significant within-group gains from baseline. The a-tDCS + ST group showed significant within-group improvements in SOT and ECL at T2 and T3. In US with eyes open, the sham tDCS + ST group outperformed the a-tDCS group in EOL at T3, and both ST groups showed significant within-group improvements. No significant additive benefit of a-tDCS was observed when comparing the a-tDCS + ST group with the sham tDCS + ST group across SOT, MCT, and US measures. CONCLUSIONS: Six weeks of squat training significantly improved dynamic and static postural control. Adjunctive a-tDCS applied over M1 prior to training failed to augment these benefits under the current parameters.