Multiple Sessions of Transcranial Direct Current Stimulation Combined With Squat Training Improve Lower-Limb Maximum Strength in Healthy Adult Men

Yan, X, Zuo, Z, Nitsche, MA, Zhang, X, and Qi, F. Multiple sessions of transcranial direct current stimulation combined with squat training improve lower-limb maximum strength in healthy adult men. J Strength Cond Res XX(X): 000–000, 2026—This study aimed to investigate the effects of transcranial direct current stimulation (tDCS) combined with Squat training (ST) on lower-limb maximum strength in healthy adult men. Sixty men (age: 21.6 ± 2.1 years, height: 177.5 ± 5.3 cm, body mass: 73.1 ± 7.4 kg) were randomly assigned to 4 groups (tDCS + ST group, sham tDCS + ST group, tDCS + rest group, sham tDCS + rest group). The 6-week intervention program was implemented with biweekly sessions, totaling 12 treatment sessions, each separated by a minimum 48-hour interval. After the tDCS intervention, the ST groups performed squat exercises while the tDCS + rest and sham tDCS + rest groups sat quietly for 30 minutes. Lower-limb maximal muscle strength was measured at 4 distinct time points: preintervention (T0), 24 hours post-third week intervention (T1), 24 hours post-sixth week final session (T2), and 1 week post-entire intervention completion (T3). Key evaluation metrics were measured, including 1 repetition maximum (1RM) squat, knee extensor and flexor peak torque, and rectus femoris cross-sectional area (CSA). Significant improvements in 1RM, knee extensor strength, and nondominant rectus femoris CSA were observed in both tDCS + ST and sham tDCS + ST groups compared with the sham tDCS-only group ( p < 0.05). No differences in knee strength, 1RM, or rectus femoris CSA were observed between the tDCS + rest and sham tDCS + rest groups. The results indicate that anodal tDCS combined with ST does not yield additional training benefits on lower-limb maximal strength in healthy adults when compared with ST alone.