Effects of plyometric training combined with tDCS on lower-limb muscle activation and cardiopulmonary function in male amateur soccer players: a randomized controlled trial

[Purpose] This study aimed to investigate the effects of combining transcranial direct current stimulation (tDCS) with plyometric training on lower-limb muscle activation and cardiorespiratory function in male amateur soccer players.[Methods] Thirty male amateur soccer players were randomly assigned to an experimental group (n = 15) or a control group (n = 15). The experimental group performed plyometric training combined with transcranial direct current stimulation (tDCS), whereas the control group performed plyometric training with sham stimulation. The intervention was conducted three times per week for four weeks. Lower-limb muscle activation (RF, VL, VM, and GCM) and cardiorespiratory function (MIP, MIFR, VO2max, Wmax, and MEC) were assessed before and after the intervention. Data were analyzed using a two-way mixed-design ANOVA.[Results] Both groups showed significant within-group improvements in muscle activation and cardiorespiratory variables (p < 0.05). However, the experimental group demonstrated significantly greater enhancements in RF, VL, VM, and GCM activation compared with the control group (p < 0.05). Between-group comparisons also revealed superior improvements in MIFR and Wmax in the experimental group (p < 0.05), while VO2max increased significantly over time in both groups without between-group differences. A two-way mixed-design ANOVA indicated significant group × time interactions for muscle activation and selected cardiorespiratory indices (p < 0.05), supporting enhanced neuromuscular and physiological adaptations in the experimental group.[Conclusion] Combining tDCS with plyometric training enhanced lower-limb muscle activation and cardiorespiratory function more effectively than plyometric training alone in amateur soccer players.