Can Transcranial Direct Current Stimulation Improve Counter-movement Jump Performance ?

Abstract

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique and has been known to reliably alter motor cortical excitability. Anodal stimulation increases cortical excitability and cathodal stimulation inhibits cortical excitability. However, the effects of tDCS on counter-movement jump (CMJ) is currently unknown. PURPOSE: The aim of this study was to investigate the effects of tDCS on CMJ performance in healthy men. METHODS: A double-blinded crossover design was used. Fourteen male subjects (age: 22 ± 2 yrs, height:174.43 ± 5.74 cm, weight: 68.66 ± 9.47 kg) received three time stimulations, each time an anodal tDCS (a-tDCS) or cathodal tDCS (c-tDCS) or sham tDCS randomly. The electrodes are placed over primary motor cortex (M1) bilaterally and the opposite electrodes pair over the ipsilateral shoulders. Each stimulation lasted 20 min, 48-72 hours apart and current was set at 2mA. Participants were required to get anthropometric measurements and familiar with CMJ in advance. Then, completed five CMJ tests before and after each stimulation, with one minute recovery interval between each test. The best three of the five CMJ in each moment was selected for analysis. Two-way (condition × time) ANOVA with repeated measures were used for CMJ height, flight time, and initial velocity. SUMMARY OF RESULTS: There was a significant interaction between condition and time for CMJ height (F(2,39) = 7.948, p < 0.001), flight time (F(2,39) = 8.228, p < 0.001), and initial velocity (F(2,39) = 8.375, p < 0.001). There were no significant mains effects for condition or moment for any of the outcome measures (p > 0.05). Post-hoc analysis showed that there were no significant differences between conditions both on pre- and post-stimulation moments (p > 0.05). However, post a-tDCS performance was significantly superior to pre a-tDCS for CMJ height, flight time and initial velocity (p < 0.001 for all). There were no significant pre-post changes in both c-tDCS and sham-tDCS conditions (p > 0.05 for all). CONCLUSION: Our findings demonstrate that anodal tDCS may be a valuable tool to enhance vertical jumping ability, which is very important for huamn sport performance.