Effects of o-tDCS and tDCS on maximal grip strength

Objective: The aim of the current study was to examine and compare the effects of oscillatory transcranial direct current stimulation (o-tDCS) and transcranial direct current stimulation (tDCS) against sham stimulation on maximal intermittent gripping performance. Materials and Methods: The study included 25 healthy, right-handed male subjects (age range 18-35 years) who were randomly assigned to three separate groups: o-tDCS (n=9), tDCS (n=8) and sham (n=8). The left primary motor cortex was selected as the anodal stimulation region, and a cathode electrode was placed over the right supraorbital area. A hand dynamometer is used to measure the maximum grip values during a maximal intermittent gripping task. Between-group comparisons were made; for each stimulation group, baseline grip values of the participants were compared with those obtained during stimulation. Results: Although the o-tDCS group showed slightly better improvements in maximal and mean strength, there were no statistically significant differences between stimulation groups (p>0.05). Conclusion: The findings of the study suggest neither o-tDCS nor tDCS has a significant facilitative impact on grip strength values in healthy young males, most likely due to a ceiling effect in this population.