Anodal Motor-Cortex Transcranial Direct Current Stimulation and Explosive Lower-Limb Power in Healthy Active Adults: A Sham-Controlled Systematic Review and Meta-Analysis.

Anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been proposed as an ergogenic aid. Prior reviews pooled heterogeneous outcomes, and none isolated explosive lower-limb power or separated jump output from force-time kinetics. We asked whether anodal M1 tDCS versus sham improves explosive lower-limb power in healthy active adults, analysing these two outcome categories separately. Following PRISMA 2020 (PROSPERO CRD420261438841), four databases were searched up to 3 July 2026 for randomised and crossover trials. Random-effects meta-analyses (REML with Hartung-Knapp) pooled Hedges' g by category; risk of bias (RoB 2) and certainty (GRADE) were assessed. Seven trials were included. tDCS did not significantly improve jump output (k = 6; g = 0.44, 95% CI -0.05 to 0.92; p = 0.069; I2 = 19%). The kinetics estimate was moderate (k = 3; g = 0.67, 95% CI 0.53 to 0.81; I2 = 0%) but did not survive a conservative small-sample correction (95% CI -0.23 to 1.57; p = 0.086). Certainty was very low throughout. Including a further trial whose comparator was a no-intervention control made both estimates significant, indicating a fragile evidence base. Current evidence does not establish an ergogenic benefit; adequately powered, pre-registered trials are needed.