Wearable tDCS and Acute Golf Shot Performance

Overview

Transcranial direct current stimulation (tDCS) has been investigated as an ergogenic aid for two decades, but most sport evidence comes from laboratory stimulators operated by experimenters. This trial evaluates whether a single 20-minute session of wearable, app-controlled bilateral motor-cortex tDCS (Halo Sport 2, 2 mA) improves full-swing golf shot performance compared with sham stimulation. The study is a double-blind, sham-controlled, parallel-group randomized trial with a pre-test/post-test design in golfers stratified into professional, amateur-high, and amateur-middle skill groups. Each participant attends a single session comprising a 40-shot pre-test, 20 minutes of real or sham stimulation, and a 40-shot post-test, with shots measured by a TrackMan 4 launch monitor across eight standardized club categories. The primary outcomes are change scores (post minus pre) in carry distance, ball speed, smash factor, within-player carry-distance variability, and absolute lateral deviation. Effects will be examined overall and as a function of skill level (categorical group and continuous golf handicap).

Participants are stratified by skill level (professional, amateur-high, amateur-middle) and sex, and randomly assigned 1:1 to real or sham stimulation using a computer-generated sequence; allocation is concealed from the testing team. Real stimulation: Halo Sport 2 headset, bilateral primary motor cortex (approximately C3/C4), 2 mA for 20 minutes (30-s ramp up and down), controlled by smartphone app. Sham: identical device and app procedure with a 30-s current ramp-up followed immediately by ramp-down and no sustained current; the app does not display the stimulation mode. Each participant attends one session: 10-min standardized warm-up, 40-shot pre-test, 20-min stimulation, 40-shot post-test. Shot outcomes (carry distance, ball speed, smash factor, spin rate, launch angle, launch direction, club speed, attack angle, face-to-path) are recorded with a TrackMan 4 launch monitor; within-player variability (SD of five shots) is computed per club category (Driver, 3-wood, hybrid, 5-iron, 7-iron, 9-iron, 70-yd wedge task, 100-yd wedge task). Analyses use linear mixed models with likelihood-ratio tests; skill-dependent moderation is tested categorically (group) and continuously (handicap linear and quadratic interactions) with false-discovery-rate correction. Anonymized participant-level data and analysis scripts will be made available in a public repository (Zenodo, https://doi.org/10.5281/zenodo.22684611).