Performance of unstable barbell bench press and changes in electromyographic activity after transcranial direct current stimulation

• Transcranial direct current stimulation did not significantly alter the number of repetitions in unstable barbell bench press, indicating no effect on muscle endurance. • True transcranial direct current stimulation significantly reduced Y-axis acceleration amplitude, suggesting improved movement stability during the task. • Anodal transcranial direct current stimulation increased activation of the anterior deltoid and co-activation of the posterior deltoid, potentially enhancing shoulder joint stiffness. • No significant interaction was found between transcranial direct current stimulation and exercise phase, indicating that the effects were consistent across the movement. • Transcranial direct current stimulation may be a useful adjunct in sports and rehabilitation to improve stability in unstable resistance exercises.