Background <p>Pain after breast plastic surgery affects quality of life. Physical therapy offers effective interventions for this condition, such as transcutaneous electrical nerve stimulation (TENS). Although this resource has been used for more than 20&#xa0;years, no studies have been published that support its use following this type of surgery. Therefore, the aim of the proposed study is to evaluate the effect of TENS on pain intensity in patients undergoing mastopexy with implants, given the existing evidence on the success of TENS for other conditions.</p> Methods <p>A two-arm, randomized, sham-controlled trial will be conducted with blinded assessors. The study will be carried out at the Exercise Physiology and Metabolism Lab of Finis Terrae University. Eligible participants will be women undergoing mastopexy with implants invited by a board-certified plastic surgeon. The participants will be randomly assigned to one of two study groups: Group 1 (surgery + TENS) and Group 2 (surgery + sham TENS). TENS will be administered only 1 h after surgery and will remain for 1 h. Four assessments will be performed: before treatment (T0), immediately after treatment (T1), 1 h (T2), and 4 h after TENS (T3). The primary outcome will be pain intensity at rest, pain intensity during movement (standardized movements of both arms: anterior flexion, abduction, and external rotation), and during respiratory function tests. Secondary outcome measures will be maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), and vital capacity (VC).</p> Discussion <p>In this study, the effects of TENS on patients with pain following mastopexy with implants will be compared to the effects of a sham TENS intervention. This RCT will offer novel evidence on the potential benefits of TENS in terms of pain intensity at rest as well as during movements and respiratory function tests.</p> Trial registration <p>ClinicalTrials.gov NCT06202794. Registered on January 11, 2024.</p>