PROJECT SUMMARY ABSTRACT This study aims to evaluate the potential role of physical therapy (PT) in improving outcomes after ventral hernia repair. The long-term goal is to develop therapies to improve function of the abdominal core musculature and to regain quality of life considering the abdominal core?s inter-related components. Our central hypothesis is that patients undergoing a specific type of hernia repair, ventral hernia repair, will have measurably improved functional capacity and quality of life following rehabilitation that addresses the mechanism of both loss and gain of abdominal core function. The rationale for this project is a novel conceptual model that enables innovative therapies incorporating abdominal core function as the summative functions of the abdominal wall, lower back, diaphragm, and pelvic floor, which contribute to activities of daily living and quality of life. The central hypothesis will be tested with a feasibility randomized controlled trial of standardized post-operative physical therapy that pursues three specific aims: 1) establish the efficacy of post-operative physical therapy to improve function and patient-reported outcomes after ventral hernia repair; 2) establish the feasibility of post-operative physical therapy to improve functional and clinical outcomes in individuals undergoing ventral hernia repair; and 3) determine whether baseline abdominal core function influences the efficacy of post-operative physical therapy after ventral hernia repair. This prospective registry-based RCT will leverage current infrastructure within the Abdominal Core Health Quality Collaborative, a national registry of patients with hernia disease and diseases of the abdominal wall, to collect key clinical measures along with additional measures of function added for this study. A standardized PT protocol will be administered to a randomized group of participants. Under the first aim, function is primarily assessed using the Five Times Sit-to-Stand, and patient-reported outcomes using the PROMIS-Physical Function survey. Primary timepoints include pre-op and 10 weeks post-op at the conclusion of rehabilitation, with additional timepoints at 30 days, 6 months and 1-year post-op. For the second aim, we strive to assess the feasibility of the registry-based RCT design and postoperative physical therapy by measuring retention and compliance rates. For the third aim, we will use our novel quantitative, continuous abdominal core function assessment (QUeST) at primary and intermediate timepoints to help identify those who may benefit most from postoperative PT. The research proposed is innovative because it breaks down silos of expertise and structures examined. It leverages diverse and complementary perspectives from different surgical and rehabilitation specialties in a holistic manner. This contribution is expected to be significant as it will lead to a well-powered definitive multi-center clinical trial to reduce the medical and societal burden of ventral hernia on the US population.