ABSTRACT Total joint arthroplasty (TJA) surgeries are among the most common elective surgeries in the US and projected to increase in frequency. Recent TJA clinical practices have effectively reduced post-operative hospital length of stay, yet despite improvements in the efficiency of TJA care, the effects of TJA surgical procedures on pulmonary and respiratory muscle function are less widely appreciated. Even during surgeries as short as TJA, the administration of anesthesia, neuromuscular inactivity, and mechanical ventilation acutely deteriorate pulmonary function and trigger rapid, significant proteolysis of the primary inspiratory muscle, the diaphragm. However, conventional TJA preoperative care does not conventionally address these issues. Older adults, smokers, and those with significant pre-existing lung disease, multiple medical comorbidities, or socioeconomic disadvantage face the greatest risk for declines in post-operative pulmonary and respiratory neuromuscular function. Most patients who utilize our urban safety-net academic medical center have at least one of these risk factors, which can interfere with acute rehabilitation, increase the risk for post-operative pulmonary complications, and extend hospital length of stay. Thus, we propose a clinical study of preoperative inspiratory muscle training (IMT) among individuals with increased risk for pulmonary post-operative complications. Preoperative IMT has been shown to counteract post-operative inspiratory weakness and reduce postoperative pulmonary complications following prolonged cardiac surgeries, but its potential benefits have not been investigated in shorter surgeries such as TJA, with expected brief post-operative hospitalizations. The central hypothesis of this project is that preoperative IMT is feasible and will improve respiratory strength, hasten the early postoperative respiratory recovery, and optimize functional mobility for hospital discharge. Adults scheduled for TJA with pre-existing respiratory muscle or lung impairment will be randomized to complete either: daily IMT in advance of surgery (dIMT), a single acute IMT session immediately before surgery (aIMT), or usual surgical standard of care (SOC). Follow-up testing on the day of surgery and during the acute post-operative hospitalization will identify the feasibility of IMT (Aim 1), distinguish IMT effects on inspiratory and cough strength, (Aim 2), and evaluate patient readiness for discharge (Aim 3). This high risk, proof-of-principle proposal will provide the first controlled evidence concerning disturbances in the regulatory functions of breathing following TJA. Our plan is that data generated from this study will form the basis for future mechanistic studies of IMT to restore breathing strength and further optimize early rehabilitation following TJA.