PROJECT SUMMARY Multiple myeloma is the second most prevalent hematologic malignancy in the US with an estimated 7.1 cases per 100,000. Patients diagnosed with multiple myeloma have improved survival with autologous stem cell transplant (ASCT), however high symptom burden, including reduced muscle strength, is still highly prevalent and results in worsened clinical outcomes due to progressive age-related comorbidities and frailty. Despite advances in ACST, there are limited non-pharmacologic prehabilitative intervention strategies to augment physical fitness through improved muscular strength and minimize the risk of unfavorable clinical outcomes. Prehabilitation exercise-based programs do not exist in the current standard of care for ASCT in multiple myeloma. Developing supportive individualized care interventions that target maximizing functional status would be of great benefit to patients with multiple myeloma whose extended survival is heavily impacted by the chronic burden of their cancer therapies. The objectives of the proposed research sub-analysis of the ongoing PROTECT trial, designed with the primary goal of assessing feasibility of exercise, are to examine the effects of an 8-week home-based, virtually supervised prehabilitative exercise intervention on (1) muscle strength, (2) patient health outcomes including physical capacity, patient reported outcomes, and cardiometabolic health outcomes, and (3) clinical outcomes in 30 patients with multiple myeloma undergoing ASCT being treated at the Dana-Farber Cancer Institute. Our central hypothesis is that muscle strength will be improved over the course of an 8-week prehabilitative exercise training program in patients with multiple myeloma. We also hypothesize that exercise will improve patient health outcomes and clinical outcomes. The impact of the proposed research lies in providing an effective pre-transplant intervention that can improve muscle strength, patient health outcomes and postoperative clinical outcomes in patients with multiple myeloma receiving ASCT. This sub-analysis will establish foundational knowledge to conduct a larger-phase clinical trial to test clinical benefits of prehabilitation exercise in patients with multiple myeloma undergoing ASCT. The proposed F31 training fellowship aims to leverage my background in biology and exercise physiology for investigating the effects of an exercise intervention in multiple myeloma patients. Through this fellowship, I aspire to align my research efforts with my long-term career goal of becoming an independent clinical researcher specializing in exercise physiology and cancer prevention/survivorship. The dedicated time and support will establish strong mentorship and facilitate the acquisition of essential skills and knowledge necessary to make significant contributions to the field of exercise oncology.