This is a single center, 2-arm, patient-randomized study evaluating the feasibility and potential efficacy of the PRIMER intervention in improving physical function and reducing frailty in adult Liver Transplant candidates. The intervention will consist of a patient-tailored prehabilitation program designed to reduce frailty, improve physical function and nutritional status, and optimize pre- and post-transplant outcomes.

The investigator will pilot-test a two-arm, randomized trial of a prehabilitation intervention in 38 pre-liver transplant patients with End Stage Liver Disease (ESLD). The investigator estimates an attrition rate of 20%, resulting n=30 participants; 10 participants in Arm 1 (control arm) and 20 participants in Arm 2 (intervention arm). To be eligible, patients must be waitlisted or "Penn-Ready" with a MELD-Na less than or equal to 25, English-speaking, able to safely participant in an exercise program, have a smartphone, and be identified as frail. The purpose of this trial is to develop and implement a program of medical optimization, physical activity, and nutrition recommendations specifically tailored to ESLD and designed to reduce frailty, improve physical function, and optimize pre- and post-transplant outcomes.

Inclusion Criteria:

1. Participants must be wait-listed, in transplant evaluation, or "Penn Ready" with a MELD-Na score less than or equal to 25;
2. Patients must be English speaking and own/use a smartphone and cognitively able to consent;
3. Patient and physician feel that individual can safely participate in an exercise program;
4. Meeting at least one 'at risk' criterion for impaired physical performance, frailty, or malnutrition (by SPPB, abPG-SG, dynamometer measured grip strength), or physical deconditioning as determined by physical therapist, or treating clinician.

Exclusion Criteria:

1. The patient is unable to provide informed consent;
2. The patient has been hospitalized within the last 30 days;
3. A score of 0-3 points on the SPPB assessment indicating inability to participate in a physical activity program or a score of 12 in the absence of frailty or malnutrition (indicating low risk for poor physical or performance or malnutrition);
4. The patient is at risk for falling as defined by clinician assessment results or if the patient states that he/she has a history of falling (record of a fall(s) in the past 30 days);
5. The patient is already enrolled in a financial incentive-based exercise program using a wearable device;
6. Any other medical conditions that would prohibit participation in a physical activity program as determined by transplant clinicians or severe vision, hearing, or mobility impairment precluding participation.