Older, critically ill patients who survive their ICU stay frequently develop post-ICU syndrome (PICS) - a condition manifested by sarcopenia, weakness, malnutrition and neurocognitive decline - which occurs as a result of a critical illness, prolonged bed rest, catabolism, and polypharmacy. PICS frequently leads to chronic disability, prolonged mechanical ventilation (MV), functional deficits, and the need for extended rehabilitation in long term care facilities (LTCs). As the majority of patients admitted to ICUs are ≥ 65 years old, many of these patients are at high risk for PICS. Since the care of ICU patients is primarily focused on the medical management of the acute critical illness, there are limited resources and strategies available to prevent PICS. Evidence suggests mobility-based physical rehabilitation (MPR) combined with resistive training with neuromuscular electric stimulation (NMES) and high protein diets (HPRO) containing essential amino acids can mitigate the loss of muscle mass and function during bed rest in the elderly. The investigators hypothesize that preventive therapy involving the addition of both NMES and HPRO to MPR early and throughout the ICU and hospital stay can mitigate PICS-associated sarcopenia, malnutrition, and immobility to confer valuable health benefits toward recovery. To test this, the investigators will use a 2x2 factorial design in which older, MV ICU patients will all receive comprehensive ICU care and MPR, then be randomized to one of 4 groups: 1) MPR+NMES, 2) MPR+HPRO, 3) all 3 together, or 4) MPR alone (control), to determine independent and combined effects of the interventions.