Earth-based Implications: Prolonged inactivity is inherent to trauma, serious injury, or major surgery. These events represent a significant stress to the patient such that the resultant muscle loss and weakness impairs subsequent rehabilitation. The requirement for hospital intensive care often entails hypocaloric intake in the patient, thereby further exacerbating the deleterious effects of hospitalization. This project was designed to investigate countermeasures that will maintain muscle mass and function during periods of prolonged inactivity. The proposed interventions are primarily nutritional, with the idea that minimal activity will enhance nutritional effectiveness. The nutritional intervention is of unique design and composition so as to have a maximal benefit on a gram per gram basis. Thus, these investigations are directly applicable and translatable to patient populations.