Cachexia, muscle wasting and weakness are common in individuals infected with HIV, and are associated with increased mortality. Our primary purpose is to describe the perturbations in protein metabolism that explain the muscle wasting associated with HIV infection by determining the rates of whole body and skeletal muscle protein turnover, using stable isotope tracer methodology. Our second purpose is to determine whether two potential anabolic interventions (weight lifting and growth hormone treatment) can alter the rates of protein synthesis and breakdown such that increments in fat-free mass, muscle mass and muscle strength occur.