What Makes Lee Sweeney Run?: In scientific circles, H. Lee Sweeney, PhD, chair of Penn's Department of Physiology, has built a reputation investigating Duchenne muscular dystrophy and hypertrophic cardiomyopathy. But he is best known in the wider world for his work with "mighty mice," treated to gain muscle mass and stave off many of the effects of aging. That work has drawn much attention — from The New York Times Magazine to competitive weight-lifters.