My research focuses on the theme of muscle biology, currently spanning from the gross to the molecular levels of analysis. I have a long standing interest in the flight of bats, in part motivated out of curiousity about how bat muscles produce high frequency, powerful movements, and yet remain remarkably resistant to fatigue. Our studies have identified recruitment patterns, histochemical profiles, and physiological characteristics of the major flight muscles in a number of bat species. Recently, our laboratory has been performing an integrated structural-functional analysis of the appendicular muscles in horses and bats, as well as in a diversity of other species. The goal of these studies is to develop a comparative biology of muscle in several of Nature's better "athletes." For horses, our goal is not only to understand the biomechanics of locomotion. But, we also look at possible muscle involvement in gait abnormalities. In both horses and bats, we have sought to correlate specializations of the major contractile protein, myosin, with phylogenetic or architectural/functional constraints. In all these somewhat divergent studies, the major themes come back to the role of muscle groups in locomotion, and the elucidation of interactions between nerves and muscles in affecting the phenotype of mature muscle.