My primary interests reside in the area of comparative biomechanics and physiology. My research program quantifies whole animal performance in general and locomotion in particular as it relates to an animal's structure, physiology, and behavior. We use biomechanical, computer simulation (dynamic musculo-skeletal modeling), physical modeling (robot and artificial muscle construction), isolated muscle, biochemical, whole-animal exercise physiology and field-tracking techniques to seek general design principles for species which have evolved different solutions to the problems of locomotion and activity in general. The study of arthropod, amphibian and reptilian locomotion continues to offer an excellent opportunity for comparison. Animals such as crabs, cockroaches, ants, beetles, scorpions, centipedes, geckos and salamanders show tremendous variation in body shape, gas transport system, leg number, musculoskeletal arrangement and mode of movement. Diversity enables discovery. We use these "novel" biological designs as natural experiments to probe for basic themes concerning the relationship between morphology, body size, energetics, dynamics, control, stability, maneuverability, maximum speed and endurance. An understanding of the diverse biological solutions to the problems of locomotion contributes to the development of a general theory of energetics, neuro-mechanics and behavior. We collaborate closely with engineers, mathematicians and computer scientists by providing biological principles to inspire the design of multi-legged robots, artificial limbs and muscles, novel control algorithms, and self-cleaning, dry adhesives.