Professor Saltzman begins the lecture with discussion of the importance of motion for the survival and propagation of any living species. He presents the different modes of motion, taking first the example flight to talk about force balance, such as the magnitude of propulsive force that must be generated overcome drag to produce forward motion. Next, the mechanics of walking, running, cycling and swimming is discussed, with emphasis on efficient use of energy, overcoming drag and friction, and the influence of organism shape and size. An equation to calculate drag force of a spherical object of radius, r, moving at velocity, v, in a medium with viscosity, μ, is introduced: Fd = 6πvμr. Finally, Professor Saltzman talks about design of the artificial hip, which biomedical engineers must take into consideration the biomechanics and natural function of the pelvic bone.