The earliest studies of intermittent exercise physiology noted that moving intermittently (i.e., alternating brief movements with brief pauses) could transform a heavy workload into a submaximal one that can be tolerated and sustained. The brief pauses that characterize intermittent locomotion permit at least partial recovery from prior activity. This research provided the foundation for the development of interval training and more recently for the re-evaluation of steady-state paradigms for comparative animal locomotion. In this paper I review key concepts underlying the performance of repeated activity. I provide examples from human athletics and training and comparative animal locomotion. To explore the limits of intermittent exercise performance, I examine the performance limits for continuous exercise and the rate and extent of the recovery of performance capacity following activity. While it is evident that altering locomotor behavior (i.e., moving intermittently) can alter the capacity of an animal to perform work, mathematical models of intermittent exercise could predict strategies (i.e., exercise intensity, exercise duration, and pause duration) that will increase performance limits for intermittent activity.