What goes on in the body and mind of an endurance athlete at the limits of performance? How do they relate to the world around and prepare for the task ahead? Offering a refreshing perspective on training in the cross-lighting of aesthetic and athletic processes, this book focuses on the learning, mastery and creative adaptation of technique in performance. From traditional and physical actors to runners, boxers and other sports practitioners, it is about performers: their bodies, trainings and experiences. It interrogates what it means to prepare and train as a performer in the early 21st century. Writing from extensive experience in physical theatre and long-distance running, the author combines insights from both disciplines along with theatre history, sports science and perspectives like embodied cognition and affective science. From the kind of thoughts that go through the mind of an actor or a runner, to the economy and aesthetic of their movement and to how they feel about it, this book sheds light on the performing body and its capacities for action. Topics covered include attentional focus and distraction, affordances and equipment, 'choking' and stage fright, physiological regulation and effort perception, pacing and play, optimal flow and creative improvisation, and intentionality and automaticity in expert performance. The volume presents an informative and thought-provoking account accessible to readers interested in theatre, dance, performance, running, athletics, and sport.