Over the last few years, the technical and scientific community has increased exponentially their interest on warm-up in swimming, being aware of its importance for training and competition. Despite being a usual practice, literature is still scarce and unclear. There is a lot to know about the real effects of warm-up and how it could be designed with regard to the different components (such as the intensity, duration, and interval between warm-up and main task). This book, therefore, provides a set of new scientific evidences developed with the purpose of analysing the effects of warm-up on swimming performance in high-level swimmers. Different volumes, intensities and post warm-up recovery times were tested using cutting-edge technology to measure performance, biomechanical, physiological and psychophysiological responses of the swimmers. Several recommendations are done based on our recent research data and suggestions for future interventions are defined. Our findings should be useful to professionals and in sports, specifically in swimming (coaches, swimmers, researchers), and for anyone else who may be considering improving the knowledge on this particular topic.