On 29 June 1958, Sweden played Brazil in the World Cup final in men’s football in Stockholm. Even though the Swedish team lost 5–2 the players were celebrated as heroes. However, the Swedish Football Association (SvFF) argued that players in Swedish clubs needed to train more and differently. What followed was a process of professionalization and scientization of Swedish coaching, a process that had begun a decade earlier in endurance sports. Soon, physiologists were involved with testing, evaluating and monitoring athletes, designing training setups, and even team selection. They used the latest scientific theories, technologies, and tests to make training and coaching less about experience and more about comparability and evidentiality. This ‘scientific turn’ in Swedish sports from the 1950s onwards was part of a larger rationalization of Swedish society in which science in general, particularly physiology, played a major role. It co-evolved with a growing participation by women and a reinterpretation of gender roles. We argue that, while traditionally based on experiential knowledge and personal experience, Swedish coaching went through a sportification process that made it more specialized, rationalized, and professionalized. In the end, it became an ideal to listen to what science says.