The method employed by coaches when designing small-sided soccer games has scarcely been studied by the scientific community. Therefore, the aim of this study was to develop a case study whereby one expert coach was interviewed and tasked with designing and justifying four different small-sided games for different physiological effects. Using these games, players were then tested and the real-time heart rate responses of the players were compared with the coach’s estimation. Thus, in the first instance a qualitative methodology and, secondly, a quantitative methodology, were developed to differentiate the games in terms of the effort produced and to compare the coach’s estimation with the actual real-time effects produced by the players’ efforts. It was thus possible to identify that, as predicted by the coach during the design of the games, the management of task constraints such as goals/targets and specific zones of action had statistical effects on the players’ efforts as measured by heart rate monitors. This case study revealed how the soccer-specific coach organizes his knowledge and experience to develop small-sided games and thus creates a line of future study to identify the fundamental decisions that differentiate novice and experienced coaches.
Key words: Coach Knowledge, Small-Sided Games, Soccer, Qualitative and Quantitative Methods.