Beyond the Pitch: Unveiling the Concave Hull as Soccer's Ecological Niche in Practice Design.

An ecological niche is a field in a landscape of affordances, rich in information inviting its inhabitants to develop functionality and effectiveness of their behavior. This idea means that, in sports like soccer, the playing area encapsulates an ecological niche, replete with affordances inviting collective and individual technical-tactical actions, contextualized with associated psychological and physical demands. To examine the co-adaptive relationships framing players' actions in their ecological niche, the present study employed a crossover design with repeated measures to compare the players' transactions within 11 vs. 11 training games across four different field dimensions (from official size to a small-sided game). Player transactions with the performance environment were analyzed across 40 game sequences, using 10Hz GPS positional data. Metrics such as convex hull dimensions, field occupancy, and proximity to opponents were derived. Repeated-measures ANOVA revealed significant differences between tendencies for forming synergies constrained by field dimensions scaling. When field size was reduced, the convex hull dimension significantly decreased. Additionally, relative field occupancy and distance to nearest opponent exhibited significant changes, especially when contrasted with performance transactions emerging on the official size field. These observations underline the essential functional relationship between the playing field dimension and emergent player actions. Such findings underscore the need for soccer coaches and training designers to integrate the specificity of field dimension scaling in training designs to represent competitive performance contexts. Data analytics deriving spatial constraint values from competitive matches may help researchers and practitioners improve task representativeness in practice and performance preparation, supporting the optimality of training niches in soccer.