The performance of a football team is strongly influenced by the breadth of tactical action knowledge (e.g., Praça, Pérez morales, Bredt & al., 2017). Possessing a significant knowledge base helps players memorize game plans and systems for on-field application. It also contributes to analyzing and anticipating the opposing team's moves during different phases of play: structured attacks, zone defense, counter attacks, defensive drops, and transitions (e.g., Zoudji, Thon & Debû, 2010). However, to date, no studies have addressed the question of the breadth of tactical action knowledge that players use during training stages. This study aims to assess the breadth of tactical action knowledge that elite young footballers use during different training stages: U-15 and U-18 categories. A question guides this work: (1) What is the breadth of tactical actions used by each age category?