We compared the physical and physiological responses of young soccer players of different ages U13 (Under 13 years), U15, and U17 and competitive levels (elite and sub-elite) during fixed-pitch size small sided games (SSGs) performed under different formats. In a cross-sectional design, seventy-two male players (12 players in each group) performed 3-a-side and 4-a-side SSGs with a fixed-pitch size (40×20 m). Th...