The main objective of this study was to assess the fitness level of players aged 13 to 18, determining possible differences with respect to training category (under-14, under-16 and under-18) and the specific position (goalkeepers, defenders, midfielders, forwards). 66 players were selected (with an age of 15.46\u2009\u00b1\u20091.83 years, a weight of 63.33\u2009\u00b1\u20099.51 kg, height of 171.44\u2009\u00b1\u20098.38 cm and prior competitive experience of 9.16\u2009\u00b1\u20091.93 years). We determined body composition (Inbody 720), hamstring flexibility (sit and reach test), countermovement jump and Abalakov test (MuscleLab 4000 testing system), and maximal oxygen consumption (multi-stage fitness test). Differences were found by specific position and training category in body composition and physical fitness (comparing under-14s with under-16s and under-18s) and differences were essentially found between the specific positions of under-16 defenders compared to their under-18 counterparts and between the specific position in the under-14 category versus the rest.<\/p>\n\n