The monitoring of young soccer players' training load using up-to-date devices is essential from the point of view of continuous improvement at high-quality soccer academies. In the present study, we used tests that are accepted and valid in soccer, which were performed frequently to find out more about improvement. Data measured in the U15–U19 age groups at the Illés Academy in Szombathely were analyzed during the research (N = 70). These data comprised (a) body parameters and performance

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... s: Body Mass, Height, Yo-Yo intermittent recovery test–level 1 (YYIR1), 30 m running, Functional Movement Screening (FMS), and Standing Long Jump (SLJ). (b) Locomotor parameters using the 6-week averages of Catapult OptimEye S5 standardized weekly reports of locomotor performance data (weeks 42–47, 2019): Total Time, Total Distance (m), Velocity Bands 4–6 Average Effort counts and distances, and Maximum Velocity. (c) Mechanical performance parameters: Total Player Load (TPL), high-intensity acceleration, high-intensity deceleration, Change of Direction (CoD) Left, High, CoD Right, High, and Explosive Effort (EE). The Illés Academy players did well in the motoric tests: YYIR1 (M = 2155, SD = 311), 30 m (M = 4.34, SD = 0.26), and SLJ (M = 2.28, SD = 0.18), and the different age groups underwent dynamic improvement. The young soccer players ran 19,552 m on average in their weekly training sessions (SD = 4562): players ran 568, 298, and 97 m in the moderate-, high-, and sprint-intensity zones (Velocity Band 4–5–6 Average Distance) (SD = 287, 148, and 67). The number of moderate-, high-, and sprint-intensity actions (Velocity Band 4–5–6 Average Effort Counts) was M = 58.32, 24.24, and 6.20 (SD = 24.41, 11.30, and 3.74). The athletes' maximum speed was M = 26.72 km/h (SD = 1.74). The differences between the age groups were justified statistically in each case. Moderate or more intensive correlations were not found between the different intensity of running and the body parameters. High-intensity correlations were found between the completed total distance and the number of moderate-intensity actions (r = 0.806, p < .001), and high correlations were found between the moderate-intensity and high-intensity running (r = 0.933, p < .001).