This study aimed to examine position-specific physical demands among elite U19 football players competing in a 4-3-3 formation, using data collected via STATSports GPS technology. A total of 23 players from a top-tier Bosnian club, FK “Sarajevo”, were monitored during 26 official matches in the 2024/2025 season. Match data included total distance, distance in six speed zones, high-speed running (HSR), sprint distance, number of sprints, maximum speed, and acceleration/deceleration events. One-way ANOVA and Bonferroni post hoc analyses revealed significant positional differences across all performance metrics (p < 0.05). Central midfielders (CMs) covered the greatest total distance and distance per minute, while side defenders (SD) and forwards (FWs) recorded the highest values in sprint distance, HSR, and sprint frequency. Central defenders (CDs) consistently demonstrated the lowest outputs in high-speed and sprint metrics. These findings highlight the distinct physical profiles required for each playing position in a 4-3-3 system and provide practical insights for designing position-specific training and load management strategies in elite youth football.

Purpose. The aim of the study was to examine the effects of five weeks detraining period on body composition changes in elite professional Indonesian male soccer players. Material and methods. The body composition of 24 top-level male soccer players (age: 26.33 ± 4.06 years) competing in First League of Indonesia was measured before and after the 5-weeks detraining period. Body composition variables, including body mass, body fat percentage, fat-free mass, and total body water percentage, were measured using the bioelectrical impedance method. The results. The paired samples T-test showed significant changes in the means of body composition variables for body fat percentage, fat-free mass, and total body water percentage. Mean values for body fat percentage increased during the detraining period from 10.87 ± 2.47% to 11.98 ± 2.75% (10.3%). A decrease in mean values for fat-free mass (61.34 ± 5.74 kg to 59.80 ± 6.22; 2.49%) and total body water percentage (from 65.13 ± 1.84% to 64.40 ± 1.99%; 1.12%) was observed. No significant changes occurred in body mass (from 69.05 ± 8.07 kg to 69.05 ± 8.48 kg; 0.04%) from initial to final testing. Conclusions. Since there was a significant difference in body fat percentage, fat-free mass, and total body water percentage% before and after detraining period., it is suggested that 5 weeks of detraining period. for the professional soccer players may not be necessary, and the duration should be shortened to maintain body composition status.