The Ratio between Weekly Training and Match External Physical Loads in U17 Elite Youth Soccer Players: Implications for the Training Process

Background: Motor competence (MC) plays a critical role in shaping children’s physical activity, health-related fitness, and weight status. However, few studies have explored these interrelationships during middle childhood. Objectives: The current study aimed to examine the relationships between MC and physical activity (PA), health-related fitness (HRF), and weight status (WS) in children during middle childhood (9–10 years). Simultaneously, the study aimed to find possible differences in PA, HRF, and WS between children with different levels of MC. Methods: In this cross-sectional study, the TGMD-2 (MC), UNIFITTEST 6–60 (HRF), ActiGraph GT3X (PA), and anthropometry (WS) were administered to 86 children (59 boys, age range of 9–10 years and mean age of 10.1 ± 0.6 years). Results: A significant strong association was observed between MC and HRF (p < 0.01, Cramer‘s V = 0.42). Significant moderate associations were observed between MC and WS (p < 0.05, Cramer’s V = 0.34) and between MC and PA (p < 0.05, Cramer‘s V = 0.25). Children with high MC proficiency demonstrated significantly higher levels of HRF (p < 0.01; large ES) and PA (p < 0.05; moderate ES) and a healthier WS (p < 0.01; moderate ES) than those with low MC proficiency. Similarly, children with moderate MC proficiency outperformed children with low MC in terms of HRF and WS. Conclusions: The strong associations between MC and key health indicators such as PA, HRF, and WS suggest that movement proficiency in middle childhood should be viewed as a cornerstone of health promotion. Although no causal claims can be made, the results emphasize the practical importance of integrating targeted motor skill development—especially FMSs—into school-based physical education and extracurricular programs. Supporting MC at this age may be a decisive step toward fostering long-term engagement in physical activity and improving children’s overall health trajectories.

Purpose The present study revealed disparities between accelerations and decelerations across various continuous thresholds and different soccer academy age categories. Methods External loads from official matches were analyzed in U17 (72 matches; 376 observations; 62 players), U19 (72; 379; 73), and B team (59; 315; 58) across three consecutive seasons (2021–2024) using 10 Hz GPS technology. Averages were computed for each player/season from all official matches (> 90 min). Thresholds ranging from 1 to 2 m s⁻² to > 5 m s⁻² were employed to analyze the frequency of accelerations and decelerations. Linear mixed models with random effects for players and fixed effects for age category were used to compare accelerations and decelerations values. Results Statistical analysis showed a significantly higher frequency of accelerations than decelerations (p < 0.01) within the 2–3 m·s⁻² and 3–4 m·s⁻² thresholds. At higher thresholds (4–5 m·s⁻² and > 5 m·s⁻²), decelerations occurred significantly more often (p < 0.01). Moreover, the age category significantly affected most acceleration and deceleration metrics (p < 0.05, d > 0.5), with differences observed only between U17 and B team. The correlation between accelerations and decelerations decreased with increasing threshold intensity, ranging from strong (r = 0.78 at 1–2 m·s⁻²) to moderate (r = 0.45 at > 5 m·s⁻²). Conclusion The present outcomes underscore the prevalence of accelerative over decelerative actions at lower intensities but the opposite prevalence at high intensities. Differences between team categories indicate increasing demands on players transitioning to adult-level football. Additionally, caution is advised when relying solely on the average values for parameters that exceed specific thresholds.

Evidence regarding the influence of relative area per player (ApP), and playing position, on locomotor- and mechanical- external load during small-sided games in elite youth soccer players remains limited. This study aimed to examine associations between continuous ApP and external load during training-based small-sided games in elite U17 soccer players, and to explore whether playing position modified these responses. Twenty-two elite U17 soccer players (16.6 ± 0.47 years) were monitored during small-sided games, using mostly formats such as 4v4, 5v5, and 8v8-using observations derived from individual player responses across SSG bouts under three-game-density conditions. External load variables included total distance (TD); high-speed running distance (HSR); sprint distance (SPRINT); number of sprints (NSPRINTS); accelerations (ACC); decelerations (DEC); high metabolic load distance (HMLD); and, maximal-speed exposure (%MSPEED). Linear mixed-effects models were used to examine associations between continuous ApP and each external load variable, while accounting for repeated observations, including players and session-level clustering. Larger ApP values were positively associated with HSR, SPRINT, NSPRINTS, HMLD, and %MSPEED. In contrast, no significant associations were observed between ApP and TD; ACC; or DEC. No significant main effects of playing position or ApP × position interactions were identified. Supplementary player-level effect-size analyses indicated recurring exploratory positional patterns, particularly for high-speed and sprint-related variables. These findings suggest that ApP is a practical programming variable for scaling high-intensity locomotor and metabolically-demanding external load in elite youth soccer, whereas additional task constraints may be required to specifically target acceleration- and deceleration-based demands.

Purpose: The purpose of the study was to evaluate observer repeatability and inter-rater reproducibility of skeletal age assessment using the Tanner–Whitehouse 3 radius, ulna, and short bones (TW3-RUS) method on dual-energy X-ray absorptiometry (DXA) images, and to apply a complementary framework for evaluating observer-dependent measurement quality. Methods: Seventy-one elite male youth football players from the Czech Republic were assessed at two time points separated by one year. Skeletal age was estimated from DXA hand scans by an expert and a trained novice rater using the TW3-RUS method. Both observers repeated all assessments after two weeks. Measurement quality was evaluated using the intraclass correlation coefficient ICC(2,1), standard error of measurement (SEM), Bland–Altman analysis with proportional bias testing, bootstrap confidence intervals, and a predefined ±0.5-year decision threshold. Results: Observer repeatability and inter-rater reproducibility were excellent at both annual assessments (ICC = 0.965–0.999). The expert maintained consistently low measurement error (SEM < 1 month), whereas the trained novice reduced SEM from 3.7 to 2.5 months after one year of practical experience. Bland–Altman analyses demonstrated only minor systematic differences and no meaningful proportional bias in the overall sample, whereas only a minority of observations exceeded the predefined decision threshold. Conclusions: DXA-derived TW3-RUS skeletal age assessment provides excellent repeatability and reproducibility under standardised conditions. Observer experience primarily improves measurement precision rather than ranking consistency. The principal contribution of this study is a complementary validation framework integrating repeatability, reproducibility, precision, agreement, and decision-oriented analyses, providing a methodological basis for evaluating observer-dependent assessment methods in sport science.

The purpose of the study was to compare training-to-match load ratios between U17 and U19 soccer players, focusing on effective training time, external load, and intensity. Two youth academy teams were assessed: U19 (n = 22; 6 weeks; 59 training weeks) and U17 (n = 21; 11 weeks; 112 training weeks). The external load was tracked using a 10-Hz GPS and included total distance (TD), high-speed running (HSR), sprint distance (SPRm), sprint entries (SPRn), accelerations, decelerations, and impacts (>5 g). Total and effective training time were recorded separately to calculate relative intensities. Generalized linear mixed model was used to compare U17, U19, and U19 excluding one session (U19 MD-2) to ensure equivalent weekly structure. U17 players showed significantly higher training efficiency (ET%: 71.0 ± 7.3%) than U19 players (68.5 ± 4.0%). U19 players demonstrated higher training-to-match load ratios, particularly in HSR (U19: 1.5 ± 0.4; U19 MD-2: 1.2 ± 0.4; U17: 1.0 ± 0.4; p < 0.01) and SPRm (U19: 2.0 ± 1.0; U19 MD-2: 1.8 ± 0.9; U17: 1.0 ± 0.8; p < 0.01). U17 players struggled to replicate match intensities in sprinting and high-speed running. Differences were also observed in acceleration and deceleration profiles. Effect sizes ranged from moderate to large across sprint and HSR metrics. Training-to-match load ratios varied substantially between U17 and U19 players. While U19 players exceeded match intensities in most metrics, U17 players fell short, especially of sprinting demands. These findings support the use of structured high-intensity training and individualized load management to optimize development and prepare youth players for professional demands.