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  • Author: Dieter Deprez x
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Dieter Deprez, Joao Valente-dos-Santos, Manuel Coelho e Silva, Matthieu Lenoir, Renaat M. Philippaerts and Roel Vaeyens

Purpose:

To model the development of soccer-specific aerobic performance, assessed by the Yo-Yo Intermittent Recovery Test Level 1 in 162 elite pubertal soccer players, age 11–14 y at baseline.

Methods:

Longitudinal multilevel modeling analyses comprised predictors related to growth (chronological age, body size [height and weight] and composition [fat mass, fat-free mass]), and motor coordination [3 Körperkoordination Test für Kinder subtests: jumping sideways, moving sideways, backward balancing] and estimated biological-maturation groups (earliest [>percentile 33] and latest maturers [>percentile 66]).

Results:

The best-fitting model on soccer-specific aerobic performance could be expressed as –3639.76 + 369.86 × age + 21.38 × age2 + 9.12 × height – 29.04 × fat mass + 0.06 × backward balance. Maturity groups had a negligible effect on soccer-specific aerobic performance (–45.32 ± 66.28; P > .05).

Conclusion:

The current study showed that the development of aerobic performance in elite youth soccer is related to growth and muscularity and emphasized the importance of motor coordination in the talentidentification and -development process. Note that biological maturation was excluded from the model, which might endorse the homogeneity in estimated biological-maturation status in the current elite pubertal soccer sample.

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Job Fransen, Stephen Bush, Stephen Woodcock, Andrew Novak, Dieter Deprez, Adam D.G. Baxter-Jones, Roel Vaeyens and Matthieu Lenoir

Purpose: This study aimed to improve the prediction accuracy of age at peak height velocity (APHV) from anthropometric assessment using nonlinear models and a maturity ratio rather than a maturity offset. Methods: The dataset used to develop the original prediction equations was used to test a new prediction model, utilizing the maturity ratio and a polynomial prediction equation. This model was then applied to a sample of male youth academy soccer players (n = 1330) to validate the new model in youth athletes. Results: A new equation was developed to estimate APHV more accurately than the original model (new model: Akaike information criterion: −6062.1, R 2 = 90.82%; original model: Akaike information criterion = 3048.7, R 2 = 88.88%) within a general population of boys, particularly with relatively high/low APHVs. This study has also highlighted the successful application of the new model to estimate APHV using anthropometric variables in youth athletes, thereby supporting the use of this model in sports talent identification and development. Conclusion: This study argues that this newly developed equation should become standard practice for the estimation of maturity from anthropometric variables in boys from both a general and an athletic population.

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Job Fransen, Dieter Deprez, Johan Pion, Isabel B Tallir, Eva D’Hondt, Roel Vaeyens, Matthieu Lenoir and Renaat M. Philippaerts

The goal of this study was to investigate differences in physical fitness and sports participation over 2 years in children with relatively high, average, and low motor competence. Physical fitness and gross motor coordination of 501 children between 6–10 years were measured at baseline and baseline+2 years. The sample compromised 2 age cohorts: 6.00–7.99 and 8.00–9.99 years. An age and sex-specific motor quotient at baseline testing was used to subdivide these children into low (MQ < P33), average (P33 ≤ MQ < P66) and high (MQ ≥ P66) motor competence groups. Measures of sports participation were obtained through a physical activity questionnaire in 278 of the same children. Repeated Measures MANCOVA and two separate ANOVAs were used to analyze differences in changes in physical fitness and measures of sports participation respectively. Children with high motor competence scored better on physical fitness tests and participated in sports more often. Since physical fitness levels between groups changed similarly over time, low motor competent children might be at risk for being less physically fit throughout their life. Furthermore, since low motor competent children participate less in sports, they have fewer opportunities of developing motor abilities and physical fitness and this may further prevent them from catching up with their peers with an average or high motor competence.

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Job Fransen, Thomas W.J. Lovell, Kyle J.M. Bennett, Dieter Deprez, Frederik J.A. Deconinck, Matthieu Lenoir and Aaron J. Coutts

The aim of the current study was to examine the influence of restricted visual feedback using stroboscopic eyewear on the dribbling performance of youth soccer players. Three dribble test conditions were used in a within-subjects design to measure the effect of restricted visual feedback on soccer dribbling performance in 189 youth soccer players (age: 10–18 y) classified as fast, average or slow dribblers. The results showed that limiting visual feedback increased dribble test times across all abilities. Furthermore, the largest performance decrement between stroboscopic and full vision conditions was in fast dribblers, showing that fast dribblers were most affected by reduced visual information. This may be due to a greater dependency on visual feedback at increased speeds, which may limit the ability to maintain continuous control of the ball. These findings may have important implications for the development of soccer dribbling ability.