Jorge Mota, Rute Santos, Manuel João Coelho-e-Silva, Armando M. Raimundo and Luís B. Sardinha
Gillian K. Myburgh, Sean P. Cumming, Manuel Coelho E. Silva, Karl Cooke and Robert M. Malina
To evaluate relationships among skeletal maturity, body size, and functional capacities of elite junior tennis players.
Participants were 88 elite British Junior tennis players (44 male; 44 female), 8–16 years of age (12.4 } 1.9 years). Skeletal age estimated maturty. Anthropometry, grip strength, countermovement jump, squat jump, forehand agility, backhand agility, Yo-Yo, 5-m, 10-m and 20-m sprints were measured. Comparative analysis for each sex was performed, relating advanced maturers (Male: 15; Female: 29) to a combination of on-time and late maturers (Male: 29; Female: 31). ANCOVAs were used to determine absolute differences between male and female players and between the 2 maturity subgroups, with chronological age as the covariate.
Advanced maturity afforded male players advantages in absolute measures of grip strength, speed, upper and lower body power but not in acceleration, agility or aerobic endurance. Male players were significantly taller than females in the U13-U16 age group. Advanced maturity in female players afforded advantages in absolute measures of grip strength, agility and overhead power, but not in backhand agility, aerobic endurance or squat jump power.
It is important that talent identification protocols consider the maturity of youth athletes to more satisfactorily address athletic potential rather than transient physical capabilities.
Jorge Mota, Manuel João Coelho-e-Silva, Armando M. Raimundo and Luís B. Sardinha
This article describes the procedures and development of the first Portuguese Report Card on Physical Activity in Children and Adolescents.
Comprehensive searches for data related to indicators of physical activity (PA) were completed by a committee of physical activity and sports specialists. Grades were assigned to each indicator consistent with the process and methodology outlined by the Active Healthy Kids Canada Report Card model.
Nine indicators of PA were graded. The following grades were assigned: Overall Physical Activity Levels, D; Organized Sport Participation, B; Active Play, D; Active Transportation, C; Sedentary Behaviors, D; Family and Peers, C; Schools, B; Community and the Built Environment, D; and Government, C.
Portuguese children and adolescents do not reach sufficient physical activity levels and spend larger amounts of time spent in sedentary behaviors compared with recommendations. Effective policies of PA promotion and implementation are needed in different domains of young people’s daily lives.
Robert M. Malina, Sean P. Cumming and Manuel J. Coelho e Silva
“Gaps in Our Knowledge” are discussed in the context of the need to integrate biological and behavioral factors in a biocultural approach to physical activity and movement proficiency. Specific issues considered include outdoor play, organized and informal activity, biological maturation, tracking of activity, development of movement proficiency, and individual differences. Studies considered are largely based on youth in economically better-off, developed countries in the western culture context. There is a need to extend studies of physical activity and movement proficiency to different cultural contexts.
Humberto M. Carvalho, Manuel J. Coelho-e-Silva, Joey C. Eisenmann and Robert M. Malina
Relationships among chronological age (CA), maturation, training experience, and body dimensions with peak oxygen uptake (VO2max) were considered in male basketball players 14–16 y of age. Data for all players included maturity status estimated as percentage of predicted adult height attained at the time of the study (Khamis-Roche protocol), years of training, body dimensions, and VO2max (incremental maximal test on a treadmill). Proportional allometric models derived from stepwise regressions were used to incorporate either CA or maturity status and to incorporate years of formal training in basketball. Estimates for size exponents (95% CI) from the separate allometric models for VO2max were height 2.16 (1.23–3.09), body mass 0.65 (0.37–0.93), and fat-free mass 0.73 (0.46–1.02). Body dimensions explained 39% to 44% of variance. The independent variables in the proportional allometric models explained 47% to 60% of variance in VO2max. Estimated maturity status (11–16% of explained variance) and training experience (7–11% of explained variance) were significant predictors with either body mass or estimated fat-free mass (P ≤ .01) but not with height. Biological maturity status and training experience in basketball had a significant contribution to VO2max via body mass and fat-free fat mass and also had an independent positive relation with aerobic performance. The results highlight the importance of considering variation associated with biological maturation in aerobic performance of late-adolescent boys.
Ricardo Rebelo-Gonçalves, Manuel João Coelho-e-Silva, Vítor Severino, Antonio Tessitore and António José Barata Figueiredo
Studies focused on position-related characteristics of young soccer players often ignore the goalkeepers. The aim of this study was to examine the effect of playing position on anthropometry, physiological attributes, soccer skills, and goal orientation across adolescence. One hundred forty-five soccer players age 11–19 y were assessed in training experience, body size, maturation, physiological parameters, soccer skills, and goal orientation. Factorial ANOVA was used to test the effect of age group, playing position, and respective interaction terms, while analysis of variance was used to compare goalkeepers vs outfielders in middle (under 13 [U-13] and U-15) and late (U-17 and U-19) adolescence. Discriminant analysis was used to identify the variables that contributed to explaining playing positions. Age group was a consistent source of variation for all variables except task and ego orientations. Fat mass, agility, endurance, dribbling speed, shooting accuracy, and passing were affected by the gradient derived from the classification between goalkeepers and outfielders. It was possible to correctly classify the playing position based on fat-free mass and 3 manipulative skills in younger players and on 4 skills in U-17 and U-19 soccer players. Future research should include longitudinal information to improve our understanding of the factors that contribute to distinguish goalkeepers from outfielders.
António J. Figueiredo, Manuel J. Coelho e Silva, Sean P. Cumming and Robert M. Malina
The purpose of the study was to compare the anthropometric, functional and sport-specific skill characteristics and goal orientations of male youth soccer players at the extremes of height and skeletal maturity in two competitive age groups, 11–12 and 13–14 years. The shortest and tallest players, and least and most skeletally mature players (n = 8 per group) within each age group were compared on chronological age; skeletal age (Fels method); pubertal status (pubic hair); size, proportions and adiposity; four functional capacities; four soccer-specific skills; and task and ego orientation. The tallest players were older chronologically, advanced in maturity (skeletal, pubertal) and heavier, and had relatively longer legs than the shortest players in each age group. At 11–12 years, the most mature players were chronologically younger but advanced in pubertal status, taller and heavier with more adiposity. At 13–14 years, the most mature players were taller, heavier and advanced in pubertal status but did not differ in chronological age compared with the least mature players. Players at the extremes of height and skeletal maturity differed in speed and power (tallest > shortest; most mature > lest mature), but did not differ consistently in aerobic endurance and in soccer-specific skills. Results suggested that size and strength discrepancies among youth players were not a major advantage or disadvantage to performance. By inference, coaches and sport administrators may need to provide opportunities for or perhaps protect smaller, skilled players during the adolescent years.
Susana C. A. Póvoas, Carlo Castagna, José Manuel da Costa Soares, Pedro Silva, Manuel Coelho-e-Silva, Fernando Matos and Peter Krustrup
The reliability and construct validity of three age-adapted-intensity Yo-Yo tests were evaluated in untrained (n = 67) vs. soccer-trained (n = 65) 9- to 16-year-old schoolgirls.
Tests were performed 7 days apart for reliability (9- to 11-year-old: Yo-Yo intermittent recovery level 1 children’s test; 12- to 13-yearold: Yo-Yo intermittent endurance level 1; and 14- to 16-year-old: Yo-Yo intermittent endurance level 2).
Yo-Yo distance covered was 40% (776 ± 324 vs. 556 ± 156 m), 85% (1252 ± 484 vs. 675 ± 252 m) and 138% (674 ± 336 vs. 283 ± 66 m) greater (p ≤ .010) for the soccer-trained than for the untrained girls aged 9–11, 12–13 and 14–16 years, respectively. Typical errors of measurement for Yo-Yo distance covered, expressed as a percentage of the coefficient of variation (confidence limits), were 10.1% (8.1–13.7%), 11.0% (8.6–15.4%) and 11.6% (9.2–16.1%) for soccer players, and 11.5% (9.1–15.8%), 14.1% (11.0–19.8%) and 10.6% (8.5–14.2%) for untrained girls, aged 9–11, 12–13 and 14–16, respectively. Intraclass correlation coefficient values for test-retest were excellent (0.795–0.973) in both groups. No significant differences were observed in relative exercise peak heart rate (%HRpeak) between groups during test and retest.
The Yo-Yo tests are reliable for determining intermittent-exercise capacity and %HRpeak for soccer players and untrained 9- to 16-year-old girls. They also possess construct validity with better performances for soccer players compared with untrained age-matched girls, despite similar %HRpeak.
Joric B. Vandendriessche, Barbara Vandorpe, Manuel J. Coelho-e-Silva, Roel Vaeyens, Matthieu Lenoir, Johan Lefevre and Renaat M. Philippaerts
Discussions of growth and motor performance of children are often set in the context of physical fitness. Although there is a clear theoretical concept or definition of fitness comprising motor coordination, the latter is not systematically considered. This study determined to what extent the variance in motor coordination might be explained by morphological and fitness characteristics. To postulate understanding of this association during childhood, 613 boys aged 7–11 years completed the morphological measurements, the Körperkoordinationstest für Kinder (KTK) and different fitness tests. The results demonstrated a substantial interrelationship among morphology, fitness and motor coordination in elementary school boys. The magnitude of explained variance and the loadings of the canonical correlation between the several constructs are strongly pronounced during childhood indicating that these constructs should be well considered given their contribution to a child’s general development.
Dieter Deprez, Joao Valente-dos-Santos, Manuel Coelho e Silva, Matthieu Lenoir, Renaat M. Philippaerts and Roel Vaeyens
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.
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]).
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).
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.