Relationship Between Body Size and Skeletal Age with Muscle Damage in Young Soccer Players.

This study verified the relationship between body size and skeletal age (SA) with the behavior of blood markers of muscle damage and delayed onset muscle soreness (DOMS) after a soccer match in the U-13 and U-15 categories. The sample consisted of 28 soccer players in the U-13 and 16 in the U-15 categories. Creatine kinase (CK), lactate dehydrogenase (LDH), and DOMS were evaluated up to 72 h after the match. Muscle damage was elevated at 0 h in U-13, and from 0 h to 24 h in U-15. DOMS increased from 0 h to 72 h in U-13 and from 0 h to 48 h in U-15. Significant associations of SA and fat-free mass (FFM) with muscle damage markers and DOMS were observed only in U-13, specifically at time 0 h, when SA explained 56% of CK and 48% of DOMS and FFM explained 48% of DOMS. We concluded that in the U-13 category, higher SA is significantly associated with muscle damage markers, and increase in FFM is associated with muscle damage markers and DOMS. Furthermore, U-13 players need 24 h to recover pre-match muscle damage markers and more than 72 h to recover DOMS. In contrast, the U-15 category needs 48 h to recover muscle damage markers and 72 h to recover DOMS.

Body size, maturation and motor performance in young soccer players: relationship of technical actions in small-sided games.

The objective of this study was to investigate the relative contributions of body size, skeletal age, and motor performance variables with technical actions through an ecological model during small-sided soccer games, and the interaction of biological maturation with technical and motor performance in young players. In this cross-sectional study, eighty-two young players (14.4 ± 1.1 years), belonging to state-level soccer teams and divided by category (U-13 and U-15), were included. Players having an injury in the evaluation period were not included in the study. Measurements of body size, skeletal age (SA), motor tests, and technical actions in small-sided games (SSG) were performed (3 × 3 plus goalkeeper) in two periods (halves) of four minutes. Differences between age groups were found for SA (ES = -2.36), chronological age (ES = -3.89), body mass (ES = -2.09), height (ES = -1.90), and fat-free mass (ES = -2.09). Positive associations were found between body size (R = 0.43 to R = 0.48) and manipulation (R = 0.50 to R = 0.52) indicators and numbers of technical actions (CB and SS), except for stature with LB (R = -0.42) in the U-13 age group. In the U-15 category, skeletal age (R = -0.29 to R = -0.30) and body mass (R = -0.28 to R = -0.29) were negatively associated with the number of technical actions (RB, NB, LB, and OB) (P > 0.05) and positively with the balance with LB (R = 0.26). In conclusion, body size, SA, and motor performance influenced technical actions in SSG differentially in each category. U-13 heavier players and those with a better motor performance presented higher involvement due to the higher.

Maturity-associated variation in the body size, physical fitness, technical efficiency, and network-based centrality measures in young soccer players.

This study aimed to observe the relationships between the maturity status on the network-based centrality measures of young athletes in small-sided soccer games (SSG). The study included 81 male players (14.4 ± 1.1 years). Measurements included height, sitting height, body mass, and bone age (TW3 method). The applied protocols were the following: Countermovement Jump (CMJ), Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1), Repeated Sprints Ability (RSA), observational analysis of techniques, and interactions performed by players in SSG. The relationship between the set of evaluated variables within each maturity status was obtained from the correlational analysis of networks (P < 0.05). The maturity status explained a significant portion of the variance in body mass (η2 = 0.37), height (η2 = 0.30), sitting height (η2 = 0.30), and performance on the YYIRT1 (η2 = 0.08), CMJ (η2 = 0.14), and RSA (η2 = 0.13). No effect of maturity status on network-based centrality measures of young athletes was identified (P > 0.05). For the late maturity group, there was a correlation between the degree of centrality and physical growth indicators (rmean = 0.88). For players with maturation "on time", physical growth indicators relate to the degree of prestige (rmean = 0.36). It is concluded that body size and bone age impact how late and on-time maturity groups interact within the match.

Using Social Network Analysis to Study Relationships Between Young Soccer Players' Bone Age, Body Size, and the Centrality of Their Pass Interactions.

Prior research has suggested relevance to anthropometric variance of youth athletes at various stages of their maturation, and prior studies of youth players' soccer skills have failed to consider their interdependent interactions during play. Accordingly, to address both of these separate research omissions, we aimed in this study to analyze the relationships between young (U-13 and U-15 groups) soccer players' bone age and body size indicators and centrality measures of their pass interactions during small sided games. We included young 81 athletes (M age = 14.4, SD = 1.1 years) from whom we took anthropometric measurements of body mass, height, and trunk-cephalic height and obtained their bone age using the Tanner-Whitehouse 3 classification method. We also filmed small-sided games in the goal keeper/three player (GK3-3GK) format to analyze the centrality of their passing actions on the following measures: degree of centrality, closeness of centrality, degree of prestige, and proximity of prestige. There were no group differences in the prominence of passing actions across these three measures (tmean = -3.13; p > .05). Canonical correlations of these relationships were significant only in the U-13 group, in which centrality in passing actions was related to body size (r = 0.71; R2 = 0.21; ʌ = 0.28; p = .03). U-13 players who were physically larger and who presented higher bone age showed centralized main passing actions.

Combined effect of game position and body size on network-based centrality measures performed by young soccer players in small-sided games.

This study verified the effects of body size and game position on interactions performed by young soccer players in small-sided games (SSG). The sample consisted of 81 Brazilian soccer players (14.4 ± 1.1 years of age). Height, body mass, and trunk-cephalic height were measured. SSG was applied in the GK + 3v3 + GK format, and Social Network Analyses were carried out through filming the games to obtain the following prominence indicators: degree centrality, closeness centrality, degree prestige, and proximity prestige, in addition to network intensity and number of goals scored. Factorial ANCOVA (bone age as covariate) was used to test the effects of game position, body size, and respective interaction on centrality measurements (p < 0.05). Similarity between game positions in body size indicators (p > 0.05) was observed. The game position affected degree centrality (p = 0.01, η 2 = 0.16), closeness centrality (p = 0.01, η 2 = 0.11), and network intensity (p = 0.02, η 2 = 0.09), in which midfielders presented the highest network prominence values when compared to defenders and forwards. In conclusion, midfielders are players with high interaction patterns in the main offensive plays, which behavior is independent of body size.

Age- and size-corrected kicking speed and accuracy in elite junior soccer players.

Kicking powerfully and accurately is essential in soccer, and players who kick proficiently with both feet are highly sought after. Assessing performance in youth players is often confounded by more physically developed players outperforming their smaller peers. To alleviate such bias, we present a testing protocol and normative data developed with an elite Brazilian soccer academy that controls for players' age and size to assess kick performance with both feet. We measured kick speed and kick accuracy of 178 players and recorded their age (10-20 years), height, and mass. Combining age, height, and mass into an age and size index (ASI), we developed equations describing the relationship between ASI and performance. To determine the underlying predictors of performance, we also measured sprint ability and soccer-specific motor control of each foot with ball dribbling tasks. Kicking speed with the dominant foot was predicted by ASI, sprint speed, and motor control of the nondominant foot, while kicking speed with the nondominant foot was predicted by ASI and motor control of the nondominant foot. Kick accuracy with each foot was predicted by ASI and motor control of the corresponding foot. To improve kicking performance, we suggest training programs focus on motor control.

Relative age effect in brazilian handball selections / Efeito relativo da idade nas seleções brasileiras de handebol

ABSTRACT The aim of this study was to evaluate the relative age effect (RAE) in Brazilian male handball teams who competed in the world championships in the U-19, U-21, and adult categories. The sample was composed by 160 male handball players, 47 players being on U-19 category, 48 on U-21, and 65 on Adult category. The chronological age, body mass, height, and game position of each athlete were obtained on the International Federation of Handball website. The adopted significance level was of 5%. RAE was observed in all the three following categories U-19 (X2=21.511, P<0.01), U-21 (X2=15.894, P=0.01) and Adults (X2=35.123, P<0.01). Moreover, no RAE was found in re-selection process by sequential category (P= 0.63, U-19 to U-21; P= 0.46, U-21 to Adult). The RAE is found in Brazilian male handball national teams. However, this effect was not found in re-selection process, thus, players have great influence of RAE in U-19 and this remains through subsequent categories.

RESUMO O objetivo do presente estudo foi avaliar o efeito relativo da idade (ERI) nas seleções Brasileira de handebol que competiram nos campeonatos mundiais das categorias Sub-19, Sub-21 e Adulta. A amostra foi composta por 160 jogadores de handebol do sexo masculino, sendo 47 pertencentes a categoria Sub-19, 48 a Sub-21 e 65 a Adulta. A idade cronológica, massa corporal, estatura e posição de jogo de cada atleta foram obtidas no site oficial da Federação Internacional de Handebol. O nível de significância adotado foi de 5%. ERI foi observado em todas as três seguintes categorias Sub-19 (X2=21.511, P<0.01), Sub-21 (X2=15.894, P=0.01) e adulta (X2=35.123, P<0.01). Além disso, não foi encontrado ERI no processo de re-seleção pela categoria sequencial (P= 0.63, Sub-19 para Sub-21; P=0.46, Sub-21 para Adulta). O ERI foi encontrado nas seleções brasileiras de handebol. Contudo, este efeito não foi encontrado no processo de re-seleção, assim, os jogadores sofrem grande influência do ERI na categoria Sub-19 e isto permanece durante as categorias subsequentes até a equipe adulta.