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Background: The assessment of biological maturity status plays an important role in talent identification and development programs., Aim: To compare age at predicted adult height and BAUS skeletal age as indicators of biological maturity status in youth soccer players using a construct-validity approach., Subjects and Methods: Participants were 114 players from the U12 to U17 age groups of a professional youth soccer academy. Maturity status was determined via percentage of predicted adult height based upon the Khamis-Roche method (somatic maturity) and assessed via the SonicBone BAUS TM system (skeletal maturity). Convergent and known-groups validity were evaluated between maturity assessment methods and by comparing maturity-related selection biases across age groups., Results: Although maturity status indicators were largely interrelated (r = .94, 95%CL 0.91-0.96), concordance (κ = 0.31 to 0.39) and Spearman's rank-order correlations (ρ = 0.45-0.52) of classification methods were moderate. A selection bias towards early maturing players emerged in the U14 age group which remained relatively consistent through to the U17 age group., Conclusions: Results confirm the construct-validity of both methods to assess biological maturity status although further validation relative to established indicators of biological maturity is needed. Furthermore, caution is also warranted when interpreting maturity status classification methods interchangeably given the poor concordance between classification methods.

Background: During adolescence, deselection from sport occurs during team try-outs when month of birth, stage of growth and maturation may influence selection., Aim: The purpose of this study was to identify differences in growth and maturity related factors between those selected and deselected in youth sports teams and identify short-term associations with continued participation., Subjects and Methods: Eight hundred and seventy participants, aged 11-17 years, were recruited from six sports try-outs in Saskatchewan, Canada: baseball, basketball, football, hockey, soccer and volleyball. Two hundred and forty-four of the initial 870 (28%) returned for follow-up at 36 months. Chronological (years from birth), biological (years from age at peak height velocity (APHV)) and relative (month of birth as it relates to the selection band) ages were calculated from measures of date of birth, date of test, height, sitting height and weight. Parental heights were measured or recalled and participant's adult height predicted. Reference standards were used to calculate z -scores. Sports participation was self-reported at try-outs and at 36-month follow-up., Results: There was an over-representation of players across all sports born in the first and second quartiles of the selection bands ( p  < 0.05), whether they were selected or deselected. z -scores for predicted adult height ranged from 0.1 (1.1) to 1.8 (1.2) and were significantly different between sports ( p  < 0.05). Height and APHV differences ( p  < 0.05) were found between selected and deselected male participants. In females only weight differed between selected and deselected female hockey players ( p  < 0.05); no further differences were found between selected and deselected female participants. Four per cent of deselected athletes exited sports participation and 68% of deselected athletes remained in the same sport at 36 months, compared with 84% of selected athletes who remained in the same sport., Conclusions: It was found that youth who attended sports team's try-outs were more likely to be born early in the selection year, be tall for their age, and in some sports early maturers. The majority of both the selected and deselected participants continued to participate in sport 36 months after try-outs, with the majority continuing to participate in their try-out sport.

Context: Bio-banding is the process of grouping players by their maturational status rather than chronological age. It is designed to limit the impact of maturational timing on talent identification and development and expose early and late maturing players to new learning experiences and challenges. A common criticism of bio-banding is that it does not consider age related differences in psychosocial and behaviour development., Objective: The purpose of this case study is to describe how theory and research pertaining to the design and delivery of mixed-aged classrooms can be used to prepare early and late maturing players for bio-banding and optimise the benefits of this practice., Method: After placing the players in their bio-banded groups, one Elite Premier League Academy provided bespoke group psychology sessions for early and late maturing players for six weeks., Results: Providing bespoke psychology sessions for players maturation age allows for the cognitive processes of both early and late maturity status to work within the zone of proximal development., Conclusion: Pedagogical practice associated with mixed age classrooms can be used in bio-banded contexts to benefit both early and late maturing players. Delivering psychological sessions alongside bio-banding permits learning and development to both ends of the maturity spectrum.

Background: The influence of maturity-status on athletic performance is reasonably well-documented. Methodological and practical issues of assessment and lack of longitudinal data have impacted the success of various models., Aim: To develop age- and sex-specific developmental curves for sprint acceleration in elite youth tennis players and to address variation in performance relative to chronological and biological age., Subjects and Methods: Measures of acceleration were available for 3120 elite youth tennis players aged 8-15 years attending National and Regional Talent Identification days. Variation in acceleration by chronological and estimated biological ages was evaluated in corresponding data for an independent sample of elite youth players 8.9 to 15.1 years of age., Results: Acceleration varied as a function of chronological and biological age relative to developmental curves. Early maturing males and females had significantly poorer performances when acceleration was considered relative to biological age. Significant discrepancy in percentiles relative to biological versus chronological ages was also evident between early and late maturing players of each sex., Conclusion: Evaluating performance relative to developmental curves and maturity status may be a practical means of monitoring long-term athlete development in tennis.

Purpose: To estimate the biological maturity status of youth football players 9-14 yr old using a noninvasive method and to compare the body size of players of contrasting status., Methods: Subjects were members of youth football teams in two central Michigan communities. Height and weight were measured on 653 boys 8.7-14.6 yr. Heights of biological parents of 582 boys were reported and subsequently adjusted for overestimation. Decimal age, height, and weight of the player and midparent height were used to predict mature (adult) height for the boy. Current height of each player was expressed as a percentage of his predicted mature height to provide an estimate of biological maturity status. Percentage of predicted mature height of each boy was expressed as a z-score to classify players into maturity groups. ANCOVA, controlling for age, was used to compare body size in contrasting maturity groups., Results: Mean percentages of predicted mature height of the players matched those of longitudinal reference samples, but there was a trend for higher percentages among older players, suggesting advanced maturation. Overall, 405 boys were classified as on time/average in maturity status (69.6% [95%CI 65.7-73.3]), 154 were classified as early/advanced (25.5% [95%CI 23.0-30.3]), and only 23 were classified as late/delayed (3.9% [95%CI 2.6-6.0]). The gradient for height, weight, and BMI was as follows: early > on time > late, and differences were greater for weight and the BMI than for height., Conclusion: Percentage of predicted mature height attained at a given age appears to be a reasonable indicator of maturity status. The method needs to be validated with other more direct indicators (skeletal age, sexual maturation) and applied to other samples.

Objective: To characterize the growth status of participants in community-sponsored youth football programs and to estimate rates of growth in height and weight., Design: Mixed-longitudinal over 2 seasons., Setting: Two communities in central Michigan., Participants: Members of 33 youth football teams in 2 central Michigan communities in the 2000 and 2001 seasons (Mid-Michigan PONY Football League)., Methods: Height and weight of all participants were measured prior to each season, 327 in 2000 and 326 in 2001 (n = 653). The body mass index (kg/m) was calculated. Heights and weights did not differ from season to season and between the communities; the data were pooled and treated cross-sectionally. Increments of growth in height and weight were estimated for 166 boys with 2 measurements approximately 1 year apart to provide an estimate of growth rate., Main Outcome Measure: Growth status (size-attained) of youth football players relative to reference data (CDC) for American boys and estimated growth rate relative to reference values from 2 longitudinal studies of American boys., Results: Median heights of youth football players approximate the 75th percentiles, while median weights approximate the 75th percentiles through 11 years and then drift toward the 90th percentiles of the reference. Median body mass indexes of youth football players fluctuate about the 85th percentiles of the reference. Estimated growth rates in height approximate the reference and may suggest earlier maturation, while estimated growth rates in weight exceed the reference., Conclusion: Youth football players are taller and especially heavier than reference values for American boys. Estimated rates of growth in height approximate medians for American boys and suggest earlier maturation. Estimated rates of growth in weight exceed those of the reference and may place many youth football players at risk for overweight/obesity, which in turn may be a risk factor for injury.

"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. [ABSTRACT FROM AUTHOR]

Baseline characteristics of 31 healthy male U15 soccer players who were classified as select or non-select at the end of the season were compared. Players were 14.4 ± 0.54 years (13.6-15.3 years) at baseline; characteristics included body size, proportions and composition, estimated maturity status, several functional capacities, and coach classifications of potential in the sport. Decisions regarding selection or non- selection were made about two months after baseline. Select and non-select U15 soccer players differed significantly in estimated maturity status, body size, proportions and estimated muscle mass, functional tests related to speed, power and strength, and coach evaluation of potential, specifically tactical skills on offense and skills associated with creativity and decision making. When age and biological maturity status were statistically controlled, select and non-select players differed significantly only on the vertical jump, grip strength, and coach ratings of tactical skills on offense and of creativity and decision making. Results of stepwise discriminant analysis highlighted the importance of coach evaluation of tactical skills associated with offense, and of power and strength in distinguishing select from non-select players. The results highlight the advantages of advanced biological maturity status among adolescent male soccer players and also the importance of coach perceptions of talent. The latter implies a need for further study of the basis of coach perceptions, specifically how they are influenced by and perhaps interact with player characteristics at different ages, and how the perceptions influence playing time and player behaviors and interactions. [ABSTRACT FROM AUTHOR]

Equations predicting age at peak height velocity (APHV) are often used to assess somatic maturity and to adjust training load accordingly. However, information on the intra-individual accuracy of APHV in youth athletes is not available. The purpose of this study is to assess the accuracy of predication equations for the estimation of APHV in individual youth male football players. Body dimensions were measured at least every three months in 17 elite youth male football players (11.9 ± 0.8 years at baseline) from the 2008–2009 through the 2011–2012 seasons. APHV was predicted at each observation with four suggested equations. Predicted APHV was compared to the player's observed APHV using one-sample-t-tests and equivalence-tests. Longitudinal stability was assessed by comparing the linear coefficient of the deviation to zero. Predicted APHV was equivalent to the observed APHV in none of the players. A difference with a large effect size (Cohen's d > 0.8) was noted in 87% of the predictions. Moreover, predictions were not stable over time in 71% of the cases. None of the evaluated prediction equations is accurate for estimating APHV in individual players nor are predictions stable over time, which limits their utility for adjusting training programmes. [ABSTRACT FROM AUTHOR]

Purpose: To compare characteristics of club level male soccer players 11 and 13 years of age, and to evaluate playing status in soccer two and 10 years after baseline by birth quarter (BQ). Methods: Youth players 11 (n = 62, born 1992, observed December 2003) and 13 (n = 50, born 1990, observed April 2004) years were grouped by BQ. Baseline data included stature, weight, maturity status, functional capacities, soccer skills, goal orientation, and coach evaluation of potential. Playing status in soccer in 2006 and 2014 was also available. Baseline characteristics and subsequent playing status were compared by BQ. Results: Baseline characteristics did not differ by BQ except for age and percentage of predicted adult height. Though not significant, coaches tended to rate players in BQ1as higher in potential. For those competing in soccer as adults, BQ2 (4), BQ3 (5) and BQ4 (2) were represented among players11 years, and BQ1 (3), BQ2 (2), BQ3 (1) and BQ4 (4) among players 13 years. Conclusion: Although limited to small numbers, differences among players by BQ were inconsistent. The results indicate a need to extend potential explanations of the RAE to include behavioral variables, coaches, training environment, and perhaps the culture of the sport. [ABSTRACT FROM AUTHOR]

The pubertal transition can present an interesting paradox for the young dancer, with growth and maturation leading to improvements in some areas such as strength and power and detriment to others, such as flexibility and co-ordination. These challenges highlight the need to consider the interactions among biological, psychological and sociocultural factors during the pubertal transition in the context of the ballet environment. Awareness of these potential interactions will likely provide insights as to why some dancers successfully adapt to the challenges of puberty while others have greater difficulty. This review explores how we might extend existing biocultural models to the context of ballet in order to garner a greater understanding of the pubertal transition. Future research should explore the interactions among social, psychological and biological factors during puberty in adolescent ballet dancers in order to document important determinants of adaptive responses at puberty and to inform future endeavours aimed at promoting healthy pubertal transitions among young dancers. [ABSTRACT FROM PUBLISHER]

The study aimed to evaluate the mediating effect of biological maturation on anthropometrical measurements, performance indicators and subsequent selection in a group of academy rugby union players. Fifty-one male players 14–17 years of age were assessed for height, weight and BMI, and percentage of predicted mature status attained at the time of observation was used as an indicator of maturity status. Following this, initial sprint velocity (ISV), Wattbike peak power output (PPO) and initial sprint momentum (ISM) were assessed. A bias towards on-time (n = 44) and early (n = 7) maturers was evident in the total sample and magnified with age cohort. Relative to UK reference values, weight and height were above the 90th and 75th centiles, respectively. Significant (p ≤ .01) correlations were observed between maturity status and BMI (r = .48), weight (r = .63) and height (r = .48). Regression analysis (controlling for age) revealed that maturity status and height explained 68% of ISM variance; however, including BMI in the model attenuated the influence of maturity status below statistical significance (p = .72). Height and BMI explained 51% of PPO variance, while no initial significant predictors were identified for ISV. The sample consisted of players who were on-time and early in maturation with no late maturers represented. This was attributable, in part, to the mediating effect of maturation on body size, which, in turn, predicted performance variables. [ABSTRACT FROM PUBLISHER]

In this study we tested for differences in physical activity (PA), physical self-concept, and health-related quality of life (HRQoL) between the least and most biologically mature adolescent females within their respective chronological and academic year groups. A total of 222 British female adolescents aged 10 to 14 years (X¯ age = 12.7 years; SD = .8) completed a series of instruments assessing PA, physical self-concept, and HRQoL. Percentage of predicted adult stature was used as an index of biological maturation. A series of univariate analyses of covariance (ANCOVA), controlling for chronological age, revealed that the most mature girls within the chronological and academic year groups generally reported lower levels of physical self-concept and, to a lesser extent, PA and HRQoL when compared to the least mature girls. The findings provide partial support toward the contention that maturity-associated variance in health-related outcomes is accentuated at the extreme ends of the biological maturity continuum. [ABSTRACT FROM AUTHOR]

A model for adolescent involvement in physical activity (PA) that incorporates individual differences in biological maturation is presented. The biocultural model of maturity-associated variance in physical activity recognizes PA as a complex and multifaceted behaviour that exists in multiple contexts (e.g., transport, vocation, sport, exercise) and can be viewed from multiple perspectives (e.g., energy expenditure, movement counts, performance outcomes, fitness). The model holds that biological maturation can exert both direct and indirect effects on PA during adolescence. Direct effects imply a direct and unmediated effect of individual differences in maturation on PA. Indirect effects imply influences of individual differences in maturation on PA that are mediated by psychological constructs (e.g., self-perceptions, beliefs) and/or are moderated by exogenous factors (e.g., social interaction, culture) associated with pubertal maturation. [ABSTRACT FROM PUBLISHER]

Abstract: The current study examined the mediating role of physical self-concept on relations between biological maturity status and self-reported physical activity in adolescent British females. Biological maturity status, physical self-concept and physical activity were assessed in 407 female British year 7–9 pupils (M age = 13.2 years, SD = 1.0). Participants completed the Physical Activity Questionnaire for Adolescents () and the Children and Youth Physical Self-Perceptions Profile (). Percentage of predicted adult height attained at measurement was used as an estimate of biological maturity status. Structural equation modelling using maximum likelihood estimation and bootstrapping procedures revealed that perceptions of sports competence, body attractiveness and physical self-worth mediated an inverse relation between maturity status and physical activity. The results provide partial support for Mediated Effects Model of Psychological and Behavioural Adaptation to Puberty within the context of physical activity. [Copyright &y& Elsevier]

Abstract: Purpose: To test the hypothesis that sex-related differences in exercise behavior during adolescence are confounded by biological age. Methods: Biological age and leisure-time exercise activity were assessed in 103 male and 83 female British Year 9 students (mean = 14.04 years, SD = 0.31). To assess exercise behavior, participants completed the Leisure-Time Exercise Questionnaire (LTEQ). Percentage of predicted adult height attained at measurement was used as an estimate of biological maturity status. Males reported more frequent engagement in strenuous forms of exercise and total exercise activity than females. Results: Sex differences in exercise behavior were attenuated and nonsignificant when biological maturity was controlled for. Conclusions: Sex-related differences in biological maturity contribute to sex-related differences in exercise behavior during adolescence. [Copyright &y& Elsevier]

The purpose of the study was to evaluate the developmental changes in performance in a repeated-sprint ability (RSA) test in young soccer players of contrasting maturity status. A total of 83 regional level Portuguese youth soccer players, aged 11-13 years at baseline was assessed annually. Stature, body mass, 7x34.2-m sprint protocol (25-s active recovery), 20-m multi-stage continuous shuttle endurance run and counter-movement jump (CMJ) without the use of the arms were measured. Fat-free mass (FFM) was determined by age and gender-specific formulas. Developmental changes in total sprint time across ages were predicted using multilevel modeling. Corresponding measurements were performed on an independent cross-sectional subsample of 52 youth soccer players 11-17 years to evaluate the predictive model. CA, CA2, maturational status (SA-CA), body size (mass and stature), FFM, aerobic endurance, lower limb explosive strength and annual volume training significantly improved the statistical fit of the RSA multilevel model. In 'late' maturing athletes, the best model for predicting change in RSA was expressed by the following equation: 86.54 - 2.87 x CA + 0.05 x CA2 - 0.25 x FFM + 0.15 x body mass + 0.05 x stature - 0.05 x aerobic endurance - 0.09 x lower limb explosive strength - 0.01 x annual volume training. The best fitting models for players who were 'on time' and 'early' maturing were identical to the best model for late maturing players, less 0.64 seconds and 1.74 seconds, respectively. Multilevel modeling provided performance curves that permitted the prediction of individual RSA performance across adolescent years in regional level soccer players. [ABSTRACT FROM AUTHOR]