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This study examined differences in physical activity and physical self-concept between the least and most biologically mature female adolescents within chronological age and academic year groups. A total of 252 British female adolescents (M age = 12.9 years; SD = 0.7) in Years 7-9 completed self-report measures to assess physical activity and physical self-concept. Percentage of predicted adult (mature) stature served as the index of biological maturation. Univariate analyses of covariance, controlling for decimal age, revealed that the least mature girls generally held higher perceptions of physical self-concept but were no more, or less, active than the most mature girls. A subsequent meta-analysis suggested, however, that across age and year groups the least mature girls were more active than the most mature girls. (Contains 4 tables.)

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[bar] age = 12.7 years; SD = 0.8) 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. (Contains 4 tables.)

This study investigated the associations between biological maturation status (classified using the Khamis–Roche method for the percentage of predicted adult height at the time of observation) and relative age (expressed as a decimal value relative to the difference between birth date and competition cut-off date) and the extent to which their relative selection biases existed across competitive age groups in an analysis of players within the Football Association of Ireland's (FAI) national talent pathway. The players assessed were either from the U13 FAI National Academy (n = 125), the Ireland U15 national team (n = 18), or the Ireland U16 national team (n = 16). A moderate to very large selection bias in favour of early maturing players was observed across all age groups, increasing in magnitude with successive age groups (p < 0.05). A total of 46–72% of players selected into the national talent pathway were early maturing; 0% of U15 and U16 players were late maturing. A relative age effect existed across all competitive cohorts (p < 0.05), although not increasing with chronological age and smaller in magnitude than maturation biases. A small positive correlation between relative age and absolute maturity status at U13 was observed, and an inverse correlation between relative age and relative maturity status at U15 (p < 0.01) was observed. There were no other significant correlations between relative or absolute maturity status and relative age. We encourage Football Associations to critically reflect upon their criteria for national talent squad selection; the current system diminishes the chances of selection for late maturing players. [ABSTRACT FROM AUTHOR]

Background: Skeletal age (SA) is an estimate of biological maturity status that is commonly used in sport-related medical examinations. This study considered intra-observer reproducibility and inter-observer agreement of SA assessments among male tennis players. Methods: SA was assessed with the Fels method in 97 male tennis players with chronological ages (CA) spanning 8.7–16.8 years. Radiographs were evaluated by two independent trained observers. Based on the difference between SA and CA, players were classified as late, average or early maturing; if a player was skeletally mature, he was noted as such as an SA is not assigned. Results: The magnitude of intra-individual differences between repeated SA assessments were d = 0.008 year (observer A) and d = 0.001 year (observer B); the respective coefficients of variation were 1.11% and 1.75%. Inter-observer mean differences were negligible (t = 1.252, p = 0.210) and the intra-class correlation coefficient was nearly perfect (ICC = 0.995). Concordance of classifications of players by maturity status between observers was 90%. Conclusion: Fels SA assessments were highly reproducible and showed an acceptable level of inter-observer agreement between trained examiners. Classifications of players by skeletal maturity status based on assessments of the two observers were highly concordant, though not 100%. The results highlight the importance of experienced observers in skeletal maturity assessments. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine intra- and inter-observer agreement for the three skeletal ages derived from the TW2 method among male pubertal soccer players. The sample included 142 participants aged 11.0–15.3 years. Films of the left hand-wrist were evaluated twice by each of two observers. Twenty bones were rated and three scoring systems used to determine SA adopting the TW2 version: 20-bone, CARPAL and RUS. Overall agreement rates were 95.1% and 93.8% for, respectively, Observer A and Observer B. Although, agreement rates between observers differed for 13 bones (5 carpals, metacarpal-I, metacarpal-III, metacarpal-V, proximal phalanges-I, III and V, distal phalanx-III), intra-class correlationa were as follows: 0.990 (20-bone), 0.969 (CARPAL), and 0.988 (RUS). For the three SA protocols, BIAS was negligible: 0.02 years (20-bone), 0.04 years (CARPAL), and 0.03 years (RUS). Observer-associated error was not significant for 20-bone SA (TEM = 0.25 years, %CV = 1.86) neither RUS SA (TEM = 0.31 years, %CV = 2.22). Although the mean difference for CARPAL SAs between observers (observer A: 12.48±1.18 years; observer B: 12.29±1.24 years; t = 4.662, p<0.01), the inter-observer disagreement had little impact (TEM: 0.34 years: %CV: 2.78). The concordance between bone-specific developmental stages seemed was somewhat more problematic for the carpals than for the long bones. Finally, when error due to the observer is not greater than one stage and the replicated assignments had equal probability for being lower or higher compared to initial assignments, the effect on SAs was trivial or small. [ABSTRACT FROM AUTHOR]

Within a group of adolescent Australian Rules Football (ARF) players, individuals of the same chronological age can differ greatly in biological maturation, with some players maturing vastly earlier or later than their peers. Such large differences in maturity can cause a disparity between physical performance, influence the perceptions of talent, and affect training practice. In attempts to address such issues, this overview proposes the concept of bio-banding in ARF, which may be used periodically within the national talent pathway to optimise player development. Bio-banding is the process of grouping adolescent athletes into specific categories or 'bands' based on biological maturation, rather than chronological age. This review describes how bio-banding may be used to enhance player development in ARF, giving context to its background and implementation in other sports. [ABSTRACT FROM AUTHOR]

The purpose of the study was to evaluate predicted maturity offset (time before age at PHV) and age at PHV (chronological age [CA] minus maturity offset) in a longitudinal sample of 58 under-13 club level soccer players in central Portugal for whom ages at PHV were estimated with the SITAR model. Two maturity offset prediction equations were applied: the original equation which requires CA sitting height, estimated leg length, height and weight, and a modified equation which requires CA and height. Predicted maturity offset increased, on average, with CA at prediction throughout the age range considered, while variation in predicted maturity offset and ages at PHV within CA groups was considerably reduced compared to variation in observed ages at offset and at PHV. Predicted maturity offset and ages at PHV were consistently later than observed maturity offset and age at PHV among early maturing players, and earlier than observed in late maturing players. Both predicted offset and ages at PHV with the two equations were, on average, later than observed among players maturing on time. Intra-individual variation in predicted ages at PHV with each equation was considerable. The results for soccer players were consistent with similar studies in the general population and two recent longitudinal studies of soccer players. The results question the utility of predicted maturity offset and age at PHV as valid indicators of maturity timing and status. [ABSTRACT FROM AUTHOR]

Talent identification and selection in soccer has been shown to be confounded by individual differences in relative age and biological maturation. Limited research has however, investigated whether these effects are reflected in coaches' evaluations of performance. This study investigated relative and biological age associated differences in coach perceptions of performance in a professional soccer academy across four seasons. The performances of 279 male players were evaluated on a 4-point Likert-scale. Multi-level modelling was used to examine predictive relationships between biological age, chronological age, result and opposition of game, on match grades. Result of the games was a statistically significant predictor of players perceived performance in every age-group; category of opposition was only significant in the under 13 and 14 age-groups. Biological age significantly predicted players perceived performance grades in the under 10, 14 and 15 age-groups, whereby advanced maturity predicted a higher grade. Across all age-groups, a relative age effect was observed, however age half was not a significant predictor of perceived performance grade in any age-group. Coaches evaluations of match performance appear to vary in accordance with maturity, opposition, and result of game. Academy staff should recognise and account for individual differences in biological maturation when retaining and releasing players. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. Evaluating performance relative to developmental curves and maturity status may be a practical means of monitoring long-term athlete development in tennis. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to examine the contribution of chronological age (CA), skeletal maturation, training experience and concurrent body size descriptors, to inter-individual variance in left ventricular mass (LVM) among female adolescent soccer players.Methods: The sample included 228 female soccer players 11.8-17.1 years. Training experience defined as years of participation in competitive soccer (range 2-9 years), was obtained by interview. Stature, body mass and skinfolds (triceps, medial calf) were measured. Fat mass was estimated; Fat-free mass was derived. LVM was assessed by echocardiography. Skeletal maturity status was as the difference of skeletal age (SA, Fels method) minus CA.Results: Fat-free mass was the most prominent single predictor of LVM (R2 = 36.6%). It was associated with an allometric coefficient close to linearity (k = 0.924, 95%CI: 0.737 to 1.112). A significant multiplicative allometric model including body mass, fat-free mass, CA, training experience and skeletal maturity status was also obtained (R = 0.684; R2 = 46.2%).Conclusion: Stature has limitations as a valid size descriptor of LVM. Body mass, fat-free mass, training experience, CA, body mass and skeletal maturity status were relevant factors contributing to inter-individual variability in LVM. [ABSTRACT FROM AUTHOR]

Background: Individual differences in biological maturation impact player selection and development in youth football. Aim: To evaluate players perceptions of competing in a football tournament where they were matched by maturity rather than chronological age. Subjects: Participants included male junior footballers from three professional academies (n = 115). Methods: The study employed multiple methods of analysis, including one sample mean t-tests, equivalence tests, ANOVAs, and thematic analysis of qualitative data derived from open-ended questions. Results and conclusions: Player's perceived the bio-banding format as providing two main benefits. Early maturing players perceived greater physical and technical challenge, and in turn new opportunities and challenges. Late maturing players perceived less physical and technical challenge, yet greater opportunity to demonstrate technical and tactical abilities. The players reported that they enjoyed and understood the purpose of the bio-banded format, and perceived less risk for injury. Players in all three maturity groups reported more opportunity to engage in leadership behaviours, influence game-play, and express themselves on the ball in the bio-banded format. Bio-banding may facilitate development for both early and late maturing academy players by presenting new learning environments and challenges. [ABSTRACT FROM AUTHOR]