In the early 1900s it was thought that exercise directly stimulated growth; however, by the end of the century it was suggested that young athletes were selected based on inherited physical attributes that enhanced performance success. In this paper, the physical attributes and normal patterns of growth of young athletes, both competitive and recreational, are discussed. Specifically, the paper addresses the question, Are young athletes born with physical attributes suited to a sport or does sport training produce these physical attributes? Variability in the tempo and timing of normal growth and development is addressed, and its relevance and influence on youth talent identification is discussed. This is pertinent in today’s context of sport specialization at relatively young ages. Regular physical training is only one of many factors that could affect child growth; however, distinguishing influences of training programs on growth from those associated with normal growth and development is problematic.
Adam D.G. Baxter-Jones
Adam D.G. Baxter-Jones, Nicola Maffulli, and Robert L. Mirwald
Adam D.G. Baxter-Jones and Peter J. Helms
This paper reviews the findings from a longitudinal study following the growth and development of young British athletes. Four sports were studied: gymnastics, soccer, swimming, and tennis. Four main areas of concern were identified and studied: sports injury, growth and development, psychological and psychosocial problems, and physiological functioning. No evidence was found to suggest that training affected growth or sexual development. The incidence and severity of injuries was low. Athletes were shown to have a healthy lifestyle. The negative effects of intensive training at a young age were outweighed by the many social, psychological and health benefits that a serious commitment to sport brought these young people.
Adam D. G. Baxter-Jones, Joey C. Eisenmann, and Lauren B. Sherar
The process of maturation is continuous throughout childhood and adolescence. In a biological context, the effects of a child’s maturation might mask or be greater than the effects associated with exposure to exercise. Pediatric exercise scientists must therefore include an assessment of biological age in study designs so that the confounding effects of maturation can be controlled for. In order to understand how maturation can be assessed, it is important to appreciate that 1 year of chronological time is not equivalent to 1 year of biological time. Sex- and age-associated variations in the timing and tempo of biological maturation have long been recognized. This paper reviews some of the possible biological maturity indicators that the pediatric exercise scientist can use. As a result, we recommend that any of the methods discussed could be used for gender-specific comparisons. Gender-comparison studies should either use skeletal age or some form of somatic index.
Katie Crockett, Saija A. Kontulainen, Jonathan P. Farthing, Philip D. Chilibeck, Brenna Bath, Adam D.G. Baxter-Jones, and Catherine M. Arnold
A distal radius fracture (DRF) is commonly the first fracture to occur in early postmenopausal women. The reasons for sustaining a DRF may be related to fall risk, bone fragility, or both. The objective of this study was to compare functional and fracture risk status in postmenopausal women with and without a recent DRF and explore the relationships between function, grip strength, and fracture risk status. Seventy-seven women a ges 50–78 with (n = 32) and without (n = 45) a history of DRF in the past 2 years participated. Balance, timed up and go (TUG), gait velocity, balance confidence, sit to stand, grip strength, and fracture risk were assessed. There was a significant group difference after controlling for physical activity level (Pillai’s Trace, p < .05) where women with DRF had poorer outcomes on sit to stand, gait velocity, TUG, and fracture risk status. Grip strength was associated with functional tests, particularly in women with DRF. Women with a recent DRF demonstrated lower functional status and higher fracture risk compared to women without. Grip strength was associated with measures of function and fracture risk, and may complement screening tools for this population.
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.
Marta C. Erlandson, Shonah B. Runalls, Stefan A. Jackowski, Robert A. Faulkner, and Adam D.G. Baxter-Jones
Purpose: Premenarcheal female gymnasts have been consistently found to have greater bone mass and structural advantages. However, little is known about whether these structural advantages are maintained after the loading stimulus is removed. Therefore, the purpose of this study was to investigate the structural properties at the hip after long-term retirement from gymnastics. Methods: Structural properties were derived from dual-energy X-ray absorptiometry scans using the hip structural analysis program for the same 24 gymnasts and 21 nongymnasts both in adolescence (8–15 y) and adulthood (22–30 y). Structural measures were obtained at the narrow neck, intertrochanter, and femoral shaft and included cross-sectional area, section modulus, and buckling ratio. Multivariate analysis of covariance was used to assess differences between groups in bone measures while controlling for size, age, maturity, and physical activity. Results: Gymnasts were found to have structural advantages at the narrow neck in adolescence (16% greater cross-sectional area, 17% greater section modulus, and 25% lower buckling ratio) and 14 years later (13% greater cross-sectional area and 26% lower buckling ratio). Benefits were also found at the intertrochanter and femoral shaft sites in adolescence and adulthood. Conclusion: Ten years after retirement from gymnastics, former gymnasts’ maintained significantly better hip bone structure than females who did not participate in gymnastics during growth.
Lauren B. Sherar, Sean P. Cumming, Joey C. Eisenmann, Adam D.G. Baxter-Jones, and Robert M. Malina
The decline in physical activity (PA) across adolescence is well established but influence of biological maturity on the process has been largely overlooked. This paper reviews the limited number of studies which examine the relationship between timing of biological maturity and PA. Results are generally inconsistent among studies. Other health-related behaviors are also considered in an effort to highlight the complexity of relationships between biological maturation and behavior and to provide future research directions.