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Image by Nik Shuliahin
Image by Chiheb Chakchouk

For many years, the National Governing Bodies of sport and sports/fitness coaches have adopted the Long Term Athlete Development model of youth physical development (Istvan Balyi et al). This model analyses chronological and physiological age of an athlete and then seeks to offer ‘windows of opportunity’ for training youths to maximize performance potential in later life. However, this model is currently under examination by a number of academic researchers and coaches who believe there is more to youth athlete development. Here is a synopsis of the latest thinking with some important takeaways you can apply to your own youth athletes.



There are three ‘ages’ that can influence a youth’s athletic development:


  • Chronological Age refers to an athlete’s age in years. There are trends in chronological age development that may be useful for a coach to understand – for example, the onset of Peak Height Velocity (PHV) (the rate at which a child’s height increases fastest) will occur during puberty usually between the ages of 10-12 for girls and 12-14 for boys. PHV is a good indicator as to the endocrine changes that may well help an adolescent athlete advance their training. Therefore often chronological ages are used to help manage an athlete’s training programme.


  • Physiological Age refers to an athlete’s physical maturity. It does not use a ‘calendar’, but instead looks at the physiological characteristics of an athlete to determine their readiness for specific training programmes. Size, secondary sexual characteristics etc all give insight in physiological age.


  • Training Age refers to an athlete’s training history (and potentially therefore skill level and readiness to train). A longer training age would in theory make an athlete more ‘ready’ to take on specific training regimes. Training history needs to be continually accumulated to maintain and progress any training benefits achieved during each stage of physical development.



Physical development during childhood generally follows a nonlinear process, with periods of little or no change interspersed by periods of rapid development. Development (and therefore training recommendations) in specific areas of sporting ability are hard to define, with evidence between studies often conflicting.



Studies suggest that endurance should be actively developed throughout childhood and adolescence. There is no specific age when endurance should be extensively trained.



Children pre-PHV benefited most from plyometric and then sprint training, children circum-PHV benefited most from plyometric and then strength training, and children post-PHV benefited most from combined training methods (eg. strength + plyometric training) and then strength training alone. Children who were pre-PHV benefited most from training that has a primarily neural basis, whereas children post-PHV benefited from training that aims to strengthen the muscle and adapt morphological characteristics.



Gains can be made from age 5 – but only from a neural basis as muscle cross-sectional area will not develop until puberty. Strength gains are influenced by many factors including; neural development, muscle hypertrophy (driven by the onset of endocrine changes during puberty), changes in skeletal length causing biomechanical lever length changes.



The development of fundamental and sport-specific movement skills enhances physical literacy, and enables children to move confidently in a wide range of physical activity, rhythmic and sporting situations. Fundamental movement skills provide the basic building blocks for developing physical literacy, and incorporate activities designed to enhance stability (e.g. balancing, twisting, turning), locomotor skills (e.g. walking, running, hopping) and manipulative skills (e.g. throwing, catching, kicking). All FMS should be practiced throughout childhood as all will have a positive bearing on a child’s sporting potential – helping to prevent a ‘proficiency barrier’ that could impede the development of more complex skills.



Research has revealed that those who reached an elite status in sport actually trained less in earlier childhood than those who failed to reach an elite level! However, elite athletes did tend to increase their training more than their non-elite counterparts in late adolescence. This supports the theory that youngsters should sample a variety of sports between 6-12 years old, begin to specialise in a chosen sport(s) between 13-15 years old and then invest heavily in a sport from 16 years onwards if committed to achieving excellence.




The new Youth Physical Development Model has been developed to recognise changes in thinking around athlete development. Important notes are as follows:


  • Central to the model is a large emphasis on the development of muscular strength and movement competency throughout both childhood and adolescence.

  • Movement should be multi-sport with no single sport being prioritised unless the child’s preferred sport is categorised as an ‘early development sport’ (eg swimming or gymnastics).

  • Strength and conditioning exercises essential to future adult athlete performance should be incorporated into a child’s training when appropriate.

  • When planning a child’s physical development, consideration should be paid to the long-term efficacy of the training including their mental health and over-exposure to one single sport at a young age.

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