21.Aug.17 | Legacy

As parents, coaches and injury managers we look for the magic number regarding the amount of sport our kids should undertake. What is clear is that children and adolescents need to exercise. The question is do we know how much exercise and what type of training and play will optimise their athletic development rather than compromise it resulting in injury.

The recent study ‘The Youth Physical Development Model: A New Approach to Long-Term Athletic Development’ by Lloyd and Oliver (2016) gives a nice description of many different types of activity in strength and conditioning training and relates the type of training to the BIOLOGICAL or MATURATION age of the child.

In SUMMARY, before the ‘growth spurt’ that occurs in adolescence (the early teenage years), one should focus on basic strength, movement skills, speed and agility. It is important in this phase to jump, land and do strength activities to optimise bone development.

Once the ‘growth spurt’ begins one can take advantage of growth hormones and optimise muscle bulk with hypertrophy work (i.e. weights), power and sports specific skills BUT only if the athlete is competent.

YPD for females

The YPD model for females. Font size refers to importance; light pink boxes refer to preadolescent periods of adaptation, dark pink boxes refer to adolescent periods of adaptation. FMS = fundamental movement skills; MC = metabolic conditioning; PHV = peak height velocity; SSS = sport-specific skills; YPD = youth physical development.


While specific sporting load guidelines are limited across all sports, governing bodies of Cricket and Baseball have published articles which outline age appropriate fast bowling and pitching loads respectively to help minimise risk of injury in children. Furthermore, consensus statements exist to help guide how much time kids should be engaged in organised sport and training per week. These recommendations are outlined below.



Recently Cricket Australia published a number of guidelines surrounding fast bowling loads for adolescents. These have been designed to minimize the risk of injury.


Under 11 2 over limit each spell & 4 over limit per match
Under 13 4 over limit each spell & 8 over limit per match Target* of 100-120 balls per week
Under 15 4-6 weeks bowling preparation before the season 5 over limit each spell & 12 over limit per match Target 100-120 balls per week
Under 17 6-8 weeks bowling preparation before the season 6 over maximum each spell & 16 over limit per match Target 120-150 balls per week
Under 19 8-10 weeks bowling preparation before the season 7 over limit each spell & 20 over limit per match Target 150-180 balls per week

*weekly targets are a combination of training and match bowling



Elbow and shoulder injuries are common in adolescent baseball pitchers.  These injuries are often the result of overuse, poor conditioning or suboptimal pitching technique.

Recommendations to avoid these injuries were outlined by the American Sports Medicine Institute in 2013:

  1. Monitor levels of fatigue, often associated with deteriorating technique as well as with decreased accuracy or pitching speed. If these signs are beginning to surface, allow a break from pitching/throwing.
  2. Furthermore, if a child reports pain in the elbow or shoulder, cease throwing activities and seek an expert’s opinion.
  3. Allow a period of 2-3 months with no competitive overhead throwing per year.
  4. Prevent pitching duties on multiple teams with seasons that overlap.
  5. A child should not have both pitching and catching duties. This places too great a load on the upper limb with the throwing requirements.
  6. Ensure spikes in pitch counts are offset with increased rest in the days following.
  7. Pitching more than 100 competitive innings in a calendar year in considered an injury risk.
  8. Emphasise the importance of correct technique prior to a velocity focus.


A consensus statement from the American Orthopaedic Society for Sports Medicine recommends several measures to prevent burnout and injury in children including ‘avoiding over-scheduling and excessive time commitments’. (LaPrade, et al. 2016)

As a rule of thumb kids should limit the number of hours they participate in organised sports each week to the number of years they’ve been alive — or less. ‘So a 10-year-old should not play or practice more than 10 hours a week,’ (McGuine, et al. 2017)


  • Strict activity guidelines are scarce.
  • ‘Hours for age’ has no evidence but can be a guide.
  • No need to specialise early – a broad range of sports may be beneficial.
  • Be aware of stages of maturation – wait until late puberty and spurt before commencing ‘super heavy’ strength and plyometrics work.
  • Monitor pain, fatigue and wellness, and rest, sleep and eat well.
  • Avoid excessive spikes in load.




McGuine, T. A., Post, E. G., Hetzel, S. J., Brooks, M. A., Trigsted, S., & Bell, D. R. (2017). A Prospective Study on the Effect of Sport Specialization on Lower Extremity Injury Rates in High School Athletes. The American Journal of Sports Medicine, 0363546517710213.

LaPrade, R. F., Agel, J., Baker, J., Brenner, J. S., Cordasco, F. A., Côté, J., … & Hewett, T. E. (2016). AOSSM early sport specialization consensus statement. Orthopaedic journal of sports medicine, 4(4), 2325967116644241