Despite worrying evidence that British children, like their parents,1 lead a predominantly sedentary life,2 3 concerns continue to be expressed for those children who do take part in organised sport and who may be involved in intensive training from an early age.4 5 Injuries of all types in childhood account for a large part of the workload of accident and emergency departments and result in a significant number of deaths per year. However, deaths from sporting activity in childhood are rare, and are mainly associated with cardiovascular conditions such as hypertrophic cardiomyopathy and congenital coronary artery anomalies in boys.6 However, there remains the possibility that children who undertake intensive training and frequent competition may suffer the long term consequences of acute and overuse injury in later life. Over the past two decades it has been noted that the age of athletes taking part in competition and regular training in sports such as tennis, swimming, and gymnastics has been reducing.4 7This is a likely consequence of the ‘catch them young’ philosophy, the widespread belief that in order to achieve international success at senior level it is necessary to start intensive training well before puberty.4 These concerns have led to the issuing of guidelines for sports participation by children8 and warnings of increasing risk of acute and overuse injuries as children change from varied free play to the repetitive demands dictated by the specialised pattern of movement imposed by a single sport at high level.9 10