With increasing emphasis placed upon excellence in sport, there is now a widely held belief that to achieve success, particularly at national or international level, training and competition should begin at an early age, well before the onset of puberty. Some are concerned about the possible negative effects of intensive training at such a young age. Much anecdotal evidence suggests cases of over training and competitive pressure leading to young athletes’ premature retirement from sport, although little scientific evidence has validated these impressions. In …