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.