Although delayed menarche and alterations in reproductive hormones are well documented in competitive female runners, little is known regarding the effects of endurance training in male athletes. Serum levels of total and free testosterone were determined in 15 adolescent male cross-country runners during the course of a competitive season. Thirteen demonstrated postpubertal Values at the onset of the season. No significant changes were observed in either total or free testosterone levels during the eight-week period of training and racing. The data indicate that running training does not disturb normal function of the hypothalamic-pituitary-gonadal axis in high school male athletes.
The growing participation of children and adolescents in competitive sports has been viewed by the medical profession with a mixture of supportive enthusiasm and cautious concern.1 While regular exercise may be promoted for a variety of health benefits, the risks to the immature, developing athlete involved in highly intense training