ABSTRACT
An individual’s genotype defines the potential for growth and maturation, but whether genetic potential is fulfilled is regulated by the endocrine system and influenced by energy availability and nutritional status. This chapter reviews energy availability, key hormonal axes, and essential nutrients in relation to the demands of youth athletes engaged in multiple acute exercise sessions, long-term, high-intensity training programmes, and regular competition. It explores contemporary issues including legal and illegal performance-enhancing supplements, disordered eating, eating disorders, and the development of the relative energy deficiency in sport (RED-S) syndrome.
