ABSTRACT
Chronological age provides a useful point of reference when referring to growth and maturity status but biological clocks do not run in accord with the calendar. Youth of similar chronological age display wide variability in the development of morphological and physiological characteristics. This is a major challenge in youth sport where competitions are regulated by age-groups. This chapter discusses age-group sport in relation to maturity status, describes the relative age effect, and explores age falsification and age verification in youth sport. It concludes with comment on the role of those involved in age-group sport.
