RULE 141
Age Groups
The following definitions apply to the age groups recognised by IAAF:
Youth Boys and Girls: Any athlete of 16 or 17 years on 31st
December in the year of the competition.
Junior Men and Women: Any athlete of 18 or 19 years on 31st
December in the year of the competition.
Master Men and Women: Any athlete who has reached his/her 35th
birthday for stadia events and his/her 40th
birthday for out-of-stadia events.