Two articles of the FEI Rules and Regulations are relevant in this regard:
A) Article 124.1 and 124.2 of the FEI General Regulations:
1. Athletes of the appropriate age may take part in FEI Competitions and FEI Championships of more than one (1) Category for Young Riders, Juniors and Pony Riders, but in each Discipline only in one (1) of these FEI Championships in any one (1) calendar year.
2. Athletes may take part in FEI Senior Competitions and Championships from the beginning of the year they reach the age of (eighteen) 18 but they may only take part either in a Junior or a Young Rider or a FEI Championship for Seniors in the same Discipline in any calendar year. Further exceptions regarding age limits are set forth in the Sport Rules of the relevant Disciplines.
B) Article 815.1 of the FEI Endurance Rules:
1. Any person from the year in which he/she reaches his/her 14th birthday and who is duly authorised by his/her National Federation is eligible to take part in all Endurance Rides (CEIs, CEIOs and Championships – Senior and Junior/Young Rider).
From the above mentioned articles it shall be concluded that:
- Athletes of the appropriate age (either Young Riders, Juniors or Children) can participate in FEI Endurance Championships ONLY in ONE of these categories (either Young Riders, Juniors or Children) in ONE calendar year;
- If a Young Rider or a Junior or a Children has participated in a FEI Endurance Championships in any of these categories in one calendar year, they CANNOT participate in other categories in the same year, including the category of Seniors.
- Article 815.1 of the FEI Endurance Rules ONLY sets an exception to the age limit to participate in FEI Endurance rides, subject to the conditions expressed in such article; but DOES NOT ALLOW to participate in FEI Endurance Championships in more than one category in one calendar year.