in an indoor riding school you can not do a perpendicular
i thin it is The diagonal
It only depends on how small the indoor is. If it is large you can do any figure in an outdoor ring.
It sounds much like indoor soccer.
Indoor sports are just indoor sports. But if you want to get specific then you might say indoor soccer, indoor tennis, indoor football, etc.
when he is inside the designated area wether it be a semi circle or a bigger box
It is an indoor sport.
The word 'indoor' is generally used as an adjective, as in 'indoor activities', indoor swimming pool', etc.
An indoor riding arena is an indoor area where you can ride horses.
An indoor school.