I ride horses competitively sometimes, it's also known as dressage.
That is very cool. It looks very fun.
It's considered a very honorable and prestigious sport, also known as the highest expression of horse training.
I did not know that. How long have people been riding competitively? 
I'm not sure exactly, but I think the history is long. It's even a sport at the Olympics and World Equestrian Games.
What kind of equestrian events are there in the Olympics?
Right now the current disciplines are dressage, eventing, and jumping.
Has it always been in the Olympics?
It wasn't at the 1904 or 1908 Olympics, but it's been there every time since 1912.