Why is horseback riding a sport?

There’s a 71 year old dressage rider in the Olympics so it seems to take litle physical effort.. Not trying to be rude, I genuinely wanna know.

Comments on "Why is horseback riding a sport?"
More: I fed my 6 year old ball python ate two large mice a few days ago, what he is normally fed. Yet he is striking at me like he is still hungry? What is wrong with my dog? Is a high 20 gallon tank good for a baby Bearded dragon? How did my rat die? Is this space big enough for my lion haired rabbit?