Yes, When I was young I did horseriding and the local ponyclub had a small team doing this (but on a low level) I always found it very cool to watch.
There are a lot of gymnastics related sports that are interesting. Did you know of these for example?
It's quite popular in Germany. Young riders often practice it before or when beginning horse back riding in order to gain balance. I consider it a very good sport for children as it teaches not only balance and coordination but also teamwork and how to respect and care for a horse.
That being said and having spent close to 15 years both in the gym and on horseback I'm still very bad at it. It's a bit like BB only a lot livelier...
Yes, we know someone from Germany who used to do this. When she came here and learned about DD's gymnastics training, she started telling us all about how she used to do "horse vaulting." We had to pull up YouTube videos in order for us to understand. I was like, "What? You did gymnastics on top of a moving horse?" Indeed, she did. Crazy!