[littlelo]

It is true they can turn on and stop quickly. That is what barrel horses do. It depends on how "hot" he is. Some barrel horses don't get hot until they see the arena or the barrels. My friend has a great barrel horse she goes trail riding with and she does fine. Once that horse sees the arena or sees a barrel it's a whole new story. My horse doesn't get hot ever. She can be a mare at times but I've never had any issues taking her trail riding.
If you ever run him on a trail he might get warmed up and want to run a bit. It just depends on the horse. I would ask to ride him. Get on him and feel him out. Feel how sharp and sudden he turns when you ask. Ask them how he did with the races themselves. was he a horse that loved his job and loved to run or did he do it because he was told to?