I don’t do Agility myself, but have many friends who do. When dogs are properly trained and conditioned (including things like not letting them jump full height until their growth plates are closed, teaching them to take their time on the contacts, etc), I have not really heard of many if any injuries to the dogs. Handlers, yes, I’ve known quite a few who’ve injured a knee or the like ;-) , but again, I think that has to do with proper conditioning.
If you are at all interested in it, I would find a good trainer - someone who competes and trains people who compete and talk to them about it. Most require that the dog’s basic obedience be fairly solid though, so you would want to start with that.