No breed is impossible to obedience train, but novice owners might find training some breeds quite difficult. The capacity to learn basic obedience—and even complicated behavior—is inherent in all dogs. Some breeds may require more patience or creativity in training than others. Individual dogs that exhibit fearful or anxious behaviors should also be handled with greater care, and especially not trained using harsh corrective methods, as this training can be psychologically harmful to the dog and result in further behavioral issues.
There is an ever-growing list of agility sanctioning organizations. The ones you’ll hear about most often in the US are NADAC, AKC, and the USDAA (see below for a more complete list of national and international groups). Each organization has its own rules and style. For example, NADAC courses are spread out and focus on speed. They often challenge the handler to send their dog through the course at a distance. USDAA courses are “tighter” and more technically challenging.
If your dog is refusing to go over a hurdle, practice in a narrow hallway. Set up a small jump and put your dog on one side with you on the other. Your dog should have nowhere to go but forward over the jump. Encourage your pup with treats and a happy tone of voice. With a little patience and positive reinforcement, your dog will soon be a confident jumper.