Martingale collars (also called limited-slip collars) are usually made of flat nylon with a smaller fixed-length section (made of either nylon or a short length of chain) that, when pulled on by the leash, shortens up tightening the collar around the dog's neck, to a limited extent. When properly fitted, martingales are looser than flat-buckle collars when not tightened, and less severely corrective than slip collars when tightened.
But wait, there’s more! Agility gives you something cool to do with your dog. This is important if you have a hard time getting your dog to do what you say. It teaches Fido that you are lots of fun and worth listening to. Compare this to another common activity for dogs: the dog park. At the dog park, you let him off leash and he goes off to do his own thing. Returning to you is no fun because it means he has to go home. You’re not Fido’s best buddy. You’re his chauffeur.
Clicker training, a common form of positive reinforcement, is a simple and effective dog training method. Although it is still fine to train your dog without clicker training, many people find it helpful. With clicker training, you can easily and effectively teach your dog all kinds of basic and advanced commands and tricks. It's fast and easy to learn how to clicker train your dog