LOL well Kado is a runner at heart so very quickly. I tried using a regular nylon leash at that was pretty dangerous. He took to this right away and didn't require any training. It places him in a nice riding/running position. I have to watch him with small animals and barking dogs and this has helped take the worry out of that. It really forces the dog to stay in a heel position while giving a good amount of freedom and flexibility on the leash. I hardly notice he's there unless I let him do the pulling work. It's helped big time on road and on the mountain bike trails.