Does your dog take you for a walk instead of you walking him? Have you tried to break him of the habit but been unsuccessful? Would you like a dog that walks on a regular flat buckle collar without pulling ? Have you taught your dog to heel but find it too regimented for long on-leash walks and would like to give your dog a little more freedom to sniff the ground, etc.? Read on!
The answer to how to stop the pulling can be found if we ask ourselves the question "Why do dogs pull?" The reason dogs pull is that they want to move forward, towards more interesting smells, other dogs, etc. To make things worse, the dog's natural pace is faster than ours, so they quickly find themselves at the end of a taut leash. They pull because pulling works: they want to go forward (often towards some specific thing) so they pull forward, and we relent by going forward with them. It doesn't take the dog long to figure out that pulling gets it to where it wants to go. The problem gets worse when the owner resists the pulling a bit. The dog then tries to pull harder and the owner finally gives in, resulting in a dog who learns that if they just keep pulling harder, they'll eventually get to where they want to go. The main secret to stopping a dog from pulling is to not allow pulling to get them where they want to go, and to teach them that they can go where they want (within reason!) when they don't pull. The other part of training involves teaching the dog that when it's on leash, it must pay at least some attention to where the person at the other end of the leash is.
The most common thing people do when a dog pulls is to yank on the leash. This method can work to teach a dog not to pull, but in many cases it has little or no effect, for several reasons. The first thing is that many dogs don't seem to mind being jerked with the leash. Often these jerks start as small ones and don't really have much effect on the dog, so the jerks get progressively bigger, but all the while the dog is building up a tolerance to them and gets pretty good at ignoring them. These leash jerks are our way of telling the dog that what it's doing is wrong, but we are generally very inconsistent with them. We let the dog pull until our arm gets tired, then we jerk the dog back. What this tells the dog is that most of the time it's okay to pull, but occasionally it's not. The dog has no idea when it's okay and when it's not, but most of the time it's okay (ie. no leash jerk comes), and the incentive not to pull isn't that big, so they pull.