"Leader walk" is to have the initiative when taking a walk with dogs. An owner should always walk first. The reason is that for dogs, walking is not just an exercise, but a movement (hunting) of a herd, and dogs recognize who walks first as the leader.
When dogs move in a herd, the boss of the herd walks first, and other dogs follow in line in order of rank. Many dog owners follow their dog and their dog walks first when taking a walk.
But for dogs, this position means that the dog is the leader and the owner who follows is a subordinate although the owner doesn't think so and doesn't notice.
By continuing the walk in which the owner plays the subordinate, the dog feels more and more superior, becomes more and more selfish, and finally it may become a dog that causes various problems.
Therefore, when you take a walk with dogs, you always have to take the initiative and walk first.