Long narrow run areas encourage dogs to get more exercise. Recommended length is 20 to 30 feet depending on available space. A 4 - foot neckline allows ample freedom for the dog to jump on top of his house. With more that one dog, parallel runs take up the least amount of space and work best to encourage chasing type exercise. Runs should be placed far enough apart so that the dogs can touch but cannot get tangled with one another. With the lines set about one foot above ground level dogs become adept at footwork in avoiding the line - useful behavior for sled dogs.