The main purpose in puppy training is to build a communication system between the two of you. You are teaching your dog how to learn. In contrast to the positive approach of puppy training, many obedience classes use a lot of leash jerking and a certain amount of punishment if the dog is not performing well. There is a fine line between the two attitudes and it is a vitally important difference.
With a young puppy, if you are forcing him to perform perfectly and punishing him even mildly if he does not, you may be asking for trouble later on. After a puppy is six to eight months old, he can usually begin to handle corrections and accept much more firmness when training your puppy but not at three, four and five months of age.
Stress should not be a specific part of training your puppy. That comes later when the pup is six to eight months old and ready for a more formal training. Of course, it is not possible or necessary to completely avoid stress because there is often a small amount in any of a puppy’s activities.
However, stress should be eliminated as a planned part of the actual puppy training.