Do you take your dog for a walk, or does your dog take you for a drag? If you have a hard time keeping up with your dog on a walk, the extra weight will help calm them down. While you are out walking with your dog, the extra weight will also help them build muscle.
Furthermore, If your dog is very active, the weighted vest is a good way to help them burn off some extra energy while they are running around the back yard. If you have a dog that is overweight, a weighted vest can help your friend get back to a healthy weight.