First, you need to acquire a medium-sized geriatric dog, about 60 pounds should do the trick. You need to make sure that the dog has reached the age where it can no longer go up and down stairs by itself. You need to live in a split-level home for this work-out to be most effective. The more stairs the better.
Now, several times throughout the day, whenever the dog needs to "do its business," you need to carry the dog down the steps. When she is done taking care of business, carry her back up the steps. You may also need to carry her out of the kitchen, or any other slippery-floored place, when she falls over and can't get herself up again.
Here is my own personal geriatric dog.