There are very few breeds for which a “walk” would actually translate into meaningful being considered as exercising a dog. You can get a sense of whether what you’re currently doing with your dog might qualify as exercise by checking your own heart rate. Find out what your own heart rate should be if you were to have to consider your dog walk to qualify as exercise for your self. (Here’s webmd.com’s heart rate calculator). I think it’s a pretty good bet that unless yours is a toy breed you may have to pick up the pace to consider your outings to be meaningful exercise.
Meaningful exercise impacts not only a dog’s physical well being but also its mental well being. It impacts their ability to focus on lessons, retention etc. Introducing a dog to real exercise requires the same common sense as it does with people. Factor into how you’re going to go about it things like your dog’s age, breed, current physical condition, nutrition, the weather etc.
Here are some out of the box ways I’ve found people exercising their dogs.
Flatmill and/or Carpetmill
This is totally dog powered. If the dog stops so does the mill. You’d have to monitor pretty closely as I know a few dogs that would drop before they’d quit.