HOW MUCH EXERCISE DOES MY DOG NEED?
That will depend on its breed, but also on its character as an individual and its age. The gigantic breeds or the very heavy ones can injure their bones and articulations if they exercise in a very intense way while growing up. In general, it is better for the puppies to go for many walks a day rather than a single marathoner walk a day.
If a puppy begins to look tired, walk slowly or deny going forward, it is evident that you have caused an over-effort on it. Don't forget that at this age the dogs take walks just to meet the world and get used to things more than to exercise, properly said. The same thing can be said about readopted dogs, which previous owners used to exercise only a little. Dogs, like us, have to get in shape gradually to avoid injuries in the muscles and articulations.
From the nine month on, all breeds, except the gigantic ones, can exercise in almost an unlimited way, as well on hard floor as on grass. But you shouldn't teach them to jump until they are one year old. Even when they train to compete on agility contests at this age, the training sessions are centered on the obedience and trust in themselves, leaving the jumps for later on.