German Shepherd Q&A
when they get tired, they'll stop running
Let your puppy run and play as much as it wants. You can walk about as far as you wish. I would recommend that you don't take him on jogs or bicycle rides where he has to run at a set constant speed until he is around a year old to let his bones and joints develop. Prior to that it is better to let him run off-leash and speed up, slow down, stop, etc. at his own pace if you have a location that you can safely allow this.
do NOT let them off leash in an unsecure area. They will be gone in no time flat, esp puppies
I would take very short walks if you are on a hard surface like asphalt or concrete. You do not want to run them on a road. It is a good idea to socialize them in a public place, shopping center, Little League game, where they can meet new people and see and hear strange sounds. When I walk puppies around our farm they probably go for a 20-30 minute walk, but they are playing , stopping, learning to come when called, and they cam stop when they feel like it. Do not make them walk if they are tired.