When you get your 8/10-week-old puppies, please keep this image in mind. Their bones do not even touch yet. They plod around so cutely with big floppy paws and wobbly movement because their joints are entirely made up of muscle, tendons, ligaments with skin covering. Nothing is fitting tightly together or has a true socket yet.
Early Age Exercise
It is very important not to have your puppy jar or stress their limbs until the bones have joined. Activities that can damage your puppy’s limbs are climbing stairs, jumping down from heights greater than themselves, falling down stairs, and even rough play with a larger dog.
When you run them excessively or don't restrict their exercise to stop them from overdoing it during this period you don't give them a chance to grow properly. Every big jump or excited bouncing run causes impacts between the bones. In reasonable amounts this is not problematic and is the normal wear and tear that every animal will engage in.
But when you are letting puppy jump up and down off the lounge or bed, take them for long walks/hikes, you are damaging that forming joint. When you let the puppy scramble on tile with no traction you are damaging the joint.
You only get the chance to grow them once. A well-built body is something that comes from excellent breeding and a great upbringing-BOTH, not just one.
Once grown you will have the rest of their life to spend playing and engaging in higher impact exercise. So, keep it calm while they're still little baby puppies and give the gift that can only be given once.
Do NOT over exercise your puppy. From the time you get them home, and up to 16 weeks, running around the house and back yard is enough exercise for their little limbs. From about 16 weeks you can gradually increase exercise from about 100 meters, making sure that your puppy does not become over tired. Increase the distance weekly until by about 12 month of age your dog will be ready for normal adult exercise of 2-5km or more each day.