Member  in good standing of The Canadian Kennel Club,
 2010 Tyramara Red'g, All Rights Reserved
Purposely bred with predictability in temperament, attitude and structure, generation after generation!
Every time I sell a new puppy, I always make sure to stress this information. When you get your 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.
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 a problem and is the normal wear and tear that every animal will engage in. But when you're letting the puppy jump up and down off the couch or bed, take them for long walks or 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, a great upbringing and a proper diet! Not just ONE of these things, but all of them

Once grown you will have the rest of their life to spend playing and engaging in higher impact exercises. So keep it calm while they are still little baby puppies and give them the gift that can only bed given once.

Also please note: most puppies growth plates don't close until 9 to 10 months and the joints aren't considered fully mature until 24 months. Normal play and exercise is healthy...excessive exercise is not. 

As you can see in these xrays, there is a fair amount of space between the bones