YOur dog trainer told you that a former ratting dog, puppy, isnt supposed to run?????
WOW! Keely is 8 months old and has been jogging with me everyday since i got her!
Its the large breed dogs that have problems. Because they grow so fast and there joints need time to catch up before they can excersize too much. But even they need daily walks/joggs..
I think you SHOULD be walking/jogging her daily. If anything, you wouldbe doing her a favor.