We live in a 3rd floor apartment and have been able to train Fuji to come up and down the stairs pretty successfully although he's still learning. Our question is, though, we sometimes worry that it's bad for him, especially at such a young age. Maybe it's bad for his growing bones? Or maybe it can lead to hip problems later in life? Sometimes he wimpers and acts like he doesn't want to and other times he seems fine. We were told not to run with him yet when we go for runs so I feel like there must be a correlation. At some point he'll have to go up and down the stairs when he's bigger but what about now?