We have a 5lb boy Laddy who is a jumping machine and there has never been any stopping him (I think he was a cat in his past life
) Then we have Kyra who is 3lbs and we do not allow her to jump. She has a few times when we didnt catch her in time and scared the life out of me. I tried every way with Laddy from the day he came home to stop him jumping, some are just that way. Yes they are very fragile so I don't think you are worrying to much.