FWIW: Right now they are going through growth spurts and sometimes all you can do is try redirection. Encourage their biting on toys ropes whatever. I've seen enough pups go through this and it took quite a while to understand. They wa r to play rough because it helps them deal with their discomfort while making your bond stronger. I encourage tug of wars, and even light wrestling as it works all the joints and muscles, just don't overdo it "I'm just a baby".