If you just have a normal dog, normally excited by moving balls, then desensitisation and a bit of routine training will see you through. If you have a genuinely obsessed dog though, then expect to spend a large slug of your life training to cope, and the rest of your life managing it. That's just the way it is, and the effort you have to put it if you really have an obsessed dog has to be seen to be believed. Anyone with a young puppy showing signs, head it off early if you can is all I can say....
I have a 1yr old lab who is absolutely football obsessed. It can become quite draining at this time of year when all the school kids have broken up and are out playing football in the park. I think what makes it worse is he will jump up to get it if it isn't on the ground. I am really struggling to know what to do. I end up putting him on the lead but he is doo bloody strong he almost rips my shoulder joint out trying to get to it.