I am now doing the stability ball work on its own. When I do it after the PUB, my arms are too tired to give me enough support to do more than a few pikes. When I'm fresh, this is much easier to accomplish, and I can keep up with Cathe. So, if you're having trouble, I recommend trying these exercises either before PUB or at another time. You'll be surprised at how much stronger you are when your arms aren't fried.