Get Back in Shape

I am enjoying Kendo practice, but I think I would enjoy it much more if I could get back in shape first. Right now I have difficulty completing the arm up exercises. And then I am muscle sore for the next 3 days. I was thinking that it would be nice to finish the warm ups, and still have some energy left :-)

So, my goal for a while is to train until I am able to finish the warm ups.