My cardio is hurting

I just cranked out some Burpee intervals from the RossTraining website.

http://www.bodybuilding.com/fun/rossboxing2.htm

It was very painful and I didn't get far enough to note anything yet other than "needs improvement".

To be fair this can't be a beginners workout and probably isn't where I should have started but it is. If I was more practical I'd start with straight burpees alone, omitting the jump even...but I guess I felt like jumping in with both feet. Ha ha jumping with both feet.

I think I'll stick with the intervals but modify it by doing declining sets of the burpee portion 8,7,6.. etc (adjusting as necessary) but keep the shadow boxing at 30 seconds. By the way 15 seconds into my second set of shadow boxing and I was really looking to shoot for a double leg takedown. :)