Greetings from Germany.
As far as warm-ups are concerned, I have found that 25 hanging leg-lifts not only increase your heart-rate, but leave your brow on the sweating side. Personally, after completing 25 hanging leg-lifts, I know that I have been put the wringer, but not as though it has warped my entire energy.
I never do Cardio find my hanging-leg-lifts, suffice. Then in between my heavy resistance training, I will return to the hanging leg lifts and hanging knee lifts. In addition, for my ABS, I love to perform rope crunches on my knees, never raising fully erect but raising only to waist level, keeping time under tension.
That's all the Poop from this side of the Cesspool.