Breathless is the kind of workout you can adjust to stretch your athletic ability irrespective of your level of fitness. Go high on your jump squats and bring your knees to 90 degrees every time you do High Knees and try to get as high as possible with each of your jumping lunges and what you end up with is a kind of moving target that recedes in the horizon the fitter you get. Add EC and that horizon gets a tad further away, but that's just what keeps you coming back to this one.
Extra Credit: 1 minute rest between sets.
