I took my first judo class tonight. I did scores of rolls in the 2.5 hours. The ground is hard, as I'm jacking the form like a n00b, and getting up a bajillion times is tiring, not to mention calesthenics before hand to warm up.
3 V02 and I was not out of breath in the least. It didn't even come close to phasing me, and not having that as a consideration is HUGE. LOVE IT!