It's not cardio gentlemen.
The continued wrestling and knee towards the end of 3rd round did it. Body blows sap wind and power... People mistake it for "cardio." Watch boxing or Rampage beat up Liddell.
In grappling you learn to be dead weight. You expend less energy and you
are heavier. Positioning is control. JJ continued to fight through clinches and on the mat. Claudia had to continue to fight for position and expend energy. When wrestling, your whole body can be flexed the entre time.
Flex continuously, get drilled in the gut, and you will look like Claudia.