I'm in the red shirt. The guy in the black shirt was one of my instructors in the school about 5 years ago. His background before Kung Fu was boxing and he used it on me. He has great endurance and at the time, my endurance was about the same as chain smoker with one lung. I've gotten much better since, but at the time, I was learning just how bad my cardio was. It was also the first time in about 40 years to spar without shoes. I was so used to having a certain amount of grip and I had none of that. It changed my entire game plan right from the start.