Clink Friesen describes the testing that he’s done with Red Bull Project Endurance.  Red Bull puts on a camp for several of its endurance athletes once a year to help them learn more about their physiology.  One of the hallmarks of the camp is that the athletes are tested at sea level in Death Valley and then tested at altitude on Mammoth Mountain to see how that affects their performance.  Clint comments on how athletes with different limiting systems respond differently to altitude.