Cardio/Respiratory Endurance

Greg Glassman wrote an amazing article on “Metabolic Conditioning” in June of 2003.  I would encourage you to get a subscription to the Crossfit Journal (it’s only $25 and worth every penny) to read the entire four page article when you have a few minutes.  The article explains metabolic conditioning, or stamina, as the ability of the body systems to process, deliver, store and utilize energy.  It breaks that down into three pathways, the phosphagen, glycolytic and oxidative pathways.  The first two are primarily utilized during anaerobic activities (exercise lasting up to several minutes/no oxygen required), where as the last is the primary pathway for aerobic activities (in excess of several minutes/requires oxygen).   Crossfit defines cardiovascular/respiratory endurance as the ability of body systems to gather, process, and deliver oxygen, so we could get wrapped up in the oxidative pathway.  However, Crossfitters (and one could argue that everyone) need all three and research has shown that intense work in the first two pathways will increase one’s capacity in the third.  The kicker here is that conventionally, to train for cardio/respiratory endurance, one would go run/bike/swim for miles upon miles, day after day.  This of course would work to increase their cardio-respiratory endurance, but it would also decrease their muscle mass, thus making them weaker and often one dimensional.  (Christian-this may help to explain why in the past, whenever you “leaned out” you lost strength.)  Now, I don’t know about you, but if I can run for hours, but can’t put a heavy bag of dog food in the trunk, that doesn’t seem very functional.  We’d like everyone to be able to do both, so we’ll do a lot of work in the first two pathways and occasionally dip into the third, thereby increasing our bodies’ ability to gather process and deliver oxygen.  Read more about cardio/respiratory endurance and metabolic conditioning in the Crossfit Journal.


3x5 Shoulder Press


7x1 Snatch

Great job everyone!


Kayla learning the front squat...