Anaerobic vs Aerobic with Emphasis on Intensity

Last rest day post had us exploring the different metabolic pathways and how having a balance in these pathways is CrossFits second model of fitness.

  It is worth digressing on a few points to illustrate the nature and relationship of the pathways, not to further understanding of bioenergetics, but to arm the athlete/trainer with a lexicon of the how and why of CrossFit’s WOD and resultant adaptations.  We seek to give the athlete/trainer a race car driver’s visceral intimacy of the race, versus the mechanical engineers encyclopedic knowledge of the car.  The digressions then will be a comparison and contrast of anaerobic vs aerobic exercise, and the crucial role Intensity plays in their relationship.

The adaptations of anaerobic vs aerobic exercise are not proprietary CrossFit material.  That is, they are not subject to intelligent debate.

  Having a balance of ten skills or a balance of the 4 pathways certainly have antagonists, but the differences herein are known facts the understading of which is axiomatic to further discussion.

Aerobic activity builds cardivascular health.  Anaerobic activity also delivers cardiovascular health at least the equal of aerobic activity.

Aerobic activity burns more fat than anaerobic work during exercise.  However, once aerobic work ceases the fat burning stops, whereas anaerobic activity delivers a whopping punch to the metabolism that stays revved for 12 to 18 hours and confers up to nine times the fat burning capacity of aerobic work.

Aerobic activity burns muscle.  Anaerobic activity builds muscle.  Look no further than the sprinters physique against the endurance runners physique (at least before CFEndurance entered the picture.)

Aerobic activity has detrimental effects on strength, speed, and power.  Anaerobic work builds strength, speed, and power.  And where aerobic activity has detrimental effects on the adaptations of anaerobic exercise, the reverse is not true.  On the contrary anaerobic activity improves aerobic performance, and without the intendant muscle wasting.

Anaerobic activity is high powered, where aerobic activity is low powered.  This is most easily observed as anaerobic activity being unsustainable past several minutes, contrasted to aerobic activity which has no drop off in output for any meaningful amount of time.

Power, if we remember, is one of our 10 physical skills and is the mathematical and definitional equal to Intensity.  This is critical on two points.  First, Intensity is the independent variable most commonly associated with optimizing returns.  If we wanted to isolate some quality of exercise that has positive results on adaptation versus degrading them, it is Intensity.  This is true of building muscle, burning fat, increasing VO2 max, lowering blood pressure, increasing neruoendocrine response, alleviating depression, and the list goes on.  It serves our purposes then to chase high intensity exercise.

Let us preamble the second point with what Intensity is not.  It is not heartrate or how loud you scream, nor is it how lousy you feel during or after a WOD.  These are only correlates, and maybe very good ones, but ultimately only correlates to what Intensity is.  Intensity is defined as force x distance/time (foot lbs per minute or derivatives of horsepower in humans) and is therefore subject to measurement.  I cannot overstate the value of this.  Here we have a quality that not only positively but optimally effects all known markers of adaption, AND we have a metric by which to evaluate it.  CrossFit’s WOD, seemingly random, is if you observe carefully very sensitive to, rewards, develops, recognizes and measures power.  It is made with a very heavy bias toward maximizing Intensity.  You can run, clean, squat, dead, push jerk, and pull up more mass and faster, than you can with calf raise, bicep curl, and seated swiss ball press.

We’ll adjourn this with a final comparison of anaerobic and aerobic qualities.  Anaerobic work is HARD.  It is the acme of discomfort.  It engenders misery to a point such that aerobic work is fun in comparison.  For benefits so great as anaerobic activity confers, this is it’s one true price.  To pay it, again and again, for the sake of increasing quality of life and maximizing return speaks to a mental fortitude and strength of character rarely found in everyday living.  Perhaps this is why CrossFitters bond so, but that is for another post.  Happy rest day.