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The Metabolic Pathways; Are you Missing the Point?

Before CrossFit was even a thing, Greg Glassman was writing blog articles describing his theories on fitness.   In his original article titled What is Fitness, Glassman describes four fitness models.  They are: 

        • The 10 General Fitness Skills
        • The Hopper
        • The Sickness, Wellness, Fitness Continuum
        • The Metabolic Pathways  

For each of these models, Coach Glassman describes in depth his theories of fitness.  Unfortunately in today’s day and age of CrossFit, I believe most people don’t understand or have even heard of Glassman’s ideas.  If we focus on the Metabolic Pathways model, I truly believe that many people are not as “fit” as they think.  

When talking about the metabolic pathways, the three that we know of are the phosphogen, glycolytic, and the oxidative (if we eventually discover more, we should train in these pathways as well). Let’s explain the pathways.  The three metabolic pathways provide energy for all human action.  The phosphogen pathways powers activities that last only a couple of seconds- think of a snatch.  The glycolytic pathway is for moderate power activities that last up to several minutes- think of going for a 400m sprint.  Finally, there is the oxidative pathway which powers activities that last for long term workouts- think of your 15-20 minute continuous workout.  This is not new science here, even if most didn’t know they were training for these pathways, which is why many body builders can be seen resting for several minutes between sets.  The phosphogen pathway gives you a fast dose of energy but takes several minutes after to reset and get back to its original level.  The glycolytic pathway takes longer to deplete but again needs several minutes to completely reset.  Finally the oxidative pathway slowly depletes and take the longest to recover from.  

You can probably start to see where you may be biasing your workout.  Most CrossFitters tend to bias their workouts in the realm of the oxidative system. I have come to notice that most athletes today are living solely in the oxidative pathway.  They are completely negating the phosphogen and glycolytic.  I believe people have come to think that if they don’t workout for 15-20 minutes that they are not getting a “good workout” in.

CrossFit has a bad reputation among some communities as not having strong athletes.  Strength being defined as “the ability of a muscular unit, or combination of muscular units, to apply force”.  Part of the reason for this is criticism is because in most CrossFit metcon workouts you train muscular endurance and not strength.  The pathway required for high levels of strength has already been depleted and you are training the oxidative pathway.  If you are to be truly fit, there have to be days where you train the pathways that require great amounts of power and short spurts of energy.  Training different pathways also means understanding the recovery times required to give certain efforts.  To understand this, one needs to look at the snatch movement (which is a movement where one will take a barbell from the ground to the overhead position in one fluid motion). Anyone who has attempted a 1-rep maximum snatch knows the feeling.  You hit a heavy lift so you add five pounds to the bar and then are unable to lift the bar past your hips.  It’s crazy to think how just 5 pounds made the lift so difficult.  This is an example of how the different pathways affect different movements.  Inversely, a great weightlifter who can snatch over 300 pounds will struggle to perform 30 snatches for time as fast as possible at 135 pounds.  This just goes to show that just because you are strong or just because you can run a marathon does not mean you are fit.  A truly fit person can perform across all three metabolic pathways.  

There are more factors to becoming fit than how long you workout.  Being able to perform at a high level across all metabolic pathways is a key way to define how fit you are.  The hardest part of being an athlete is knowing your weaknesses.  If you only train at the pathway you are good at you are fooling yourself to believe how fit you are.  Make sure to train those fast movers.  Have those “heavy single” days in weightlifting and make sure to do those 200 and 400m sprints.  These days are critical for overall fitness.  

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