Please find the official CrossFit Journal article at the bottom of this page, which you can download and read on your own!

CrossFit seeks to improve fitness in human beings of all ages, shapes, and conditions.  However, to quantify this claim, we must first define “fitness”.


/ˈfitnis/ Noun

  1. The condition of being physically fit and healthy.
  2. The quality of being suitable to fulfill a particular role or task


Coach Glassman (CrossFit’s founder) felt this definition was pretty circular and definitely not descriptive enough to determine whether or not CrossFit was actually increasing fitness levels.  As a result he set out to come up with his own definition of fitness that was not only quantifiable but also granularly descriptive. In his work of redefining fitness, he came up with three generally acceptable models of fitness that can be used to define fitness levels.


The three standards cover three modalities of physical achievement:  Increased physical skills and abilities over both a wide range of activities and over all time domains. Here are the Three Standards of Fitness as defined by CrossFit:

Competency in the ten general physical skills of fitness:

  1. Cardiovascular/respiratory endurance – The ability of body systems to gather, process, and deliver oxygen.
  2. Stamina – The ability of body systems to process, deliver, store, and utilize energy.
  3. Strength – The ability of a muscular unit, or combination of muscular units, to apply force.
  4. Flexibility – the ability to maximize the range of motion at a given joint.
  5. Power – The ability of a muscular unit, or combination of muscular units, to apply maximum force in minimum time.
  6. Speed – The ability to minimize the time cycle of a repeated movement.
  7. Coordination – The ability to combine several distinct movement patterns into a singular distinct movement.
  8. Agility – The ability to minimize transition time from one movement pattern to another.
  9. Balance – The ability to control the placement of the bodies center of gravity in relation to its support base.
  10. Accuracy – The ability to control movement in a given direction or at a given intensity.
How many of the 10 attributes of sport are at play here?

The Hopper Test: In the world there are an infinite number of physical activities that one can perform; from standard sport and exercise to war and everything in between. Pretend we placed that infinite list into a bingo hopper and selected activities one by one in a completely random manner.  The amount of competency a person has over each random task would be a measure of fitness.  Therefore, a fit person could handle any activity drawn out of this hopper with a level of competency.

Behold. The energy pathways.

The Energy Pathways Test: Humans generally operate on three energy systems: Phosphagen, Glycolytic (Anerobic), and Oxidative (Aerobic).  The third standard of fitness maintains a fit person has training and competence when working in all three of these energy pathways.

  1. The Phosphagen system – This system is used only for very short durations of up to 10 seconds.  This is the primary system behind very short, powerful movements like a golf swing, a 100 m sprint or powerlifting.
  2. Glycolytic System – Predominates in supplying energy for exercises lasting less than 2 minutes.  An example of an activity of the intensity and duration that this system works under would be a 400 m sprint.
  3. Oxidative System – This is the long duration energy system. By 5 minutes of exercise the O2 system is clearly the dominant system. In a 1 km run, this system is already providing approximately half the energy; in a marathon run it provides 98% or more.

Now that we can define fitness, we can move along to defining CrossFit, the study of increasing fitness.

What is Fitness - CrossFit Journal