Revisiting CrossFit’s Definition of Fitness

14 years since it was first published, CrossFit’s definition of fitness remains the most comprehensive and accurate.

Time for a little self evaluation: Are you fit? After all, you work out three to five times per week and have been doing so for more than a year. You do regular weight and cardiovascular training, and you follow a healthy diet. Considering the obesity epidemic, it would seem the short answer is yes, you are fit.

But before we can accept this answer we must first ask another question: How is fitness defined?

If we limit the definition of fitness to one area, are we really defining it? [Photo credit: Cara Kobernik]

What Defines Fitness?

The popular press has had a tendency to focus on endurance athletes when attempting to define fitness. It is likely that individuals with a high degree of aerobic capacity would be considered fit. But was six-time Ironman Triathlon World Champion Mark Allen truly “the fittest man on earth?” What title should we bestow on an Olympic gold medal decathlete such as Dan O’Brien? Both of these athletes possess tremendous amounts of aerobic capacity, but it would be safe to assume that O’Brien would fair better on tests of strength and power. After all, a decathlete must sprint, jump, and throw as well as run. There is no easy answer in comparisons like this, which demonstrates the limits of this definition.

The fitness community isn’t much help, either. If one scours the publications of the American College of Sports Medicine (ACSM) or the National Strength and Conditioning Association (NSCA), they will be left wanting for help. Neither of these institutions, both of which are looked to as industry standard-bearers, even attempt a working definition of fitness.

What elements should the definition of fitness include? Common sense would list things like strength, speed, power, and coordination. Let’s say you can bench press 400lb, squat 500lb, and deadlift three times your body weight. Does this mean you are fit? What if you can run a sub-seven-minute mile, do 200 sit ups without pause, and execute 100 perfect hand-release push ups. Are you fit?

CrossFit’s Fitness Standards

CrossFit may be considered contrarian in their view points, but they remain the only organization who has attempted to put forth a comprehensive definition of fitness. Their definition is broken down into four standards that at least warrant consideration.

General Physical Skills

In order to be considered fit, CrossFit asserts that an individual must demonstrate competency in the following areas:

  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 pat- terns 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.

Measurable Wellness

In order to be considered fit, an individual must demonstrate that they are otherwise healthy. Health is represented as a continuum ranging from sickness to wellness, which can be quantified by values for things such as blood lipid profiles, body composition, blood pressure, bone density as well as cognitive health. If an individual is “fit” they will have achieved a sort of super wellness.

Life Fitness

In order to be considered fit, an individual must demonstrate “life fitness.” That means they should be prepared to perform well in all situations, including the unknown and the unknowable. Combat, survival, and sports are the ultimate tests of this sort of general physical preparation. Real-world fitness doesn’t involve traditional sets, reps and periodization schemes because life is not that predictable. That unpredictability means that traditional fitness routines are of limited value in meansuring actual, functional fitness.

Energy Systems

In order to be considered fit, an individual must demonstrate sufficient development of all three metabolic pathways: phosphocreatine, glycolytic and aerobic.

  • The phosphocreatine (PCr or ATP-PC) pathway is the predominant energy system in activities lasting less then 10 seconds. This includes very explosive and short duration exercises such as 10m sprints, 1-rep maximum lifts, jumping, and throwing.
  • The glycolytic pathway is the predominant energy system for activities lasting between 30 seconds and 2-3 minutes. This includes exercises such as 400m and 800m sprints and higher-volume weightlifting.
  • The aerobic pathway is the predominant energy system for activities lasting 5 minutes or longer. This includes longer distance running, biking, swimming, and rowing.

Focusing on the development of one system at the expense of the other two will necessarily limit your overall fitness potential.

The Purpose of CrossFit’s Definition

The first objective of this definition of fitness is to be broad, general and inclusive. Specialization, while appropriate for some athletes, often leaves one unprepared for the rigors of combat, survival, sports, and life in general. There is very little in the realm of fitness that would not ultimately fall under the umbrella of this definition.

The second objective of this definition is to show that measurements of wellness—blood pressure, body fat, blood lipid profiles, bone density and muscle mass—can be placed on a curve between sickness and wellness. If fitness is approached the right way, these markers can be improved, and one can avoid many of the ailments created by the modern lifestyle.

The third objective of this definition focuses on breadth and depth of performance. This is ultimately quantified by incorporating the elements of time, power, and energy systems utilized. By focusing on average power output (work divided by time), fitness can be objectively measured. The goal is to develop each energy system using interval-based metabolic conditioning. This allows an individual to maximize their aerobic and anaerobic pathways without sacrifice.

How Can You Become Fit?

Now that we have a potential working definition of fitness, it would seem logical to explore how one can achieve this. According to CrossFit, the goal is to shape athletes that are equal parts gymnast, Olympic weightlifter, and multi-modal sprinter. In order to accomplish this, we must implement a strength and conditioning program that combines high-intensity interval training with a solid foundation in body weight exercises and a proficiency in both Olympic and power lifting. Of course, nutrition is essential to this process as well, and individuals are encouraged to follow either a paleo-style or zone-style diet to maximize the benefits of their training regimen.

The definition of fitness provided by CrossFit is universally scalable, applicable, and irreducible. It is intended to help the young and old, the underweight and overweight, the healthy and the sick. Although there will be differing manifestations, the needs and goals of all individuals will differ by degree, not kind. A competitive athlete or a healthy senior, a bodybuilder or a competitive weightlifter, all want basically the same things.

This definition of fitness, much like CrossFit, may seem contrarian if not controversial. But it does provide us a starting point for dissecting what has otherwise been an elusive term. Only time will tell if it becomes the accepted as the working definition or whether it gets replaced by something better still. For now, it will have to do.

Any training system is only as good as its application:

The Only Variable That Matters

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