"What Is Fitness?" Part 4: The Sickness-Wellness-Fitness Continuum

ByCrossFit October 2, 2021

In Part 4 of this six-part series on CrossFit’s definition of fitness, Seminar Staff Head Trainer Jenn Hunter-Marshall breaks down CrossFit’s fourth model of fitness: the sickness-wellness-fitness continuum. 

“This continuum represents your health,” Hunter-Marshall says during a Level 1 Certificate Course presented at CrossFit South Philly in early 2021, “so that fitness is just a state of super health.” 

We have observed that nearly every measurable value of health can be placed on a continuum that ranges from sickness to wellness to fitness. Though tougher to measure, we would even add mental health to this observation. 

Examples of such values include blood pressure, body-fat percentage, heart rate, and glycated hemoglobin (HbA1c) levels, among others. 

“The fittest will have all of their parameters or markers going in the direction of fit,” Hunter-Marshall explains.

Done right, fitness provides a great margin of protection against the ravages of time and disease. Where you find otherwise, examine the fitness protocol, especially diet. Fitness is and should be “super-wellness.” Sickness, wellness, and fitness are measures of the same entity.

“We don’t know what’s gonna happen in life,” Hunter-Marshall says. “Because life happens for all of us, and we have no control over it, but … there are certain things that we do have control over, and if we can use those things that we have control over to push us (to fitness), we’re creating the best line of defense for ourselves when something goes awry.”