Chalk Talk: Fundamentals from the CrossFit Journal & Beyond: What Is Fitness? The 10 Physical Skills

‍Series introduction: Chalk Talk is where we go back to the source: the CrossFit Journal articles, lectures and foundational texts that shaped the methodology you're training under every day at Chalk Dog. Some of this content is decades old and still as relevant now as the day it was published.

The Idea

Back in 2002, CrossFit founder Greg Glassman published "What Is Fitness?" in the CrossFit Journal, one of the most referenced articles in the history of the methodology. The premise was simple but radical at the time: fitness isn't one thing. It's ten things. And if you're ignoring any of them, you have a gap.

Those ten skills are:

1. Cardiovascular/respiratory endurance: your body's ability to gather, process and deliver oxygen
2. Stamina: your body's ability to process, deliver, store and utilize energy
3. Strength: the ability of a muscle or group of muscles to apply force
4. Flexibility: the ability to maximize range of motion at a given joint
5. Power: the ability to apply maximum force in minimum time
6. Speed: the ability to minimize the cycle time of a repeated movement
7. Coordination: the ability to combine several distinct movement patterns into one fluid movement
8. Agility: the ability to minimize transition time from one movement pattern to another
9. Balance: the ability to control your center of gravity relative to your base of support
10. Accuracy: the ability to control movement in a given direction or at a given intensity

The framework comes from coaches Jim Cawley and Bruce Evans of Dynamax, and it's been the backbone of CrossFit's definition of fitness ever since.

What This Means in Practice

The tricky part: not all ten skills are developed the same way.

Endurance, stamina, strength and flexibility improve through training, meaning there's a measurable physical change happening in your body's tissues. You're building muscle, expanding lung capacity, increasing tendon resilience.

Coordination, agility, balance and accuracy improve through practice, meaning the adaptation is neurological. Your nervous system is learning new patterns. You're not just getting stronger; you're getting smarter about how you move.

Power and speed sit in both categories. They respond to training and practice, which is part of why developing them takes such a well-rounded approach.

The takeaway: showing up and going heavy isn't enough. Grinding cardio isn't enough. True fitness requires all ten, developed intentionally.

3 Key Takeaways

1. You are as fit as your weakest skill. CrossFit's definition of fitness doesn't grade on a curve. A gap in any one of the ten skills is a gap in your overall fitness, full stop. The athlete who is strong but can't coordinate a clean, or who has great endurance but no power, is not fully fit. This is what drives the constantly varied approach: we're filling gaps, not doubling down on strengths.

2. Some things you train. Some things you practice. Understanding the difference changes how you approach skill work. Kipping pull-ups, double unders and barbell cycling: these aren't just "movements." They're neurological adaptations. They require patience, repetition and deliberate practice. Don't get frustrated when more effort doesn't automatically mean more progress. What moves the needle is deliberate practice: correct reps, drills and focused attention on the motor pattern. Repeating a fault doesn't build the skill, it just makes the fault more automatic.

3. CrossFit's specialty is not specializing. This is straight from Glassman's original article, and it still resonates. Every specialized athlete, the marathoner, the powerlifter, the weekend warrior cyclist, excels at something and pays for it somewhere else. CrossFit's goal is broad, general, inclusive fitness. Not the best at any one thing, but capable across all of them.

It Comes Down to What Works

CrossFit is not chasing trends. I've heard it said that if shake weights and spinning in circles produced measurable results, CrossFit would program them. That's not a joke about being weird. It's a statement about the methodology's relationship with effectiveness.

The ten physical skills exist because they are measurable, trainable and transferable to real life. They aren't based on what looks good on social media or avoiding movements that might be intimidating. They're based on what actually makes people more capable in the gym, at work, at home and as they age.

That's why this framework drives our programming at Chalk Dog. Not because it's CrossFit doctrine, but because it works.

Read the CrossFit Journal article this post is based on: "What Is Fitness?"

Want to go deeper? The full "What Is Fitness?" lecture series is available on CrossFit.com and covers the hopper model, metabolic pathways and how CrossFit defines health, not just fitness. https://library.crossfit.com/free/pdf/CFJ-trial.pdf