The Ten General Physical Skills

Why CrossFit Looks the Way It Does, Part 2

Part 1 covered the definition: constantly varied, high intensity, functional movement. That explains how CrossFit trains. It doesn't answer a more basic question underneath all of it.

What is fitness, actually?

Everyone uses the word. Almost nobody can define it in a way that holds up. Glassman ran into the same problem early on and went looking for an existing definition he could just borrow. The American College of Sports Medicine had one. It ran several hundred words and read like a committee had passed a hat around and everyone threw in a word they liked: vitality, wellbeing, sense of self, energy. By that definition, someone running on three energy drinks and no sleep has "energy," so they're fit. That's not a definition. That's nothing.

If fitness matters, and it does, it needs to be something you can actually measure. Not vibes. Numbers. So instead of one definition, Glassman built three different models, each one a different way of asking the same question: how do you know if someone is fit? Here's the first.

The Ten General Physical Skills

The first model breaks fitness into ten measurable skills:

• Cardiorespiratory endurance

• Stamina

• Strength

• Flexibility

• Power

• Speed

• Coordination

• Agility

• Balance

• Accuracy

Split those ten in half and something interesting shows up. The first four, endurance, stamina, strength, and flexibility, are what Glassman calls organic adaptations. They show up as an actual physical change in your tissue. You could biopsy the difference.

"These first four adaptations occur within the body tissues, and we can measure those changes. The last four happen between the ears. The adaptation is within the brain."

Coordination, agility, balance, and accuracy are neurological. Nothing in your muscle tissue changes. What changes is how your nervous system controls the movement. Power and speed sit in the middle, part tissue, part wiring.

Most gyms only train the first half. Get stronger, get more conditioned, done. But if you never work on balance, accuracy, or coordination, you're not actually fit by this model, you're just strong and tired in a straight line. That's a real part of why a CrossFit class has you balancing on a box, throwing a medicine ball at a target, or learning a new gymnastics skill. Those aren't filler. They're the other half of the ten skills nobody else is training.

That's one way to measure fitness. Next up is a completely different one, and it's the one that should actually change how you train.

Source: Greg Glassman, "The Purpose of CrossFit: Part 1"