“It’s a quantifiable approach to a finally well-defined notion of what fitness is. That is what CrossFit is,” CrossFit co-founder Greg Glassman says in defining the program he created and showing how it differs from every other exercise regimen out there.

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The CrossFit definition of fitness comes from three operational models explained in the Level 1 Training Guide (paid subscriber-only-access): balance in CrossFit’s 10 general physical skills, the hopper model of random physical challenges, and the balance of the three metabolic pathways.

According to Glassman, these ideas “eventually gave way to this understanding that fitness was work capacity measured across broad time and modal domains, and that indeed is fitness and is CrossFit.”

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Glassman emphasizes how different CrossFit is from other programs.

“CrossFit is the application of the fundamentals of Newtonian mechanics to human movement, something else that is kind of unique for us,”

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Moving beyond physics, CrossFit has also become a “social phenomenon” with a tightly knit community. A CrossFit gym is unlike any other gym.
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At the end of the video, Glassman fields tough questions from the audience and succinctly sums up CrossFit with some familiar words: “constantly varied, high-intensity functional movement.”