Tired of idiots on here wrote:
"Core" training, the philosophy that the muscles of the torso somehow need special attention and should be trained by rules different than the ones that apply to every other muscle in the body, is a 100% pure marketing gimmick that became popular in the early 2000s as a result of shit being sold on late night TV infomercials and the like that promised people that balancing on stability balls was the new best way to get a 6-pack.
Bullshit, and you have to be either 12 years old or a fucking idiot to think core training started with TV marketing. If you're ignorant enough to ignore decades of solid evidence, you're a total waste of protoplasm.
For sure, there's a lot of stupid cross fitters out there that think that six-pack abs will solve their never being able to get laid problem, but just because some stupid people think a strong core will get them laid doesn't mean a strong core is a marketing gimmick. Mousolinni made the trains run on time, that doesn't mean the trains running on time is a bad thing.
Even a minimal amount of research turns up tons of evidence that a stable core enables a more energy efficient stride. There is energy loss in the hips if they are allowed to move forward during the push-off. Go back to any reputable training material dating back as far the 60's and you'll find untold number of coaches and physiologists explaining the principle. You can even find slo-mo videos of the effect. I got lectured about a firm core for faster running in the early 70's, in a town where TV went to a test pattern late at night. If you think core training is something new it's time to leave mama's basement.
So is cross fit a worthless gimmick? Sure. Did cross fit and TV marketing create the "core training" theory, no fucking way.