Check out this video courtesy of CrossFit by Overload then the brief discussion below.
As defined by Coach Glassman, CrossFitʼs founder, CrossFit is “constantly varied, functional movement, performed at high intensity.” Letʼs break that down a little bit.
CrossFit is Constantly Varied.
It is constantly varied in that it does not follow a routine. To look at a set of CrossFit workouts, you would see they are varied in the movements used, the combinations thereof, and in the duration of effort–and thus in the various manners by which the body produces energy.
CrossFit is Functional.
There are no single-joint, isolation, “body-building” movements here. CrossFit movements are those that are seen and used in real life. They are unrivaled in their ability to illicit power and all the positive effects that result from its production.
CrossFit is Intense.
There are no shortcuts or easy ways, just safe and proper instruction coupled with intensity. This is the land of results. Intensity, relative to each individual, is where all the positive effects of fitness reside. Some would rather read a magazine while riding slowly on a stationary bike. If that is you, there are plenty of gyms to go to (and there is still some benefit in doing so). Here though, we work, accepting discomfort as a necessary by-product, and thus we improve.
This just scratches the surface. If your interest is piqued, go here http://www.crossfit.com/cf-info/what-crossfit.html and let the exploring begin! CrossFitʼs main site has a wealth of information and resources.