The ideas from this article were originally written by the founder of CrossFit, Greg Glassman back in 2002. That article can be found HERE.
Why does CrossFit work better than just walking on a treadmill or alternating between weight machines? The answer lies in the way in which CrossFit integrates multiple metabolic pathways.
The three metabolic pathways are phosphagen, glycolytic, and oxidative. The phosphagen pathway encompasses movement less than 10 seconds in duration, for example bursting out of the blocks in a 100m dash. The glycolytic pathway incorporates movement lasting up to several minutes, like a 500m row, and the oxidative pathway is any movement that lasts longer than several minutes such as a half marathon.
The most optimal fitness results occur when an athlete incorporates all three metabolic pathways. Many, many sports neglects one or two of these pathways which diminishes fitness returns. This is why a regular routine of walking or running on a treadmill for 45 minutes does not get you as fit as you thought it would.
Additionally, this is why our CrossFit workouts vary in time duration. Each day the workout is a different time domain, ensuring that we can hit every metabolic pathway during the workout, and if not during the workout over the course of the week. Finally, this is why a coach might have you modify the movement or scale the weight to maintain the prescribed time domain and intensity.
The last page of the article linked above has a great graphic chart depicting the different metabolic pathways across many different sports. The next couple of weeks, the blog post will cover other elements of this article.