CrossFit is a system that aims to prepare its trainees for any physical contingency. It trains everything from powerlifting to aerobic exercise, bodyweight/gymnastic and olympic weightlifting. They train for everything, to be prepared for anything. An example of a CrossFit “WOD” (Workout Of the Day) would be the Murph :
A timed 1-mile run, followed by 100 pullups, 200 pushups, 300 bodyweight squats, finished off by another 1-mile run.
As you can see this includes high intensity aerobic and endurance exercises. Its benefits include “increased body strength/endurance and mental toughness, minimizing overuse injuries because of exercise variety, time effectiveness, camaraderie and positive hormonal response because of high intensity/high volume exercise with minimal rest intervals.”
What I personally like about CrossFit is the variety of workouts and exercises and the different areas of fitness it covers. Not one workout is the same and I find that it brings a lot of novelty in the training as well as motivation. It has become popular especially with the CrossFit Games, in which you have concrete evidence that these benefits can be true. The athletes in the CrossFit Games are considered to be the fittest athletes in the world, from power to endurance and aerobic capacity, not to mention their incredible aesthetic shape. It sounds wonderful, however it violates almost every single law of training.
-The WOD’s violate the principle of individual differences, because not everyone will be able to do the workouts demanded. They have the same workout for everyone, no matter the level.
-It violates the principle of overload and compensation because the exercises are always different, meaning you are not consistent enough with the same workout to gradually improve on it. They are always “program hopping”.
– The SAID principle, Specific Adaptation to Imposed Demand, is ignored. The workouts are random so there is no foundational training that goes into more specific movements.
-Finally, all the CrossFit workouts are 100% intensity so it violates the GAS principle (General Adaptation Syndrome). We undergo shock, compensation and exhaustion so we must periodize the workout to account for that. And there is no deload, progression or light days in CrossFit.
As you can see, this workout system is basically a rebellious workout variation as it completely ignores most of the laws. The laws are set up for a reason, to keep your workout as safe and efficient as possible.
People that get injured in CrossFit is a common thing, having someone do 120 dips and pull-ups and then a 5×5 in the push jerk with max loads the day after can lead to serious problems on the shoulder joint. Having a workout with that much intensity done in a short amount of time with little to no rest can cause serious Rhabdomyolysis which is a popular CrossFit injury that refers to a breakdown of muscle tissue that eats to the release of muscle fiber into the blood and can cause kidney damage.
All of this is due to the “Game” mentality, the competition, it forces people to workout at maximum intensity as fast as possible, constantly. Also, most movements are done in the goal to be as quick as possible, such as the butterfly pull-up. Instead of just doing a regular pull-up with proper form they swing their whole body upwards in order to “do more in less time”, which doesn’t workout the targeted muscle to any significant degree. You would think it works well because of the impressive physiques of the participants in the CrossFit games but those are the elite athletes, the fittest in the world, that devoted most of their life to training. If you devoted most of your life to any way of training you would have the looks that follow too after a while. Therefore, it does not apply to everyone. If you start CrossFit with the hopes of looking like Rich Froning, you might be disappointed.
Unless your goal is to participate in the Games, I wouldn’t recommend CrossFit as your progression model. You can do athletic style training in a smarter way, and I would highly recommend you do so. Teaching everyone to perform basic barbell movements is a great thing that CrossFit has done, and we should adopt certain features from the training style, but certainly not all of it. Having the variety and novelty in its workouts definitely is a high motivational factor that can help push people to go workout and perform to the best of their abilities. Especially in all of the areas of fitness. So in that sense I can see why it is really appealing to most people. It gives you the idea of being an all around athlete, which many people tend to lack due to a higher importance on aesthetics.