why high intensity

In part 1 of this blog last week, we defined Crossfit as “constantly varied functional movements, performed at high intensity”.  I used to example of a burpee and an L-sit.   I talked about the very real life function of a burpee and being able to get yourself back up off the ground after you fall. Coincidentally, I also received an email a couple of days later from one of my Fit Over 50 members who had fallen doing yard work and was thankful for being able to get back up in that situation. Functional indeed!  I went on in the blog to talk about the L-sit. While it isn’t immediately functional, it does help to build the musculature that supports our mid-line which is a must in any functional movement. 


This week I want to talk about the “high intensity” part of that and how we define that. I will link below to the article in the Crossfit Journal entitled “Defining Crossfit Part 2: Intensity”. I’ll try to expand and simplify it here but I encourage you to take the quick minute to read the article direct from its source as well. 


When we hear the words “high intensity”, what comes to mind?  Elevated heart rate?  Sweating?  Puking?  Laid out on the floor after?  There are problems with these simple things as they relate to intensity. For example, as they mention in the article, an elevated heart rate does not necessarily mean we are getting more fit. Someone can have an elevated heart rate because they are nervous. The same could be said for sweating. Those are not measurable and repeatable values. They will differ from day to day. Sleep, nutrition, recovery, time of day, etc are all things that would affect those things and act as variables. 

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Crossfit has made it scientifically possible to “measure our fitness” by using simple physics principles. I have talked about them before. They are “force”, “distance” and “time”. Simply put, force multiplied by distance is equal to work. Let’s look at the burpee again. The “force” is our body acting against gravity. Our body weight. The “distance” is essentially how tall we are. We are laid flat on the ground and our body travels to a standing and extended position. We have accomplished “work” by applying force (moving a mass) over a distance (from laying to standing). Now we need to bring our third principle into play; “time”.  If we accomplish work very slowly, the related intensity is low. If it takes us five minutes to complete 20 burpees, we have hardly broke a sweat. However, if we complete that same amount of work (20 burpees) in one minute, the intensity is very high. We define this as “power output”.  We produced force through a distance and did it quickly. We can repeat this test tomorrow, next week and next month and produce scientific data to track our progress in fitness. 


In any given class your coach will go over “movement standards” before the workout.  Your coach is not doing this so the score wrote on the board is accurate compared to everyone else. Your coach is going over movement standards because we want you to be able to see and track progress with proof!  I have used this example in my classes before. Wall balls; a squat where hip crease passes below parallel with knee, a given weight ball is thrown to a given height target. If any of those things change, so has the work being performed. We don’t need to do a full depth squat to chuck the ball to its target. We don’t need to keep hitting that same target height. But how then can we repeat that effort in the future if we do not?  Less squat depth is less distance travelled. Less height on the ball is less force applied. Both are less work being performed. Truth is, unless you are doing Crossfit “as a sport” (and very, very few of us are) movements standards make no difference to your score. They do however make all the difference in the world to your “power output”.  Doing 100 half reps or 50 full reps will get you the intensity. 


Having defined “power output” and how we can scientifically and repeatably measure results, we can then look at intensity. “Intensity needs to be appropriate to the individuals physical and psychological tolerances.”  This means that intensity is going to look different for everyone. As a coach, one of the things that hurts my little heart is seeing people “shake their head” disapprovingly at themselves in a workout. For whatever reason it might be, the person feels their efforts are not stacking up.  It might sound like a cliche thing, but I want you to be proud of your efforts or learn from your efforts. Never be disappointed in your efforts. Having bad technique on clean twenty-three in a twenty-four rep clean cluster is not something to shake your head about. You have found your technical limit and now you know where you have to really start with the “intensity”.  The person who has 50 pounds more loaded on the barbell and makes them all look easy and pretty is not working at the same “intensity” and therefore not improving as much as you.  Having seven other people in class get off the rower before you is not something to shake your head at if you are working at “high intensity” for where you are at physically and psychologically.  You are getting results. Results that we can measure and track. 


So there we have it. What we are doing in Crossfit is not a hypothetical. It is not finding potential. We are summarizing real scientific data. Power output which creates a result that we can test, track and retest. That is why we have movement standards and that is why we strive for high intensity. It gets results. It’s in the data!


-Link to the full article in the Crossfit Journal below-

https://www.crossfit.com/essentials/defining-crossfit-part-2-intensity