In Rest Day/Theory

February 08, 2012

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Dr. Ken Gall examines the thermodynamics of CrossFit and asks 10 questions worth considering.

While I was an undergraduate research assistant, one of the graduate students in my lab wanted to show me a “thing on the computer” that you could use to “look up information.” I took a look at it, reluctantly, because this guy was always wasting my time with annoying things such as balloon animals and ballroom dancing.

When he showed me his little discovery, I laughed and told him it looked “useless” and I had no interest in wasting time on it. The year was 1994, I was at the University of Illinois, and the software he showed me was called Mosaic. For those of you unfamiliar with Mosaic, you may better recognize its second-generation name: Netscape. As it turns out, Web browsing and this “terrible annoyance” called the Internet have some use.

I missed the boat. CrossFit’s approach is the Mosaic/Netscape of fitness, and I’m not missing something big this time.



15 Comments on “Work, Power and the Science of CrossFit”


wrote …

First off great article I love math, although I am admittedly not very good at it, and I am a science nerd extraordinaire so this article was right up my alley.

My question is, would grouping athletes by a ratio of leg length, arm length and torso length create a better balance in a competitive setting?

I ask because you cant simply take height into account. My brother who is 3 inches shorter than I am has not only longer legs but also arms the length of a Gorilla. I am built with a torso that is far out of spec with my leg and arm length. Wouldn't this then mean in a ground to over head scenario (ie. wall balls, thruster, and clean and jerk) my brother would be outputting more power than myself. And before you say "well your torso makes you taller so you still have a larger distance to cover." know that me standing with my arms over my head next to my brother in the same position my brother is actually slightly taller than I am.


wrote …

Truck or Audi R8? Wonder why you picked the Audi R8 for the example :)


wrote …

Here is the main unsolved dilema in this article-
"if power generation is our measure and body type influences actual power output
greatly, we need some innovative ways to test for this that don’t bore people to death in watching a competition"
I'm afraid that as more competitions become televised, and as this sport continues to grow, TV ratings and money will naturally force the competition WOD's towards larger, more "physically impressive" athletes, risking the alienation of the vast majority of Crossfitters. I believe we are seeing this trend already wth the Spealler type athlete having trouble competing against physically larger competitors.
Hopefully, we can solve the aforementioned dilema and level the playing field.


wrote …

Interesting article, especially enjoyable as I took a study break as a current med school hopeful preparing for the Mcat in April to log in to the journal and this article was right on top. Its great to see the applications of physics and chem presented in regards to Crossfit as opposed to the study materials I've been reviewing. Time to finish up some review and hit a WOD.


wrote …

Dr. Gall,

Thank you. Your final endnotes are things I've been harping on for a while. Until we take each athlete in a given competition and take precise measurements of their limbs/dimensions to aid in the power equations, we don't truly know who the "fittest" is; that is if we in fact say that fitness is directly related to the amount of power output performed in an event.

Simply going off of time or weight moved isn't enough, but it is what we are stuck with at the moment. I'm sure there are programs out there capable of taking precise measurements from videos (i.e. total distance the barbell moved in a thruster) that could in real time then provide us with the power for the movement.

The problem of spectators still remains though as explaining that athlete X won the event (produced the most power) even though athlete Y finished 5 seconds faster is anti-climactic. Weight classes won't solve the problem, height classes won't solve the problem, nothing will really solve this problem in the current framework/mindset we have. The viewer/spectator will have to recognize/learn that the fastest time is not necessarily the most impressive performance, and until that becomes the norm, we're stuck.


replied to comment from Tony Leonardi

Tony, by physically impressive, did you mean Rich Froning at 5'8", Jason Khalipa at 5'9" or the huge Mikko Salo at 5'10"? Spealer, I love him, but at 5'5", is always going to be advantaged in some exercises and disadvantaged in others because of his larger variance from average size.


wrote …

Thanks for the well thought out article Dr. Gall!

Charles Poliquin ( and James FitzGerald ( take a lot of these issues into consideration in their PICP and OPT CCP coaching certifications. There is a division somewhere in the road here when discussing CrossFit as "weightlifting, gymnastics, and cardio" vs. CrossFit as "the sport of fitness." I am very interested in your writing, so please keep at it!



wrote …

Very interesting article. This is exactly why CF is so amazing and will never be stagnant, because we are always asking, exploring, and experimenting.

The demands of competing in the sport of fitness, aka the Games are definitely different than simply getting yourself into great shape. I'm currently pursuing the latter.

We have yet to find a better formula to maximize individual fitness that trying to do work quickly, aka, produce power. However, in a competition setting what matters most is task accomplishment. He or she that does the work/task the quickest is the winner, regardless of body weight, limb length, etc, etc.

Once again, interesting article. Thanks for getting me thinking.


Jonathan Gray wrote …

I've been craving a science based article. Good work.


wrote …

The point that anthropometric differences play as large a role in determining power and work capacity as load, distance and speed is well made.

The question of how we can standardise competition (in this case to make it spectator friendly) I believe has a simple answer, and it comes from the programming, not from the measurement.

Just as a larger athlete would usually excel in a strength based event, and a smaller athlete in a bodyweight based event (a generalisation, but an accurate one in most cases), athletes of certain heights/limb lengths/anthropometric ratios will be favoured by certain movements.

In the first two examples (larger vs smaller athlete), programming standardises body weight by including a mix of elements that would favour each body type. In a multi-event competition such as The Games, I would be very surprised if the programmers did not list 'balance of weightlifting/gymnastics' as one of their primary guidelines.

In the same way, competitions can be programmed to take into account anthropometric differences. Just as a balance of weightlifting/gymnastics negates the need for a weigh-in, a balance of movements favouring the extremes of anthropometry negates the need for separate power calculations for each athlete. Similar movements can still be programmed, with modifications to account for individual differences (as alluded to by Dr. Gall in his comparison of the thruster and the wall ball - in essence, the same exercise but favouring different people).

Glassman tells us “The magic is in the movement, the art is in the programming, the science is in the explanation, and the fun is in the community.” In this case, the science is in the programming.

Dan Williams
Range of Motion


wrote …

Great article!

I think it would be wise for Crossfit to program the games for the average body weight, limb length, etc, etc.

Gymnastics is for short people
Basketball is for tall people
sumo wrestling is for fat people



wrote …

Thanks for the comments, I really appreciate people having a look at my article. I agree on the thoughts regarding careful programming and the split between task oriented competitions and trying to be fit. In the end, I have to admit, one of the things I like the most about crossfit it that people of vastly different body type can compete side by side, even if small differences exist in power output. I also appreciate that crossfit is full of people who have a passion for perfection and finding ways to choose innovative task based workouts that are fun to watch, don't bias any particular body type, and require high power output, is a continual pursuit, and part of the excitement of a developing sport and daily fitness approach!

At the very minimum I hope my thoughts in this article at least inspire people to, as Pat said, ask, explore, and experiment. We are all fortunate to be part of something big here!


wrote …

Dr. Gall,

Have you seen the article from Catalyst Athletics' Performance Menu called "Getting Scaling Right: A systematic Method for CrossFit Porgramming" by Pierre Auge? I would be intersted to hear your analysis of it. It has become my bible for programming and scaling CF workouts to maximize power output for my athletes.

Fantastic article, love the science!


replied to comment from Tony Leonardi

In regards to Tony- That is what is going to happen when Reebok buys out Crossfit. Look at what it has done to football. Eventually everything will be run by corporation and the true at heart athletes trying to survive will be pushed out of the way. That is why I first fell in love with Crossfit. An average athlete can be so much more.


wrote …

Great article! I appreciate the mechanical and chemical reviews. These thoughts will continue to propel our institution further. Awesome!

However, with respect to the Games and finding the fittest person on the planet, I think that any given life or death scenario will not discriminate. "Charlie" does not care if you have long legs or short torso; all "Charlie" cares about is you dying.

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