In Audio, CrossFit, Videos

March 13, 2009

Video Article

Pat Sherwood presented the What is CrossFit lecture at the Maine State Police Criminal Justice Academy on June 19th, 2008. This video is the segment on intensity and its role in fitness.

Intensity, as we define it, is exactly equal to average power (force x distance / time). In other words, how much real work did you do and in what time period? The greater the average power, the greater the intensity. This makes it a measurable fact, not a debatable opinion.

Intensity and average power are the variable most commonly associate with optimizing favorable results. Whatever you want from exercise comes faster with intensity. It’s not volume or duration or heartrate or even discomfort. Do more work in less time (without overdoing it), and you’ll get fitter faster.

If you’ve been following the CrossFit site for a while, this isn’t new material. It is, however, the aspect of CrossFit that drives our success as much as any other single factor. And, in all domains, it’s always good to return to the fundamentals on a regular basis.

6min 39sec

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36 Comments on “Intensity (and its Role in Fitness)”


wrote …

Sherwood's so hot right now....


Ned Ferguson wrote …

"Intensity is exactly equal to power."

So intensity is an absolute measurement and does not vary from person to person? I mean sure, power output will vary from person to person but the effort will not be the same. I don't get it, because I am of the mind that what is intense for me may not be intense for you and vise versa. Therefore intensity is more equal to effort. It seems that the statement should be modified to "Intensity means getting near to an individual's maximal power output." Please clarify. Maybe I just misunderstand.


Chris Walls wrote …

Power is equal to intensity in that having a higher power output over time is more intense. Doing Fran by breaking everything up will be less intense then doing it unbroken with no rest because the overall output is higher. Sure the work is the same, but it's work/time that gets you power.


wrote …

I would like to see a definition for "effort" since clearly effort and intensity are not the same thing as per this definition.


wrote …


Intensity is not equal to effort because you can't measure how hard someone is trying. What you can measure is how much work was done i.e.; the weight of the load, the weight of the athlete, the total distance they were moved, and how long it took. This gives a measurement of foot/pounds per minute indicating power output. That's why the question is "what's your Fran time?", and not "how hard did you try on Fran?".

Hope this helps.


Thanks for the replies, but I cannot get away from the fact that “Intensity=Power” just does not compute as a straight logical calculation. I do not see how it cannot be relative. For example, consider the “Little Engine that Could.” The large locomotive routinely pulls a large load up the big hill with no big tax to his “system.” One day the large locomotive breaks down and the town has to rely on the Little Engine to get the cars up the big hill. We all know the story. Only through valiant effort does the Little Engine barely make it up the big hill with the large load, and only after stopping and appearing to fail. Are you seriously going to tell the Little Engine at the top, “I just wish you had showed more intensity”? Is it a compelling argument to say that the large locomotive’s regular “workout” is more intense than the Little Engine’s valiant effort (even though the actual power output by the Little Engine was clearly less)?

Likewise, are you going to tell the client after finishing Fran in 9 minutes while they puke in the bucket that their workout is not intense unless they are sub 4 minutes? Perhaps you cannot measure effort well, but you can certainly judge it empirically. I am not trying to be argumentative; I just truly don’t get it.


Ned Ferguson wrote …

P.S. I am not trying to say that “Intensity=Effort” exactly either. I was only trying to make the definition more workable by tying it to maximal power output *for that individual* as opposed to absolute power output.


wrote …

It seems to me it IS tied to the individual.

That was a supreme EFFORT, but using as much power as you did over nine minutes, compared to someone who does the same amount of work in 3 minutes is not as INTENSE an expenditure of energy.

Some individuals require significantly more effort to generate that intensity than others.

Or... what is the workout that will impact an individual MORE...

Fran in 3 minutes or Fran in 30 minutes?

For me, Fran in 30 is easy(not intense) but Fran in 3 is currently not doable(so intense it results in system failure).


wrote …

Perhaps you could change the defintion of intesity to: intensity = individual effort rather then power.If power is force x distance / time then perhaps you could describe effort as the practical application of force. Coach talked about it once in a video. If you are moving as fast as you can with good technique using the 80/20 rule you are operating at maximum individual effort and therfore with maximum intensity.
Power should still be the ultimate goal of any fitness program but individual effort is a better measure of intensity and improvement over time and day to day. For instance an athlete may not be able to produce a sub 2 min fran every time the work out comes up, but as long as they are moving as fast as they can on any given day with good technique then they are operating at a high level of intensity regardless of load or time.


replied to comment from Ned Ferguson

I assumed that intensity relative to one's own maximum potential output was implicit.


wrote …

Obviously power and intensity are linked and the reality with crossfit is that it doesn't help for us to think about intensity as a relative statement. If that were the case we could not measure and quantify it. Why is it important to measure and quantify? Because that's the only way we can improve as athletes. The only way we are getting fitter is by getting more intense. That could mean lifting more weight or lifting the same weight over a greater distance and/or doing it in less time...but unless we are continually pushing ourselves to increase the average power (intensity) then we are not going to get more fit.

Think of intensity as crossfit defines it like you would think of intelligence. If you and I take a test and I try harder than you (more effort), but still score less than you on the test does that make me smarter than you?? was a great effort for me, but you are still the smarter one. This is the same as the fact that you are capable of more intensity if your Fran time is quicker than mine.


wrote …

Intensity = power means that is how intensity is measured by ex physiologists and CF. Power is force times distance divided by time. IOW, to measure intensity, one needs to know what weight you moved, how far, and how long it took. That provides a measure of intensity.

What effort may be required by me, you, or Speal, to generate that much power (intesity) is an altogether different issue. If Speal does Fran in my time, 5 minutes, it will not be a very great effort on his part (relatively low intensity), and it will not generate favorable adaptations for him at the same rate as a more intense effort would.

The key is if you want to get fit as rapidly as possible, build intensity (greater power output) into your workouts. How much intensity? As much as you can. More intensity relative to your max intensity = most desired adaptation to the training stimulus.

Your client's 9 minute Fran may or may not be evidence of great relative intensity - generally, however, Pukie is evidence of great intensity (plenty of caveats there).



wrote …

The problem that you may be having in understanding the relation that is being used more than likely stems from the way these two words are used on a day to day basis. Power and intensity are terms that usually exist in two different domains, one is the general populace, and the other is from a physics perspective. Somewhat contrary to what was stated in the video, intensity and power are not identical terms. Intensity is just the result of power divided by area that the force is acting on. For all sakes and purpose though, the division through by area is not necessarily relevant for a conversation on excercise. Objectively, doing a 4-minute fran IS more intense than doing a 9-minute fran, regardless of how you feel. An identicial amount of work completed in a lower amount of time is, by definition, more powerful. Assuming that how tired you are is a factor of your intensity via output through a workout is where you're getting confused. From a LAYMAN'S usage of the term intensity though, your 9-minute fran very well may have been way more "intense" than someones 4-minute fran, but you have to keep in mind that the usage of "intensity" that you have now switched to is not one that is quantifiable, because as someone previously said you can't quantify the human emotion of exhaustion (epic run on sentence, apologies). It's just a matter of two different definitions for the same term here that is the confusing factor. Hope that helps.


wrote …

In the FWIW category ...

Fran in 2.05 at 5 foot 4 inches and 135 pound body weight,
or Fran in 2.35 5 ft 9 in and 170 pound body weight,
or Fran in 4.05 at 7 feet tall and 250 pounds, all approx .45 hp, or about 235 ft pounds/second of power. Half a horse power - do you think that's intense for a human being? Paul


wrote …

also, for a better context for Pat's presentation, check this vid out from the 'exercises and demos' section:


wrote …


What people tend to forget about calculating work is that it's nowhere near as black-and-white as a few simple calculations of "bar weighing x lbs moves up by y-feet". Gravity, the tension of the skeletal system, and statics are all huge players in actually getting anything close to an approximate value for the work done during something like fran. For instance, it takes a significant amount of work enacted against gravity to lower a barbell back down from the top of a thruster in a controlled fashion. Likewise, calculating the arc length that the body travels during a kipping pullup would be a nightmare. Truth be told, and this is crazy to think about, an actual approximation of the amount of work being done would probably be significantly higher than what you have. Physics applied to biological systems is often a beast of a task to handle.

The face that the number is hovering somewhere around half a horsepower really is impressive to think about though.


wrote …

Adam, There's no doubting what you say wrt precision in calculation. For the circumstance we face, I think the wt*dist/time is meaningful. The arc distance of the pu, for example, is not relevant, and could be regarded as waste for example, and the HP used to lower a weight either could or could not be measured, but would it provide more insight into an athlete's output? Probably only has meaning if trying to precisely compare the HP of two different sized athletes, which CF only does for purpose of entertainment.

The power calculation - each trainee's relative power, for example, or the average power of a company of troops - is sufficiently precise to allow it to inform the CF model of fitness. As a basis for creating workouts - workouts that allow athletes to generate more power being significant to the increase in fitness - wt*dist/time works.

That said, I think your point goes to another issue - the sport of fitness. No one wants to watch folks work out and then wait for a power calculation to see who won. They want to watch the event anticipating who finishes first. Who moved the object the required distance in the least time. As they say, "every second counts." Paul


wrote …

It seems to me that a relative power output value taking into account body mass might be helpful, as in Watts/kg/min. Who is fitter? A 300 pound person deadlifting 550 or a 190 pound person deadlifting 500? My money is on the 190 pounder, and that's my personal opinion. Given CF's emphasis on strength-to-weight ratio (muscle-ups anyone?), it seems there might be a place for power-to-weight as well. For example, the power-to-body mass numbers coming from some of the less massive CrossFitters (like Spealler) are higher vis a vis the external load than those for bigger individuals clocking in at the same workout times. Does this make them fitter? I think you could argue that it does, technically. Now, if you find yourself wrestling a black bear in the woods high absolute max power output might be more advantageous than high power-to-weight...
I agree with what was said about the sport of fitness - the clock is the motivator for the petite and massive athlete alike, as well as the entertainment for the crowd. Just some academic thoughts for y'all to chew on.


wrote …

Liked the video...Pat's always easy to listen to and learn from. He's funny, blunt and straight to the point


replied to comment from calen hall

First of all, I'd like to say that a roller blade - hula hoop WOD sounds awesome!

On another note, Calen, as to your point in measuring power output relative to body mass, I agree that it's interesting from an academic standpoint, but it can break down as a broad, objective measure of performance. For example, a taller or heavier athlete doing Fran may put out more power than a a lighter athlete in the same (or even longer) time because they are moving a heavier bodyweight and through a longer distance, if they have longer arms/legs. However, the lighter athlete may be performing with a better power/external mass ratio based on the 95 lb. weight lifted but not accounting for body weight. So, which one is better? Depends on what you're trying to measure. These relative measure based on body weight and size are hard to use as performance indicators as we get into more specific situations. There are ways to interpret them to measure the same performances in different ways.

Additionally, there is the question of time and weight. Let's look at 2 extremes.
Take the King Kong workout for example. Most athletes can't even complete that WOD, so their power output is essentially zero for the task.

At the other extreme, if we have a 10 mile run, a lighter athlete may be able to complete the run so much faster than a heavier athlete, that even though they moved less mass over those 5 miles, they had a much higher total power output because of their lower time.

I'm just making the point that ways of measuring power output can become less consistent and more manipulatable once we start taking into account more variables and measuring across more extreme time and modal domains. Crossfit's definition, while not perfect, attempts to stick to only what can be easily measured, and in time and modal domains that are inclusive to most trained CF athletes. And I bet you'll find that those numbers correlate well with the athletes' real capabilities on a pound for pound basis as well.



wrote …

How do isometric exercises factor into the intensity question?

For example, I've been working on a planche, front lever, back lever, and handstands. All of which are static holds, but require a great deal of effort. It seems using the W x D / T equation would show very little intensity and doesn't factor in leverage. I assume that static holds don't work with this equation because they are not "functional movements."


wrote …

Vrandon, as I understand these things, your last bit is correct. ACFer who does holds should do so as a means to improve functional movements, thus improving his/her work capacity across broad time and modal domains. The Cf premise is that holds alone would not result in the most desired physiological adaptations, due to their by definition lack of intensity. Paul


Ned Ferguson wrote …

Adam Campbell,

Your post does help, thanks. I think I am just going to have to compartmentalize the scientific definition vs. the common vernacular. After all, if we are going to say that CrossFit is "constantly varied functional movements performed at high intensity" and in the same breath say that "anyone can do Crossfit, just scale the WODs", we must have a more tenable definition of "intensity" in there somewhere.


replied to comment from Apollo Swabbie

So is there a different equation for static holds? For example, holding a planche is an extremely intense exercise and requires a high degree of strength, but using the traditional I=F x D / t equation wouldn't show a high power output and also doesn't take into account if you are doing a tuck planche or full planche, which is using the same amount of body weight, but the difference in leverage requires much more strength.

Another factor to take into account is that the longer you hold the planche, the higher your power output would be. This is the opposite of the traditional equation where your power output would increase if you could decrease the amount of time required to perform the same amount of work.

I'm not sure if I'm getting my thoughts across correctly, but I hope that makes sense.


replied to comment from Brandon Roth


Statics is a tricky question because technically there is no work being done. For example, if you were to place both hands against a wall in your living room, and than proceed to push with all your strength, the wall still would not move and by definition no "work" would have been done. Now are you exerting a force? Without a doubt, but you then have to realize that you and the wall, disregarding other irrelevant variables, are forming what is termed a "closed system". While you are exerting a force on the wall, the wall proceeds to exert a force on you which is exactly equal and opposite, no movement occurs, and hence no work occurs.

The concept is identical to a planche, except now you have created a closed system between the earth (more precisely its gravitational pull) and yourself. Your body is straining because it is attempting to withstand the downward force of gravity and produce an equal and opposite force, creating a situation where your body undergoes no movement. It's a quick jump then to realize that work in this scenario is also meaningless. You have just placed D=0 into the equation f*d/t, making the equation useless. What does this mean? Power, intensity, and work are all concepts which do not apply for static movements, or in that matter for really any Statics situation in which you have a net force summing to 0.

While very useful for some things, the laws of physics often rarely exhibit useful analogues to an excercise/sports science domain. Simple understandings of things like force and work are very useful in the right context, but once you start scratching past the surface you quickly find that ridiculous degrees of advanced mathematics are necessary to analyze human movement on a precise and quantified level. Don't get too caught up in the wordplay and just hit the wod's hard, you don't need a doctorate to know when you're pushing yourself physically.


wrote …


Well said, and I completely agree, I just always find it interesting to see what an accurate calculation of the work output done during a WOD would actually show.


replied to comment from Adam Campbell

Thanks Adam, that was a great response. I think my take-home message is that although static exercises are intense, the Power Generated formula is only applicable to movement and not static exercises.


Joseph Alexander wrote …

Much love to Pat Sherwood!



Ned Ferguson wrote …

I think I finally figured out a way to keep this straight in my mind. The relative term is not “intensity” but “high”.

1. “High” intensity / power output is relative for a particular athlete.
2. Most CrossFit workouts are high intensity relative to what the athlete has done before or the typical globo gym/bodybuilder type workout.
3. Some Crossfitters are more intense than others.

It really is that simple. I don’t know why I didn’t see it before. I think it was Pat's emphasis on the question of "Was your workout intense?" Well heck yeah my workouts are intense. By definition almost any workout produces *some* intensity (power).


replied to comment from Adam Campbell

Adam, #25 - so would I, it would be really interesting to see that stat. Paul


wrote …

You guys are bigg freakin dorks
Go to your box lift some big weights, a long way, really fast.
Tomorrow lift a little more, a little further, a little faster!


wrote …

The three bar equal sign (≡)means "is defined as." The regular equal sign (=) means "is (exactly) equal to;" the exactly is implicit. The squiggly one (≈) means "is approximately equal to." I hate to be a dork, but if you're gonna be precise, you might as well be correct.


wrote …

Not sure I'm seeing the discrepancy Samuel.


replied to comment from DEANE YOLANDA

Deane, I take offense to the term "bigg freakin dorks." Sounds like someone who got hooked on phonics but cannot spell. Much prefer 'Massive Geek'. A little sensitivity, please. Paul


Adam Kruppa wrote …





replied to comment from Ned Ferguson

What you are failing to realize is a result that permeates society right now? Why should a fat slob learning to do fran be able to be as intense as a STUD pushing Fran sub 4? They aren't. They can't push intensity the same. It could have been "intense for them" but not intense period.

Its the same as when Kobe dunks over someone you go WHOA! Because it was intense. When a Lady collegiate player puts in a lay up and you yawn and change the channel do you care that she says, "well I can't get intense like Kobe...I'm a girl"? No. Just because she can't do something doesn't take away from the fact that one is INTENSE. One is POWER. The other is a shadow. It could subjectively be intense, but not on the same level.

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