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Fitness Theory and Practice. CrossFit's rationale & foundations. Who is fit? What is fitness?

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Old 12-03-2015, 10:27 AM   #1
Dane Thomas
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Redefining the relationship between Power and Intensity

The terms "force", "work", "distance", "time", "power", "area", and "intensity" all have well-defined meanings within the field of physics, and the relationships between these terms are precisely understood. Power = Work / Time, and Intensity = Power / Area (where the area is an imagined surface that is perpendicular to the direction of propagation of the energy)

When writing for a more general audience there is a natural temptation to descend from these precise usages to more colloquial definitions. I do not, however, feel that this makes it accurate to claim that in the field of human performance "...power is the definition of intensity...", or that "...intensity is defined as power.". I can memorize those phrases to get a better grade on a certification test, but that does not make them factually correct. Likewise, the fact that the phrases came directly from Coach Glassman in an article published in 2002 and have been repeated by countless other since then also does not make them any more scientifically accurate.

It seems to me that a program that is empirically driven, clinically tested, and community-developed, with an open-source charter that makes co-developers out of participating coaches, athletes, and trainers through a spontaneous and collaborative online community should welcome a discussion on this topic. Doing so could improve the general level of understanding and consensus, and potentially enhance something that is already very good. Think of it as a way of chasing intellectual virtuosity.

Please be assured that I understand and agree with the spirit of the point being made by the phrases. I just think that making the point while respecting the terms in question would make the argument more sound.

I think that it would be more accurate (yet still understandable and meaningful) to say that power is directly correlated with intensity, which in turn has been linked to nearly every positive aspect of fitness.

Anybody else out there agree? Is it more laudable to preserve dogma for dogma's sake, or to improve upon it when the opportunity arises?
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Old 12-03-2015, 04:21 PM   #2
Patrick A Horsman
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Re: Redefining the relationship between Power and Intensity

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Originally Posted by Dane Thomas View Post
The terms "force", "work", "distance", "time", "power", "area", and "intensity" all have well-defined meanings within the field of physics, and the relationships between these terms are precisely understood. Power = Work / Time, and Intensity = Power / Area (where the area is an imagined surface that is perpendicular to the direction of propagation of the energy)

When writing for a more general audience there is a natural temptation to descend from these precise usages to more colloquial definitions. I do not, however, feel that this makes it accurate to claim that in the field of human performance "...power is the definition of intensity...", or that "...intensity is defined as power.". I can memorize those phrases to get a better grade on a certification test, but that does not make them factually correct. Likewise, the fact that the phrases came directly from Coach Glassman in an article published in 2002 and have been repeated by countless other since then also does not make them any more scientifically accurate.

It seems to me that a program that is empirically driven, clinically tested, and community-developed, with an open-source charter that makes co-developers out of participating coaches, athletes, and trainers through a spontaneous and collaborative online community should welcome a discussion on this topic. Doing so could improve the general level of understanding and consensus, and potentially enhance something that is already very good. Think of it as a way of chasing intellectual virtuosity.

Please be assured that I understand and agree with the spirit of the point being made by the phrases. I just think that making the point while respecting the terms in question would make the argument more sound.

I think that it would be more accurate (yet still understandable and meaningful) to say that power is directly correlated with intensity, which in turn has been linked to nearly every positive aspect of fitness.

Anybody else out there agree? Is it more laudable to preserve dogma for dogma's sake, or to improve upon it when the opportunity arises?
I suspected that: "The word "intensity" [as used here] is not synonymous with "strength", "amplitude", "magnitude", or "level", as it sometimes is in colloquial speech" (directly from wikipedia on intensity).

However, if it was intended to be used in the true physics since (which I doubt) I still believe it is relatively accurate.

Given that Power = work / time and Intensity = Power/Area then it logically follows from the same article that if we are discussing a moving object rather than a wave:

"Intensity [of a moving object] can be found by taking the energy density (energy per unit volume) at a point in space and multiplying it by the velocity at which the energy is moving. The resulting vector has the units of power divided by area."

Energy per unit volume may differ from person to person, but within the individual with a given implement in a given workout the unit volume would be a constant no matter how fast the individual was moving. Thinking about it differently, the dimensions of the imagined perpendicular surface for each movement would not change.

if Area is therefore a constant when comparing within the individual (=1) then Intensity (within an given individual) = Power /1.

Given that we define intensity in CrossFit as only being relative to the individual I think the statement that Intensity = Power is actually accurate.





Also I think you can tell I had some time to kill at work today.

Last edited by Patrick A Horsman : 12-03-2015 at 04:35 PM.
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Old 12-03-2015, 06:13 PM   #3
Sean J Hunter
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Re: Redefining the relationship between Power and Intensity

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Also I think you can tell I had some time to kill at work today.
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Old 12-03-2015, 11:45 PM   #4
Dane Thomas
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Re: Redefining the relationship between Power and Intensity

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Originally Posted by Patrick A Horsman View Post
I suspected that: "The word "intensity" [as used here] is not synonymous with "strength", "amplitude", "magnitude", or "level", as it sometimes is in colloquial speech" (directly from wikipedia on intensity).

However, if it was intended to be used in the true physics since (which I doubt) I still believe it is relatively accurate.

Given that Power = work / time and Intensity = Power/Area then it logically follows from the same article that if we are discussing a moving object rather than a wave:

"Intensity [of a moving object] can be found by taking the energy density (energy per unit volume) at a point in space and multiplying it by the velocity at which the energy is moving. The resulting vector has the units of power divided by area."

Energy per unit volume may differ from person to person, but within the individual with a given implement in a given workout the unit volume would be a constant no matter how fast the individual was moving. Thinking about it differently, the dimensions of the imagined perpendicular surface for each movement would not change.

if Area is therefore a constant when comparing within the individual (=1) then Intensity (within an given individual) = Power /1.

Given that we define intensity in CrossFit as only being relative to the individual I think the statement that Intensity = Power is actually accurate.



Also I think you can tell I had some time to kill at work today.
Thanks for this! You are of course correct that they are equivalent within this single, narrow context. Even so, I think that my suggestion (that Power and Intensity are correlates, rather than one being the definition of the other) could be considered to be correct within a much wider range of contexts. Would that not be an improvement?
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Old 12-04-2015, 09:17 PM   #5
David Meverden
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Re: Redefining the relationship between Power and Intensity

I think I can help fill in a gap in the OP.

The term POWER has a scientific and a "dumbed down" colloquial definition that both get used, and often conflated, in these discussions.

The term INTENSITY has a scientific definition, but it also has OTHER definitions that, while less clearly defined, are useful in these discussions and equally legitimate as a meaning of the word. Once you accept that these other definitions are not "dumbed down" versions of the Power/Area concept, but are expressing a different concept, then the correlation of power to intensity makes sense.

Intensity is "the quality of being intense" and intense is "of extreme force, degree, or strength". In the context of CrossFit workouts the "intensity" will be a measure of how extreme the metabolic fatigue is (in other types of training it means something else, but lets not get distracted).

If this definition is used then power WILL be a measure of the relative intensity of a workout. If I do 10 rounds of Cindy in 20 minutes then the work done per time is low and the intensity of the work out for me is low. I'll have plenty left in the tank at the end. If I do 20 rounds in 20 minutes then the work per time is doubled, as is the intensity of the workout for me.

Now that explanation isn't perfect (for instance, metabolic intensity won't go up linearly with power as you start to get near max capacity) but if you start dissecting it at that level you will miss the forest for the trees. These concepts merely help us frame and understand issues of human performance and health.

Does that help?
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Old 12-04-2015, 11:21 PM   #6
Sean J Hunter
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Re: Redefining the relationship between Power and Intensity

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Old 12-05-2015, 12:01 AM   #7
Sean J Hunter
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Re: Redefining the relationship between Power and Intensity

Not a physics guy, not much of a kinesiology guy either, for that matter, but here's my take on it...might be wrong...I look forward to being corrected.

1) Its easy to get bogged down in the word Intensity. When looking for a word to decribe what this 'thing' is, it's probably the best worst thing we could find in Phsyics vocab to decribe it. My understanding is it's technically a deriviative of the actual Physics term. So kinda correct.

2) I think we might be mixing up effort with intensity here, two different things in my book.

Intensity is a metric used to decribe the relationsbhip between amount of resource used per cycle (rep) and the number of cycles (reps) when there's a fixed variable of wanting to use 100% of the resource (go to max reps) i.e. 5RM = 87.5% of 1RM.

Effort is how much of that resource you use, or more precisely how much you deplete.

For example, my 1RM DL is 200kg. my 5RM is 87.5% of this (less intense) = 175kg. And on deload days I do 70% 5RMs = 122.5. (less effort) (but I still do 3 sets = volume)

Intensity = 100% 87.5% 87.5%
Effort = 100% 100% 70%

Another example is how you don't want novice lifters lifting to 100% effort every lift otherwise it encourages an early stall effect.

So a novice may do 5RM for 3 sets (volume) but you want him lifting to 95% effort (i.e. last rep should be fast, not a grind). That's one reason why its poor programming to simply say do 3 x 5 DL to a new PR for a noivce, they're gonna overlift and stall early, or underlift and not gain. Targeted Effort = Optimal novice gains.

Intensity vs Effort

Still can't speak into the Power = Intensity thing. But it's interesting. Do we have a link to Coaches discussion on this?

Sean

Last edited by Sean J Hunter : 12-05-2015 at 12:25 AM.
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Old 12-05-2015, 12:59 AM   #8
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Re: Redefining the relationship between Power and Intensity

Article on Intensity vs Effort

This is why I have an issue with the term "High Intensity Training", what we're really trying to achieve is High Neuroendocrine Response, which tends to be best achieved thru maximal effort over short time, shocking the body into a greater neuroendocrine response.

Its Maximal Force in a short period of time = Power while using maximal effort. So what we do is High Power Max Effort Training?

The reality is once we get to Power, any other term after this, Intensity, Effort, Volume, Training Resource, are at best using physics terms ina derivative fashion.

Another issue is the term Max Effort Training, which discusses lifting at 90% or more of your 1RM. so 1-3 RM. This is an incorrect use of the term Effort. Similar to how Power lifting isnt about speed, which differentiates Power from Force.

Sean
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Old 12-09-2015, 11:30 AM   #9
Sean J Hunter
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Re: Redefining the relationship between Power and Intensity

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Originally Posted by Patrick A Horsman View Post
But if it was Force lifting I wouldn't be able to do it - I'm not Jedi
lol, ok what did I miss here....I a terrible at using terms correctly. :P

Sean
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Old 12-09-2015, 11:39 AM   #10
Patrick A Horsman
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Re: Redefining the relationship between Power and Intensity

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Originally Posted by Sean J Hunter View Post
Article on Intensity vs Effort

This is why I have an issue with the term "High Intensity Training", what we're really trying to achieve is High Neuroendocrine Response, which tends to be best achieved thru maximal effort over short time, shocking the body into a greater neuroendocrine response.

Its Maximal Force in a short period of time = Power while using maximal effort. So what we do is High Power Max Effort Training?

The reality is once we get to Power, any other term after this, Intensity, Effort, Volume, Training Resource, are at best using physics terms ina derivative fashion.

Another issue is the term Max Effort Training, which discusses lifting at 90% or more of your 1RM. so 1-3 RM. This is an incorrect use of the term Effort. Similar to how Power lifting isnt about speed, which differentiates Power from Force.

Sean
But if it was Force lifting I wouldn't be able to do it - I'm not Jedi
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