Cricial Power info



rkohler

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Sep 11, 2003
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Regarding Critical Power that you would see in Joe Friel's books, etc., does anyone know of any equations that are out there to estimate CP for any given time based on a power at max that could be found during a VO2 max test, field test-type of power (max sustainable), or wingate test?

I know that we can get CP60, for example, by riding at the max sustainable power for 60 minutes, and CP120 the same way, and so on. But is there any info out there that allows us to estimate CP values based on shorter duration times?

Thanks!
 

acoggan

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Jul 4, 2003
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...and learn to think in terms of the original critical power, as defined in the scientific literature. To be brief: plot work performed (in J - obtained by multiplying power in W by time in s if need be) vs. time (in s) for a variety of maximal efforts ranging from 3 to perhaps 30 min in duration. The slope of the best-fit line of this relationship is your critical power, which is "an intrinsic characteristic of the aerobic energy system" and "an intensity that can be maintained for a very long time w/o fatiguing". The intercept, OTOH, reflects your anaerobic work capacity (AWC), i.e., the amount of work (not power) you can produce anaerobically, above and beyond which all work must be accomplished aerobically. There are limitations to this overly-simplistic model of exercise performance, but it is still quite useful e.g., as a means of tracking fitness.

More info can be found in the chapter on power-based training that I wrote for the USAC Expert Coaching manual, copies of which are floating around on various places on the web...
 

claytid

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Dec 12, 2003
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Originally posted by rkohler


I know that we can get CP60, for example, by riding at the max sustainable power for 60 minutes, and CP120 the same way, and so on. But is there any info out there that allows us to estimate CP values based on shorter duration times?

Thanks!

Not sure if this is exactly what you're looking for but Eddie Monnier's article on CP is pretty helpful and includes a spreasheet that allows you to predict avg power for a particular time.

http://www.velo-fit.com/articles/critical-power.pdf

Clay T.