# Field test with the Powertap



## Gall (Feb 6, 2004)

Hello,

I just got a Powertap and I need to do my field test. What method do you all use and why?

I thought the one Dr. Lim shows on the Powertap web site would be practical because its done on an indoor trainer and would lead to similar conditions. 

What do you think?

Thanks!


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## Alex_Simmons/RST (Jan 12, 2008)

Gall said:


> Hello,
> 
> I just got a Powertap and I need to do my field test. What method do you all use and why?
> 
> ...


what are you testing for?

Functional threshold power
maximal aerobic power
aerodynamic drag


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## Gall (Feb 6, 2004)

*Functional threshold power /Thanks*

Functional threshold power


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## Alex_Simmons/RST (Jan 12, 2008)

Gall said:


> Functional threshold power


okay, there are several methods so I'll post all the ones I am aware of:

Quote Dr Andrew Coggan:
_
"the seven deadly sins....

...er, ways of determining your functional threshold power (roughly in order of increasing certainty):

1) from inspection of a ride file.
2) from power distribution profile from multiple rides.
3) from blood lactate measurements (better or worse, depending on how it is done).
4) based on normalized power from a *hard *~1 h race.
5) using critical power testing and analysis.
6) from the power that you can *routinely *generate during long intervals done in training.
7) from the *average *power during a ~1 h TT (the best predictor of performance is performance itself).

Note the key words "hard", "routinely", and "average" in methods 4, 6 and 7..."_

#7 is obviously the "Gold Standard".

I'd suggest the SDS also include:

- a percentage range of the average power of time trial effort of sufficient duration (say at least 20-min), with FTP typically falling into a range of percentages for TTs of this duration (e.g FTP =95%+/- 3% of 20-min max avg power or 96% +/- 3% of 16km (10-mile) TT avg power).

- a percentage (typically 72%-77%) of Maximal Aerobic Power, with MAP measured by conducting a MAP test using the test protocol on Ric Stern's website:
http://www.cyclecoach.com/pageID-news-Test_yourself.htm.
An example here: http://alex-cycle.blogspot.com/2006/12/map-testing-where-failure-is-success.html

Remember that they are all just ways of estimating FTP and some are better than others at nailing down the number (and for many, some are more practical to perform than others). The above would typically get you to within a few percent either side and can then be cross referenced with another method. 

It depends on the rider's circumstances. Not everyone is in the position to do a ~1hr TT with sufficient regularity.

I can feel a blog post coming on ...


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## Alex_Simmons/RST (Jan 12, 2008)

*How to test for or estimate FTP / Seven Deadly Sins +2*

Apologies in advance for the cross post on a few forums.

I have been hanging around various forums lately and noticed what
seems like an increase in the basic questions of how to test for and
estimate one's Funtional Threshold Power (FTP). Perhaps the ever
growing number of new power meter users is rehashing the same issues.

Now of course the topic in general is not new and has been discussed
at length in many threads, is discussed in "The Book" and is well
covered in the Cycling Peaks web site power training section.

Nevertheless, I thought it worthwhile to go over old ground and write
another summary talking through the methods, providing a few links and
other comments.

I post the link simply to be picked up in any searches of the topic.

http://alex-cycle.blogspot.com/2008/05/seven-deadly-sins.html

Function Threshold Power
FTP
Seven Deadly Sins
Critical Power
Power Profile
Blood Lactate Measurement
Maximal Aerobic Power
MAP Testing
Time Trial Power


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