# FTP Test - How accurate is the 20 min vs one-hour TT?



## lemonlime (Sep 24, 2003)

Six weeks ago I did the 20 min FTP test from Coggan's book. So I took 95% of the average and came out with a number I'm too embarrassed to mention. Regardless... 

For shits and grins, last week I did a one-hour TT and that average was exactly the same as what I had in the 20 min test.

Yesterday I did the 20 min FTP test again and game up with a number 20 watts higher than before. But I'm *pretty* sure I can't hold that wattage for a full hour.

Should I try the one-hour TT again to confirm the 20 min test result? Do I chalk up the improvement to my training working (i.e. higher FTP) or some sort of anomoly? Should I base my zones now on the new number? Somewhere inbetween?

Thoughts?


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## sdeeer (Aug 12, 2008)

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

Is a good read on the topic.

The 20 min test can overestimate power. I use only my 20 min test to estimate FTP right now. 

I would move the numbers up, but make sure that it is appropriate for my intervals. I.E. when I do an interval at the new 90% of FTP, do I feel the same (now that I am potentially more fit) as when it was lower.

But I am far from an expert on training with power........


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## rbart4506 (Aug 4, 2004)

Have you checked your Powermeter to make sure it is properly zero'd and torque calibrated??

Back in the summer I had a fantastic ride, all my power numbers were up by 15 watts...WOW! I thought....Until I was riding home and descending into valley, whilst coasting I was constantly showing wattage.

Turns out my Powertap's torque tube was shot and needed replacing.

Once I got the wheel back I once again sucked


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## pretender (Sep 18, 2007)

Testing is training. Training is testing.


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## zakyma (Jan 25, 2010)

20 Min test used to determine threshold power.

Ftp is lower than the 20 min test. You should based your training on the 20 min test.


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## kbiker3111 (Nov 7, 2006)

Was it actually a TT or did you just go to an open road and ride hard for an hour? You may be surprised what you can do when competitively challenged for an hour. 

More importantly I wouldn't worry about defining that number _exactly_. It doesn't really matter what you threshold is, just that you consistently define it the same way and use it to base your intervals off. Nobody is exactly the same, so those zones are guidelines more than anything.


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## PissedOffCil (Jan 3, 2008)

The 20 minute test tends to give high numbers. The general guideline in taking 5% off this number.
The 60 minute test is hard to pace and easy to blow out.

What I have done with good success is 2x20 as hard as you can. Take the 2nd 20 minute segment as-is for your FTP. The 1st should give you a higher number and get you tired, so the 2nd is a good evaluation of your FTP.

Every so often I do a 1x60 at FTP to correlate the values obtained. Since I'm pacing myself with FTP, not trying to achieve the best result, you can easily know if you under evaluate or over evaluate or are dead on afterwards.

One way or another, the same test done on 2 different days yields different results, a mean-max normalized power over 60 minutes should give a good estimate too.


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## IAmSpecialized (Jul 16, 2008)

Agreed, testing is training and training is testing. Taking 95% of a 20 minute effort is as HIGH as you want to take and frequently you will find it is overreaching, but like someone has mentioned it provides an estimate.

Do not get hung up on ONE NUMBER. FTP is what you can average over a 60 minute time trial in optimal condition. You will also have days where you can average a bit over that and there will be days you won't be able to reach your FTP. So don't get to wrapped up in finding that ONE NUMBER. Try to find a very accurate estimate that you can base your training on. Your FTP is also self correcting. It wont' take long to figure out if you're using the wrong number. If it is too high you will not be able to complete your workouts. If it is too low you will find yourself feeling like you're not really working as hard as you imagine you should feel.

Now, here's my other two cents. I have been really hung up on that one number myself (I have finally got over that issue). What I did to make me feel really really confident that I was using the right FTP to base training on was this: I did several tests. I organized a group ride with some guys that I know are stronger than me and so I knew the ride would force me to work as hard as humanly possible. It was a 2.5 hour ride which actually give me about 1.25 hours of full blast, no holds barred, need to vomit on the side of the road, intensity. That was on a Sunday. I looked at the file and wrote down the peak 60 minute normalized average. Did active recovery for the next two days and then on the third day I went out by myself for solo testing. I used Hunter Allen's FTP protocol. One of the big things with his protocol is the 5 minute blow out effort must be done FULL BLAST BLOW OUT. It hurts like a motherf*cker and you will think that it will cripple you to the point you won't be able to do the 20m FTP test, but it actually enables you to do the 20 minute effort much harder. Trust me on this one. Once I got ready to do the 20 minute effort (after 10 minutes recovery from the 5 minute blow out effort) I used my normalized power number from Sunday (which in theory should have been pretty close to FTP b/c I know I worked as hard as possible during the Sunday ride with 2 other guys who pushed me to my limits) to pace myself with for the first 5 minutes of the 20 minute FTP protocol. After pacing myself with that number for 5 minutes I stopped looking at my computer and just pushed as hard as I possibly could for the next 15 minutes based on perceived exertion.

Here is what I found. My 20 minute effort AVERAGE power mutiplied by 0.95 was exactly 1 watt difference from my peak 60 minute normalized average from the Sunday ride. Because I also knew for a fact that my 5 minute blow effort during testing was a true BLOW OUT EFFORT (almost couldn't turn my pedals afterwards) I used that average and the 20 minute average together and plugged them in the Critical Power model to see what FTP number it would give me. The way the model works is you do two maximal tests, one of 3-6 minutes and one of 20-30 minutes, on non-consecutive days within a 7-10 day period. The equation is then: (long interval duration * long interval average power) - (short interval duration * short interval average power) divided by (long interval duration - short interval duration) = CP ~ FTP.

Guess what? The CP model put my FTP within 2 watts of the Sunday normalized average and within 1 watt of 95% of the 20 minute effort.

Was all this really necessary? No. But, after it was all done I felt very confident in the number I was using as my FTP. So for people who must feel really good about the number, this is one way to go about doing it.

Sorry for being so long with the reply. Remember, training is testing and testing is training. FTP is self correcting.


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## IAmSpecialized (Jul 16, 2008)

BTW, I suspect you are not a member of the Wattage group on Google? You will find a huge amount of info there on training with power. It's an invaluable resource.

http://groups.google.com/group/wattage

Join the group, you'll be glad you did. Both Hunter Allen and Andy Coggan post there frequently.


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## clonechemist (Sep 8, 2006)

IAmSpecialized said:


> ....


Thanks for sharing; as someone fairly new to power it's reassuring to hear such a seemingly blinded/scientific case gave such reproducible numbers.


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## IAmSpecialized (Jul 16, 2008)

clonechemist said:


> Thanks for sharing; as someone fairly new to power it's reassuring to hear such a seemingly blinded/scientific case gave such reproducible numbers.


I'm not new to cycling per se, but I too am new to power. I'll say from the outset I am no expert and I do not wish for my contribution to sound as such. It's just my two cents at this point in my training with power. I am three weeks new to training with power. From day one I felt like I absolutely had to know my FTP and it had to be perfect. I obsessed with it for days on end. There were actually nights I didn't sleep because I kept wondering how would I ever be able to train with power if I didn't know my FTP right down to within 1 watt. So I know what it's like to feel like you must have that number, especially since your training plan is largely based around an accurate FTP. Fortunately I do not obsess like this now, but that's largely b/c I got my initial FTP to seed with.

I think I've started to "get it" now, since I actually have figured out my FTP. I "get it" that FTP really does self correct. But no matter what other people tell you, you have to feel good about the number you are using. It can wreak havoc mentally if you don't initially feel comfortable with that number. So for those of us in this boat, I really think using a combination of testing methods during a week can make you feel confident about your FTP.

Once you have that number and you start training based on that number, you will figure out real quickly what "self correcting" means. And I think from that point forward you will really feel confident in future testing. 

Don't be dishonest with yourself either. If you didn't go full gas, don't lie to yourself and say you did. Make sure you go full gas. On shorter testing like 5 minute blow outs, etc. go so hard you think your legs are actually going to explode, and then push harder. Yes, it sucks like you would not believe. 

One thing you might find, at least I did, is once you know your FTP number and you start basing your training on it, you will find that you have NOT been riding hard enough during "hard rides," and you have NOT been riding easy enough during "easy rides" and especially recovery rides. The hard rides become much harder my friend...but if you have numbers you at least know it is within your reach...but it hurts much more now than before the PM.

Of course don't forget, "All you can do is all you can do."

Yes, I'm very long winded. I apologize.


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## iliveonnitro (Feb 19, 2006)

For me on a good day: 92% of my 20MP is my FTP (very high anaerobic capacity).

For one of the people I coach, it is almost 97% (not very good anaerobic capacity).


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## estone2 (Sep 25, 2005)

iliveonnitro said:


> For me on a good day: 92% of my 20MP is my FTP (very high anaerobic capacity).
> 
> For one of the people I coach, it is almost 97% (not very good anaerobic capacity).


+1. The higher your anaerobic capacity, the worse of an indicator it is. The more of an aerobic rider you are, the better. I am ~98% - and if you ever see me ride above FTP, you'll understand why!


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## pretender (Sep 18, 2007)

Hasn't the whole concept of "lactate threshold" been more or less discarded? Isn't it more accurate to speak simply of 5-min power, 20-min power, 60-min power, etc, i.e. power profiles?

I thought the big advantage of a power meter (and accompanying software) was that it constantly updated your power levels based on workouts and racing.


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## estone2 (Sep 25, 2005)

pretender said:


> Hasn't the whole concept of "lactate threshold" been more or less discarded? Isn't it more accurate to speak simply of 5-min power, 20-min power, 60-min power, etc, i.e. power profiles?
> 
> I thought the big advantage of a power meter (and accompanying software) was that it constantly updated your power levels based on workouts and racing.


I'm guessing you're responding to me.

And yes, it is. And I used LT out of habit, I was actually talking about FTP, and specifically 60 minute power. Don't mind me, I'm antiquated.


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## iliveonnitro (Feb 19, 2006)

LT is not discarded by any means. The understanding of it, however, has changed quite a bit.


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## Kerry Irons (Feb 25, 2002)

*Fuzzy issue*



iliveonnitro said:


> LT is not discarded by any means. The understanding of it, however, has changed quite a bit.


I think the problem is that academics have tended to define LT as a specific concentration of lactic acid in the blood, using the same number for every person. This is probably bogus on the face of it because we all are different to varying degrees. It makes it "easier" to compare research results if LT is defined as so many mmoles/liter but it can lose its meaning due to individual variations.

That said, your max sustainable (20 minutes +) HR, anaerobic threshold and lactate threshold are all "about" the same number, and given the other variables that can affect HR from day to day, those numbers are more than good enough to form a basis for a training plan.


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## iliveonnitro (Feb 19, 2006)

Kerry Irons said:


> I think the problem is that academics have tended to define LT as a specific concentration of lactic acid in the blood, using the same number for every person. This is probably bogus on the face of it because we all are different to varying degrees. It makes it "easier" to compare research results if LT is defined as so many mmoles/liter but it can lose its meaning due to individual variations.
> 
> That said, your max sustainable (20 minutes +) HR, anaerobic threshold and lactate threshold are all "about" the same number, and given the other variables that can affect HR from day to day, those numbers are more than good enough to form a basis for a training plan.


And each person is different in the ability for them to cope with said various concentrations of lactic acid in the blood.

However, OBLA etc are still useful, and used.


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## BikeShopMonkey (Nov 20, 2010)

iliveonnitro said:


> And each person is different in the ability for them to cope with said various concentrations of lactic acid in the blood.
> 
> However, OBLA etc are still useful, and used.



i found this to be very true. 20 minutes you will just begin to feel it at the end. as nutrition is eaten up, the closer you get to the 60 minute mark, the more you will feel like you are getting close to the end of the fuel tank. more effort is needed on my part even though the pace stays the same.

this happens to me when i do LT testing. i am fine with the 20 minute and even feel i might be able to squeeze out a few more watts. but if i keep the pace for 60 minutes, the right pace will be very exact. i will either be done or not. very black/white for me.


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## colinmcnamara (Dec 5, 2009)

Interesting note on the Critical Power curve. I was in your same boat at first, not trusting my critical power testing.

I did the 5+20 min CP test protocol initially and it came out with 311 watts. Through the following weeks I wasn't quite sure if that number was correct.

On thanksgiving morning I went out and used my FTP number to pace myself up mt diablo (4000 foot 7-8 percent hill climb). I then loaded that ride into Golden Cheetah and ran a critical power analysis graph on just that ride. Interestingly, the plotted curve was within 2-5 watts of my demonstrated power through that test.

In other words, the science is sound. 

--Colin


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## estone2 (Sep 25, 2005)

BikeShopMonkey said:


> i found this to be very true. 20 minutes you will just begin to feel it at the end. as nutrition is eaten up, the closer you get to the 60 minute mark, the more you will feel like you are getting close to the end of the fuel tank. more effort is needed on my part even though the pace stays the same.
> 
> this happens to me when i do LT testing. i am fine with the 20 minute and even feel i might be able to squeeze out a few more watts. but if i keep the pace for 60 minutes, the right pace will be very exact. i will either be done or not. very black/white for me.


It's different for everyone in that regard. 5 minutes into my 2x20s, I feel like I'm going to die and don't think I'll be able to hold it for 20 minutes. But, once I reach my 5 minute misery mark (I actually think of it as that ), I level out and am equally miserable for the next hour.


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## iliveonnitro (Feb 19, 2006)

colinmcnamara said:


> On thanksgiving morning I went out and used my FTP number to pace myself up mt diablo (4000 foot 7-8 percent hill climb).


I LOVED that climb. It was a fairly long drive from Palo Alto, but totally worth it. It started pouring for the last 30min of the climb. By the top, the fog was so thick that I could only see 15ft in front of me.

I didn't love the descent, though. Freezing cold, soaking wet, couldn't see anything, and way under-dressed.


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