Rough guess on FTP based on 5 minute test

I have not done an FTP test for almost a year now. I was out riding and feeling pretty good last night. Was on a nice piece of road. I did an all out 5 minutes. I know that 5 minutes is not going to be too accurate. But any multiples to use on a 5 minute test?

When I did test FTP last year I used the 20 minute test. I remember that for the 20 minute test you use a multiple of .95.

When I did test in the past I did it on the CT. I honestly don’t know how people do this test on real streets. Twenty minutes is tough but one hour, flat, no traffic, is really, really difficult to find.

I have a nice 3 mile piece of road but still have to cross railroad tracks. Plus three intersections I have to be careful.

This winter I plan to get back on the trainer but man it is really tough on my body and especially my knees.

Thanks in advance!!!

it just can’t work. anaerobic systems confound the value too much over just 5 minutes. there could be 50 watt swings.

FWIW - In his book The Time Crunched Cyclist, Chris Carmichael prescribes a field test of 2x8 minutes. Using the interval that produced the highest power number, he multiplies that by 90% and uses that figure to establish training zones.

Thanks. The actual time length actually ended up being 6 minutes. If I use 73% I get my FTP last year when I tested. I had thought my FTP had dropped but I don’t think so. On another web site they had an FTP test of 5 minutes and suggested using 82%.

Also thanks Jack. Personally, I really question that accuracy of a FTP test of even 20 minutes. I never went ahead and did the hour test but I seriously questioned if I could hold the 90%-95% of my 20 minutes FTP for an hour. Plus most of my training is endurance in nature. So, for example, when swimming my 500 yard per 100 time is only 6% faster than my 2.4 mile per 100 time. Always thought that was crazy.

If knees continue to feel good maybe I will remount my bike and put the trainer wheel back on and do a real test on the CT

generally you do 5 minutes all out before the 20 minute test, then multiply by .95

none of these methods are perfect nor are they meant to be, you don’t need a perfect answer.

but 5 minutes…that test would probably put my ftp at 300, and it isn’t 300!

Also thanks Jack. Personally, I really question that accuracy of a FTP test of even 20 minutes. I never went ahead and did the hour test but I seriously questioned if I could hold the 90%-95% of my 20 minutes FTP for an hour. Plus most of my training is endurance in nature. So, for example, when swimming my 500 yard per 100 time is only 6% faster than my 2.4 mile per 100 time. Always thought that was crazy.

If knees continue to feel good maybe I will remount my bike and put the trainer wheel back on and do a real test on the CT

You’ve got 2 options:

1 - get on the trainer and do the hour test.

2 - don’t worry about FTP and just train.

Guessing based on 5 minute bursts is just that - guessing. Worthless.

You’ve got 2 options:

1 - get on the trainer and do the hour test.

2 - don’t worry about FTP and just train.

Guessing based on 5 minute bursts is just that - guessing. Worthless.

  1. There is no need to do an hour long FTP test on the trainer. A few of the shorter CP test will do fine. Save the hour long all out efforts for a race.

  2. If you have spent all that money on a PM you may as well use it!

You simply cannot generate a decent inferential model from 5min power to FTP, there are way too many variables that can confound/unknown. But, then again unless you are training at the extremes (lots of speed or only LSD) then it might get you in the ballpark, go to cycleops and use their FTP generator (i think from 5min power it gives FTP, but in my opinion slightly conservative).

Also, in my case my 5 min power sucks but i have a decent FTP, while other people (especialy crit racers) could have amazing 1-5-10-15min power but have relatively low FTP’s.

Yes I did the 5 minutes all out first. I actually followed the protocol to a tee

Yeah, the 82% method gives me an FTP of almost 300… my actual FTP is noodling around somewhere in the vicinity of 260. Pretty big difference.

Sorry if misunderstood. I did not plan to do 1 hour on the trainer. I was going to do 20 minutes. But lots of hassle doing this. Have to change tire on wheel, connect bike, and the worst part, actually do the test, indoors. This is without being on the trainer in almost a year so even more painful than usual.

Always looking for new things with training so I am doing the improve FTP protocol shared with me in another thread by msuguy512. Also been reading the Fletch thread. So wanted FTP to work with. But I think I will use my old FTP and then depending how tired I am modify. Right now, I think the improve FTP protocol does not look like enough so might increase FTP estimate a little.

I actually did not have the details when I was riding and I did five 6 minute intervals with 8 minutes of 60% FTP rest. This was done because of the road setup more than anything else.

It has been a long time since I have really got to push it and have that exhausted feeling afterwards.

You could do a 3 minute all out, and from the 3 minute and 6 minute you could estimate a FTP using the critical power equation
.

Sorry if misunderstood. I did not plan to do 1 hour on the trainer. I was going to do 20 minutes. But lots of hassle doing this. Have to change tire on wheel, connect bike, and the worst part, actually do the test, indoors. This is without being on the trainer in almost a year so even more painful than usual.

It has been a long time since I have really got to push it and have that exhausted feeling afterwards.

It’s time for a hot cup of HTFU.

It’s just 20 minutes (25 really) stare at the wall and imagine how awesome it will be to be finished.

I have not done an FTP test for almost a year now. I was out riding and feeling pretty good last night. Was on a nice piece of road. I did an all out 5 minutes. I know that 5 minutes is not going to be too accurate. But any multiples to use on a 5 minute test?

When I did test FTP last year I used the 20 minute test. I remember that for the 20 minute test you use a multiple of .95.

When I did test in the past I did it on the CT. I honestly don’t know how people do this test on real streets. Twenty minutes is tough but one hour, flat, no traffic, is really, really difficult to find.

I have a nice 3 mile piece of road but still have to cross railroad tracks. Plus three intersections I have to be careful.

This winter I plan to get back on the trainer but man it is really tough on my body and especially my knees.

Thanks in advance!!!

13 posts and no one mentions Alex Simmons?

OP, if you have only a trainer, i’d suggest you do the MAP test suggested by Simmons. At least you can set up your zones & start periodize your training

More on MAP tests here and here

I really question that accuracy of a FTP test of even 20 minutes.

I prefer 2 X 20’ separated by a 2-3’ easy spin and then average the entire 42-43’ segment. I have found this to be the most accurate way of defining FTP for myself.

The MAP test should give him about the same number as his 5-6 minute effort, so what would he be gaining? He still would not know his FTP.

Sorry if misunderstood. I did not plan to do 1 hour on the trainer. I was going to do 20 minutes. But lots of hassle doing this. Have to change tire on wheel, connect bike, and the worst part, actually do the test, indoors. This is without being on the trainer in almost a year so even more painful than usual.

So, assuming you do the “test” indoors on the trainer… Are you also planning on doing all of your power-based training indoors on the trainer?

I don’t know about you, but there is a difference between my indoor & outdoor FTP that, while not great, is not negligible, either.

Food for thought.

I don’t only have a trainer. But there is not a convenient place, that I know about, where I can bike 20 minutes, flat, without distractions. So the trainer is the ideal place to do a FTP test.

The MAP test should give him about the same number as his 5-6 minute effort, so what would he be gaining? He still would not know his FTP.

It’s a stepped test that establishes FTP to be 72%-77% of MAP. You won’t know the true FTP, but you at least have a place to start for assessing training stress.

I really don’t know my FTP outside. I have only done the test indoors on the trainer. I think I will just use what I think it is and work from that. Then adjust according to how hard it is on me.

Then this winter will go back to the trainer and set everything back up