1st FTP Test

[madmacca]

So I did my 1st 20 minute FTP test last night (on an outside velodrome).

It kind of settled in at 256W for the first 15 minutes, and I just didn't really seem to be able to hold a higher effort than this (in hindsight maybe I had the gearing a bit wrong?). But I pushed harder for the last 5 minutes at 273W, for an 20 minute average of 261W, or an implied FTP of 247W. But it was only during that last 5 minute effort that my heart rate even got to 90% of max.

Now I get that a first FTP test is always a learning experience, and that I went out a bit conservatively, but my question is:
Given the data above, what should I be shooting for in terms of my next test?

[Alex Simmons/RST]

So I did my 1st 20 minute FTP test last night (on an outside velodrome).

It kind of settled in at 256W for the first 15 minutes, and I just didn't really seem to be able to hold a higher effort than this (in hindsight maybe I had the gearing a bit wrong?). But I pushed harder for the last 5 minutes at 273W, for an 20 minute average of 261W, or an implied FTP of 247W. But it was only during that last 5 minute effort that my heart rate even got to 90% of max.

Now I get that a first FTP test is always a learning experience, and that I went out a bit conservatively, but my question is:
Given the data above, what should I be shooting for in terms of my next test?

Well done on your first attempt although I'd call it 20-minute power test, not an FTP test.

To get a more reliable FTP estimate it would help to supplement such a test with another from a shorter duration of around 4-5 minutes.

Then you can use this formula as one way to estimate FTP, where y-min is the longer duration effort:

y-min test (between 20-30-minutes): Y watts (average power)
x-min test (between 3-5 minutes): X watts (average power)

FTP = (y*Y - x*X)/(y-x)

You can use minutes or seconds and get same answer, as long as you use same units for both x and y.

It'll also give you an estimate of work capacity above threshold, aka: W', AWC, or FRC, where:

FRC = (X - FTP)*x
also = (Y - FTP)*y

but to have the answer in joules, x (or y) needs to be in units of seconds.

e.g. say you had a 5-min test and averaged 320W to add to your 20-min test of 261W

FTP = (20*261 - 5*320) / (20-5) = 241.3 W
(call it 240 W)

5-min = 5*60 = 300 seconds

FRC = (320 - 241.3) * 300 = 23610 J
(call it 23.6kJ)


Learning to pace is something which comes with experience. Next time you might choose to start at ~260W and see how you go.

During such tests, if you realise you under cooked the opening by a reasonable margin, then rather than attempt to over power the final minutes instead try lifting power a bit more subtly and extend the test, then pick the latter 20-minute section to assess average power.