But - say I've done a 20 minute time trial, to estimate FTP and ended with 220W. Then I do a 2hr road race (hard, on the rivet the whole time), and my normlaised power is 220W, but my peak 1 hour is an average of 203W with NP of 249W.
Alex Simmons says
Normalised Power (from a Hard ~1hr Race)
#4 is pretty handy, particularly as an indicator of when a rider's FTP may have changed. Frequently riders who do not do time trials, but do other races such as shorter road races or criteriums of approximately 1 hour duration, can use this as a crosscheck of their current FTP. Assuming the race was hard (that is, you were pretty much on the limit for most of the race), and you were not overly fatigued beforehand, then the 60 minute maximal Normalised Power should be at least at your FTP if not a little higher (up to about 5% higher). If your 60 minute Normalised Power is reported as more than 5% above your FTP, then that is a strong sign that your FTP needs re-setting (upwards).
So I guess my FTP is too low? The intensity factor was 1.05 for 2 hours, which seems high.
I wouldn't be surprised if my FTP was too low - I am a horrible time trialist!