So, I think I understand pretty well the difference between average power and normalized power, and I use NP to calculate TSS, CTL etc for individual workouts. However, training zones are typically scaled according to FTP which is usually expressed as average power. When I get home for a ride and check to see how well I stayed in the targeted zone for that day I tend to use NP, but it occurred to me today that I am thereby comparing NP and AVG power.
Now for a TT (at least on flat(ish) ground) avg. power and NP will typically be about the same, so with respect to determining training zones that does not seem to matter much. But AVG power and NP are widely different on individual rides in the very hilly terrain I'm living in at the moment. I use the "current" power (?) readout during the ride to determine whether I'm riding at an appropriate level. But what about when thinking about the workout as a whole --whether it was a "good" Zone 3 ride, for example.
So: thoughts on using NP or Avg power when evaluating a workout relative to targeted training zones?
You need to look at AP when thinking about zones, but frankly, if your riding a hilly or stop/start course then there really isnt any point in using those metrics at all as they dont tell you very much useful at all. Far better is to look at your 'time in zone' for the ride and see how much time you actually spent in L1/2/3/4/5/6 etc. An AP of 200w tells you nothing about what you actually did - was it a steady 200w for 2 hours or was it continually pushing 300w+ on hills and coasting down the other side. Both could give similar AP stats but be completely different workouts obviously.
IIRC there is an entire section devoted to this in Coggans book Training and Racing with Power, so if you havent read this book you should get it ASAP. You also want to be ideally using some form of software to analyse your ride data, eg Golden Cheetah or Training Peaks etc, as this will give you far more useful data than simply looking at stats for an entire ride or session.
Honestly, pick one and stick with it. As long as you are always using the same methods, then it won't matter much which you use. Whatever makes your ego feel better 😉
