pastorbillv said:
Help! I've been training with Power for a year now and with a coach since June. I'm lost between Normalized Power (NP) and Average Power (AP). What I mean is I'd like to use one or the other but...
O.K. let me try....
The primary purpose of NP is to provide an estimate of the metabolic demands of non steady riding. It's a way to account for the fact that bursty riding that includes high power peaks and rest is harder on the body than the average power for such an effort might suggest. So it helps to normalize the cost in terms of stress and fatigue that your body will experience across a wide range of steady and non steady rides and forms the basis of both IF and from it TSS, CTL, ATL, and TSB to track training load.
Since it estimates overall metabolic stress it can be used as a global constraint to workout sessions or variable power racing. IOW, since it does a fairly good job of estimating the effective metabolic stress you place on your body during sustained efforts and you can only sustain so much metabolic stress before you have to back off, it means NP effectively sets a limit to how hard you can push yourself
for sustained efforts even if the AP for those efforts isn't all that high relative to your MMP for that duration.
So a secondary use of NP is to set an upper bound in terms of how hard you can push yourself during bursty efforts combined with short rests. So it can help you predict whether you'll be able to finish a particular set of microintervals or help explain why a crit seemed really hard even though the AP wasn't all that high or help you understand why burst and rest TT pacing may not be the best strategy.
The idea of NP as an estimate of effective metabolic stress leads to a third use as a way to estimate FTP during hard bursty efforts of approximately an hour. If NP estimates effective stress on your body and you do a workout or race that's really bursty, pushes you very near your limit and is approximately an hour long then you can use the NP from that effort as an FTP estimate. But the effort needs to be approximately an hour long and very near your limit for the duration. If it was an easy crit or only lasted half an hour then it won't be a very good FTP estimate.
So your coach used NP from a 20 minute effort to estimate FTP......
If the test was near your limit and isopower then there's no reason to use NP, just use some scaled factor (and 0.95 isn't the gold standard as many folks think) of that 20 minute AP to estimate your FTP. If the 20 minute test was variable and bursty then I'd suggest a different venue or protocol for your FTP testing. 20 minute NP from a dynamic course or crit isn't a good choice for FTP estimation. 20 minutes is at the low end of the duration where NP becomes useful.. NP afterall estimates effective metabolic stress and 20 minute efforts have a reasonable AWC contribution which can be misleading.
Anyway, the purpose of NP is to estimate effective metabolic stress. It can be used in some cases to estimate FTP from hard bursty rides roughly an hour long. But that resulting FTP estimate is still in watts as RChung suggests. There aren't units of "watts" and "normalized-watts" FTP is simply stated in watts regardless of the method you used to estimate FTP.
...1. I train both in the mountains and the valley. In the mountains NP and AP vary a lot. In the valley, as expected, they're virtually the same...
Again, the most important use of NP is to estimate overall metabolic stress. In terms of training, pay attention to your AP for the climbing portion of your mountainous rides. That's the training stress that counts. If your AP drops because of the descents, that's not really relevant to your training efforts. Sure the NP resulting from the entire ride is still useful in terms of estimating overall IF, TSS, etc. but pay attention to your AP during the climbing portion of mountain intervals.
If you're talking about rolling terrain and not mountains then it becomes tougher but you should still be focused on the power during the climbing by avoiding the temptation to send it through the roof (unless that's the prescribed interval work) and then coast the descents. For long steady work in rolling terrain you should use all your gears and do your best to apply pedal pressure, power, and effort as steadily as you can. These are tough, but you post talked about mountains which generally means longer climbs followed by longer descents, in that case focus on the climbs and ignore the descents.
2. My PowerTap only doesn't show me NP (obviously, it can't).
Yep, but you don't need it. Base training efforts on AP and find the best venues for sustaining that AP for the prescribed durations. I have some climbs that are only good for 10-12 minute efforts, others that can work for 20-30 minute efforts but even with Teton Pass right down the road I have to do hour long FTP style efforts on the flats as none of the local climbs are long enough. Pick your training venues to match your workouts and pace those efforts on RPE and real time power.....
3. My coach has me do a 20 minute threshold test and uses NP to calculate my FTP. He then breaks that up into the typical L1, L2, etc. ranges. He then gives me workouts based on these ranges. Obviously, the ranges represent NP...
No, as mentioned above he used NP to estimate your FTP, but that FTP is still defined in watts and not "normalized-watts" the training ranges derived from that FTP are still defined in terms of AP.
4. I go to do my workouts with NP ranges, on a PowerTap that doesn't show NP (again, that's obvious)! Of course, he tells me that monitoring AP during an interval is so 90's-ish, that I must watch my actual power output and to stay in the range (which makes me feel like a drunk trying to walk a tight-rope). I like to watch my AP and stay at the high end of the range he gives me and then I come back and load everything into WKO+ only to find I've greatly exceeded my interval ranges with NP! UGH!...
It sounds like you need to work on steadier pacing. For steady intervals AP and NP should be quite similar. They only vary dramatically if you have a lot of bursty power efforts followed by relatively easy pedaling. If your mountain intervals are really rollers and you're killing the rollers, resting on the descents then I'd expect what you've described but then the key is to use your gears, and modulate your effort to make them as steady as you can. Your AP and NP shouldn't vary all that much on steady climbs...
So, what do you all do? Can I just watch my actual power and assume that on moment-by-moment basis that it is approximating NP? (haven't done the math on that one). Should I live in world of NP (FTP, etc. all done on NP) and only relate back to AP when using my PowerTap? Or does AP have some other use?..
Training levels are defined in terms of AP, especially for shorter efforts where NP is meaningless. Either work on steadier pacing during your intervals or find roads with more consistent grade and during training focus on RPE first and realtime power secondly (and loosely, don't glue your eyes to the PM and try to follow every change, you might also increase your PT display averaging to help avoid chasing your tail). And focus on AP when reviewing the data from individual intervals. Use NP as it was intended to estimate the overall stress resulting from the workout or race, for driving IF, TSS, CTL, ATL, and TSB.
Good luck,
-Dave
