Normalized power interpretation question

[DRAwpt]

I did a workout with some guys last night where we climbed some really steep (up to 15% grade) short climbs (some as short at 50 m, some as long as say, 300 m).
Using cyclingpeaks 2.0, I found the duration to be 1 hour 27 min, with an average watts of 189, and a normalized wattage of 316, IF of 0.988 and VI being 1.67 (which seems high). My best hour was 215 W average with NP of 342, IF of 1.068 and VI was 1.59.

I've been using an FT of 320 Watts. A few days ago I did a TT, which is normally my strength, and was only able to average 306 W for 19 km. One caveat was that I changed my position to a more agressive one, and I believe it was too low in front and my seat was too low and far back. I will be doing some TT specific stuff in the next few days, so I'll hopefully see better wattage there.

SO... my question is whether the steepness and shortness of the hills I did skewed the NP to make it appear that my FT is higher than it is, or should I maybe bump it up a bit. I know I shouldn't base too much on one workout, but I am anxious for signs of progress.

Thanks in advance.

 

[wilmar13]

what Power measurement device do you use?

 

[otb4evr]

<snip>
SO... my question is whether the steepness and shortness of the hills I did skewed the NP to make it appear that my FT is higher than it is, or should I maybe bump it up a bit. I know I shouldn't base too much on one workout, but I am anxious for signs of progress.

Thanks in advance.

I would leave the FTP where it is. My thought is that as long as you are "in the neighborhood" of your correct FTP, it shouldn't matter. The signs of progress you should be concerned with are the ones that will tell you how you are doing in relation to your riding/racing.

Are you able to go harder?

Do you recover faster?

How are you doing in relation to the others in your group/category?

Are you able to carry more wattage over the same time/hill/interval vs. last month?

If you are concerned that your FTP is getting really out of whack, test and find out.

BTW The only reason I consider FTP important is that I track TSS... Approximations, within 10 - 20 watts, seem to do just fine for that.

During races, I go as hard as I can/need to.

HTH,

Jim

 

[frenchyge]

SO... my question is whether the steepness and shortness of the hills I did skewed the NP to make it appear that my FT is higher than it is,

It's quite possible, although another possibility is that the extra motivation from the other riders helped produce a breakthrough performance, and the power is legit. I would suggest conducting a good test on a fresh day or checking this workout's NP against a couple of the other FT 'estimating' methods to try to correlate the result.

I know I shouldn't base too much on one workout, but I am anxious for signs of progress.

That's exactly right -- be patient. When your performances start to consistently imply a higher FT, then that's the time to change it. What matters most is what you can do when the chips are down.

 

[acoggan]

I did a workout with some guys last night

(snip)

My best hour was 215 W average with NP of 342, IF of 1.068

(snip)

I've been using an FT of 320 Watts.

(snip)

SO... my question is whether the steepness and shortness of the hills I did skewed the NP to make it appear that my FT is higher than it is, or should I maybe bump it up a bit.

I would say that depends on how you established that 320 W value in the first place, and hence how confident you are (were) in it. If you felt that the value was rock-solid, then your ride last night may simply have been an "NP buster".* OTOH, if you're a little unsure of the 320 W value, then last night's ride could indeed be considered evidence that your functional threshold power is really higher than that (but not higher than 340 W).

*Personally, I think that even if you "busted the algorithm" by exceeding the +/- ~5% tolerance limit usually seen, the algorithm still performed remarkably well. Think about it: you pounded out a hard ride where your power was so variable that your average power was only 2/3's of what you can sustain in a steady fashion, yet the normalized power was w/in 6.8% of your functional threshold power.

 

[peterpen]

Short (but over 30") steep hills done flat-out will give me very high NP readings. I've seen NP 40w> than my FTP for ~60' races with 10 laps of circuit including a 17% pitch. (This is one reason why I don't see any need for real-time access to NP #'s.)
I start to wonder if my FTP needs adjustment when I *consistently* see high IF's (and therefore NP) over a variety of rides/ races.

 

[RapDaddyo]

I think a match analysis of your ride would be very interesting. I'm guessing you burned a lot of matches with short, high-power segments at or near VO2MAX. So, your AWC was probably exploited fully and repeatedly. Some TTs could bring out the same type of power profile, in which case the NP for your ride would be valid for planning the TT target NP. But, I would use a more constant AP performance benchmark to plan a flat TT target NP, which may well be lower.

 

[DRAwpt]

I think a match analysis of your ride would be very interesting. I'm guessing you burned a lot of matches with short, high-power segments at or near VO2MAX. So, your AWC was probably exploited fully and repeatedly. Some TTs could bring out the same type of power profile, in which case the NP for your ride would be valid for planning the TT target NP. But, I would use a more constant AP performance benchmark to plan a flat TT target NP, which may well be lower.

I did a match analysis, and found 9 matches (using the method found in the book to identify them through fast find). I definitely blew on the second to last one, and again about 75% through the last one.

I've included a copy of the file for anyone interested. I use a Powertap Pro for training and Powertap SL for racing. I've zeroed each of them in the last 5 days.

 

[DRAwpt]

I would say that depends on how you established that 320 W value in the first place, and hence how confident you are (were) in it. If you felt that the value was rock-solid, then your ride last night may simply have been an "NP buster".* OTOH, if you're a little unsure of the 320 W value, then last night's ride could indeed be considered evidence that your functional threshold power is really higher than that (but not higher than 340 W).

Last year I did several 20 km TT's in a lab study where I averaged up to 330W on a Velotron. In February, I did another one (a 30 minute TT), this time as part of a fund raiser at our gym, this time on a Computrainer, which was calibrated against a Powertap, and I did 331 Watts. This gave me an estimate of around 315 Watts for my LT wattage. I have been feeling pretty strong, especially after a mountainous training camp in Italy, so I have felt ok about using 320 as my LT wattage (more or less equivalent to FTP, no?).

The last TT I did was a 19 km, for which I was happy with the speed (43.5 kph), but not with the watts (306 average). It was a windy day with rain, but I would have liked to have seen an average closer to 320. Like I said in my original post, I played with my position the night before the TT (my bad...I know), and may have lost some watts there.

 

[ric_stern/RST]

...for my LT wattage. I have been feeling pretty strong, especially after a mountainous training camp in Italy, so I have felt ok about using 320 as my LT wattage (more or less equivalent to FTP, no?).

To clarify, this is unlikely to be the power that elicits your LT. Lactate threshold, (although there are a couple definitions) is the work rate that elicits a 1 mmol/L increase over exercise baseline levels (giving a lactate of ~ 2.X mmol/L) or the work rate that elicits a fixed lactate of 2.5 mmol/L. These are ~ 10 - 15% less power than that which can be sustained for ~1-hr, and consequently can be sustained for up to ~3+ hrs.

Ric

 

[AshesGlory]

I did a workout with some guys last night where we climbed some really steep (up to 15% grade) short climbs (some as short at 50 m, some as long as say, 300 m).
Using cyclingpeaks 2.0, I found the duration to be 1 hour 27 min, with an average watts of 189, and a normalized wattage of 316, IF of 0.988 and VI being 1.67 (which seems high). My best hour was 215 W average with NP of 342, IF of 1.068 and VI was 1.59.

I have seen something similar. I have a PT-SL. Using various testing protocols - 2x20min, 95% of CP20, monod CP analysis, I see a pretty consistent FT estimate of 300W. However a workout I did last week comprising warmup, 30sec sprint intervals with 3min rbi, lasting 60 mins, my NP was 325W. This corresponds to my season max AP for a 10 minute duration, achieved during a break in a hill climb race - a pace I could not maintain for 11 mins, never mind 60 mins. So I am also quite sceptical that this NP number represents my FTP.
OTOH the high TSS registered by this short w/o seemed quite apt given the way i felt for the following 24 hrs.