Hoping someone can point me in the right direction.
For some time I’ve been suspecting unusually low NP numbers after my rides.
Today this was confirmed when I was doing a seated sprint session, and when pressing the lap button after my interval, my NP for previous lap was almost half the power I was holding for the duration of the effort. I clearly recall this being way higher and very close to average power when doing this workout previously.
I’m using Garmin Edge 520 and Power2max NG eco.
Can this be a Garmin device issue or PM issue? How would I go about troubleshooting this? Can’t find anything on the internet.
The data fields below is showing max power, average power and normalized power, in that order.
For very short intervals normalised power will be much less than average. The calculation starts with a 30 second moving average so your 19s intervals will include quite a bit of time before at much lower power. You can see this on the “30s Power” chart, though its not quite the same since that chart uses a centered moving average.
NP won’t be accurate for any interval within a session, just for the session as a whole. Your decoupling data will also have slight inaccuracies because of this algorithm. It’s a pity.
From what I can make out, Garmin employ the same calculations.
Personally I’d much prefer it to be like TP but it is what it is and gotta just go with it.
Hi @david
Is there any chance that NP calculation method could be revisited so that NP is based on the interval itself, like on TP?
I only ask because comparing NP to average power is an excellent way of determining the quality of execution a given interval.
Last night as an example I did a 4x8 at 300w. Training Peaks and my Wahoo reports an average 300w for each interval and also a NP of 300w for each one.
But Intervals is showing values of 299 for each average and 297 for each NP and these values are incorrect. If I didn’t have TP to verify against then I might be left wondering why I didn’t execute the interval correctly.
Thanks
Doing 297W vs 300W is not incorrect, and it won’t affect performance either way.
I get that you’d like to see NP being shown “correctly”, but if you understand how the intervals are calculated in both TP and Intervals then you will know how to compensate for it. I’m also not saying David shouldn’t change it, but he has set it up as 30s rolling average.
Doing 297W vs 300W is not incorrect, and it won’t affect performance either way.
Oh I know. I’m not suggesting it is. But what I like to see in a a properly executed interval is the average and normalized watts marrying up. If I happened to do an interval that TP reports as 302 NP with 300 average, my fear is that that difference might be reported as even greater on Intervals and end up with a 5w reported difference. Then you’d be wondering if it was executed as well as could be. I’d eb wondering if my power throughout was maybe a bit all over the place. Easy to happen on undulating road or gusty wind conditions.
I get that you’d like to see NP being shown “correctly”, but if you understand how the intervals are calculated in both TP and Intervals then you will know how to compensate for it. I’m also not saying David shouldn’t change it, but he has set it up as 30s rolling average.
There is no way to compensate for this other then increase the watts in the last 30 seconds of a recovery interval. I am not, nor will I ever, be prepared to do that in order to get numbers to marry.
I fully understand what you want to do, but doing an interval outside is even harder than inside. Average power will drop the second you free wheel, which is a normal thing outside, and can also happen inside if you are shifting gears.
There are a few podcasts that have hit the air in recent weeks where the central message is not being able to see the wood from the trees. Too much detail can detract from the overall intention of the session.
Ya. Agreed. Just to clarify though, I fully understand that a 3x10 at 297 will produce the same physiological response as a 3x10 at 300 and I’m not arguing that at all. I’m not getting caught in the fine detail. Ultimately I know when my intervals are executed correctly and that is what really matters when all is said and done.
But there are other considerations…
The NP reported for shorter intervals on this site are incorrect. There is no getting away from that fact. It’s indisputable.
People have different mindsets. Not right, not wrong, just different. Some of us are very black and white. It drives me mad that a perfectly executed interval is not accurately reflected in the data. Others couldn’t care less, and that’s fine too. But when I do an interval of 10 minutes at 330 watts and I know it’s bang on the whole way through, it drives me crazy to see that reported as an average of 329 with a NP of 327 on this site. Bananas.
All the above said, I do accept what we have here is a fantastic resource at a fantastic price. Am I willing to switch back to €100 euro a year for TP over €40 for Intervals. No, I’m not. Nonetheless it’s still irritating that some data is not reported correctly. If it’s something that could be corrected then I think it should be corrected.
As as aside - If I’m doing an 8 or 10 min interval outside, I ain’t freewheeling
What podcasts do you listen to @Gerald that you’d recommend? Fast Talk ? Ross Tucker’s Science of Sport is also v good
Tuesday was 4x8. Each reported average on Intervals was 299w and each reported NP was 297w.
Training Peaks reported each average and NP as 300w
I’m after going back and randomly picked a session from 2021. Massive differences.
3 minute intervals. Intervals.icu reporting a 10 or 11 watt difference between average and NP for each. Training Peaks reports 1 watt difference.
Picking one of the 4 as an example - Intervals.icu Average 392 with a NP of 383. Training Peaks reports average of 394 with NP of 393. This is the issue with the calculation method used here. If someone doesn’t have actual correct data (i.e. that from TP) to compare to you’re going to be left wondering if you were on top of the power properly the whole way through or if your power was a bit all over the place. A reported 11 watt difference between average and NP for a well executed 3 minute interval is just nuts to be honest. It in no way reflects the execution of the interval and is just incorrect data reporting.
Obviously the shorter the interval and the higher the watts the more pronounced these differences will be. But I don’t think it’s unreasonable to expect that for intervals of 3 minutes or greater we should have correct Averge/NP reporting
I haven’t found out yet how TP does the calculation of NP for lower duration intervals, but if they come up with a different number, they are not ding it ‘correct’ following their own definition of NP. They probably use some workaround for shorter intervals, hence my feeling that you are giving this too much attention…
I’m not trying to convince you of accepting, just saying that the calculation david is doing, conforms to the definition of the NP parameter.
How are you measuring your NP in your activity data? Where does the interval start and finish?
Which data are you looking at to get the Normalized Watts and Ave.Watts?
Here is one of my intervals:
I use the Raw Power first, along with (an expected) change in cadence. The W’ can also work if it’s above threshold. This is 5 minutes, so as @MedTechCD has said, below the value TP would deem “adequate”.
WKO and Intervals both import the raw data. I agree that the calculation is not ideal, which is why the raw data is better to look at. I don’t have a premium TP account, so can’t view the lap data.
WKO reports a different value to TP; Tim Cusick (WKO Product Leader) has mentioned this many times too, due to the way TP collects data. The data in Intervals and WKO match 100% (for my data, and also of those I coach that upload to TP>WKO). This is important for me, and the athletes I’m working with. I prefer WKO for some stuff and I prefer Intervals for other; it’s complimentary. Knowing that the data matches in these two apps ticks the accuracy/validity and precision/reliability boxes.
