NP values in PMC vs File



giannip

New Member
Jul 7, 2005
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Hi I'm sure I'm missing something simple but I noticed that my 20 / 60 min NP values for yestarday's file displayed in PMC is different to the peak 20 / 60 NP values in the file. I also have another chart in my athlete page where I track peak NP values for certain times. They match the PMC Is there a different way these values are calculated or whatbam I missing ??
 
Originally Posted by giannip .
...Is there a different way these values are calculated or whatbam I missing ??
I'm not sure of the specifics of what you're seeing but I expect it has more to do with the way the periods over which NP is calculated are selected. For instance there's no function in the ride file that selects the best 20 or 60 minute NP, instead WKO+ finds the highest AP for 20 or 60 minutes then also displays NP for those segments. It's entirely possible that there are other segments of the file that have a lower AP but higher NP.

Another possibility is that you're seeing NP for segments that span rest breaks in one set of charts and those are being filtered out in the other charts. Hard to say without digging into the data but FWIW I have seen small differences as in a watt or a few watts difference between peak NP reported for a given duration on a ride and what I see if I chart peak NP for the same duration in a custom chart. The differences have been so small and usually on the order of PM accuracy that I don't worry about it. If you're seeing much larger differences you could dive down into the data a bit to see what's happening and do things like break up files into smaller chunks or export the data to Excel for some data mining but again I wouldn't bother unless the differences are big enough to influence training decisions.

-Dave
 
Originally Posted by daveryanwyoming .




I'm not sure of the specifics of what you're seeing but I expect it has more to do with the way the periods over which NP is calculated are selected. For instance there's no function in the ride file that selects the best 20 or 60 minute NP, instead WKO+ finds the highest AP for 20 or 60 minutes then also displays NP for those segments. It's entirely possible that there are other segments of the file that have a lower AP but higher NP.

Another possibility is that you're seeing NP for segments that span rest breaks in one set of charts and those are being filtered out in the other charts. Hard to say without digging into the data but FWIW I have seen small differences as in a watt or a few watts difference between peak NP reported for a given duration on a ride and what I see if I chart peak NP for the same duration in a custom chart. The differences have been so small and usually on the order of PM accuracy that I don't worry about it. If you're seeing much larger differences you could dive down into the data a bit to see what's happening and do things like break up files into smaller chunks or export the data to Excel for some data mining but again I wouldn't bother unless the differences are big enough to influence training decisions.

-Dave
Thanks Dave

Well for yesterday's file (training race), the Peak 20min is 294 in the file but 313 in the PMC, while Peak 60min NP is 289 in the file and 298 in PMC.

I'd tend to believe the PMC figures more, taking into account I was in the break for the last 45min or so of the race.
 
Those are bigger NP differences than I've seen in the past. I'd probably poke around with the data in Excel to try to understand the 10 to 20 watt differences.

-Dave
 
Originally Posted by daveryanwyoming .

Those are bigger NP differences than I've seen in the past. I'd probably poke around with the data in Excel to try to understand the 10 to 20 watt differences.

-Dave
Will do. I'm wondering if I forgot to zero the unit before starting. I do it every tiime I use but that could be an explanation...
 
Originally Posted by Hunter w/kg .

Gianni- What build of WKO+ are you using? Make sure you have Build 48.
Hunter
Hi Hunter

Thanks for the reply. yep, both WKO+ & DeviceAgent are build 48.

I;ve looked at some recent figures in PMC and for example on the 1st, 2nd and 12th, the Peak 20min show is 307. Now I know I'm good at pacing ;-), but that also seems a little strange, while in the actual fils only one of those shows an NP of 307.

I'll monitor it over the week-end and email support if it persists. Maybe they can suggest something.