Unusually high Power for a single trainer session

Jesmol
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Joined: Tue Feb 07, 2012 3:48 pm

Unusually high Power for a single trainer session

Postby Jesmol » Tue May 03, 2016 10:48 am

I'm trying to get my head around whether I have a strange power results for a trainer session I did last week, compared to this week and the prior weeks. To confirm the setup

1: Same Wind trainer (one of the ex AIS paddbleboat style things)
2: Same program
3: Very similar heart rate data
4: Slight improvement each week on speed measurement on the wind trainer sensor ( within a 1-2 km/hr)

Week 1 NP 221W , TSS 49 , Ave HR 161 , Ave Cadence 84, Ave Power 181
Week 2 NP 256W , TSS 68, Ave HR 158 , Ave Cadence 77 , Ave Power 217
Week 3 NP 211W , TSS 44 , Ave HR 159 , Ave Cadence 80, Ave Power 172

To me it would appear Week 2's power is not not consistent with the other 2 results.

dalai47
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Re: Unusually high Power for a single trainer session

Postby dalai47 » Tue May 03, 2016 11:00 am

I'd suspect an issue with the units calibration week 2...

Jesmol
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Re: Unusually high Power for a single trainer session

Postby Jesmol » Tue May 03, 2016 11:28 am

dalai47 wrote:I'd suspect an issue with the units calibration week 2...

Thats what I'm thinking, but there hasn't been a calibration between week 2 /3

dalai47
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Re: Unusually high Power for a single trainer session

Postby dalai47 » Tue May 03, 2016 11:37 am

Which power meter? Some auto calibrate when in use...

Jesmol
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Re: Unusually high Power for a single trainer session

Postby Jesmol » Tue May 03, 2016 12:45 pm

dalai47 wrote:Which power meter? Some auto calibrate when in use...

P2M

GJM
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Re: Unusually high Power for a single trainer session

Postby GJM » Tue May 03, 2016 1:31 pm

10% difference in cadence from week 1 to 2 is interesting.

It's most probable that it's just a quirk of the equipment.

But pushing a harder gear at lower cadence does, obviously, producer higher (but, for most people, less sustainable) power. So who knows, the cadence/gear might explain it.

Or are you certain that you were in the same gear/resistance on all 3 rides (if you were, then disregard the above theory :)

dalai47
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Re: Unusually high Power for a single trainer session

Postby dalai47 » Tue May 03, 2016 2:00 pm

I'm not familiar with the P2M calibration process unfortunately.

If you need to manually calibrate and you didn't between weeks (good habit to make sure the unit is calibrated for each ride), were conditions noticeably different (say temperature) on week 2 compared to weeks one and 3?

Jesmol
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Re: Unusually high Power for a single trainer session

Postby Jesmol » Tue May 03, 2016 2:28 pm

GJM wrote:10% difference in cadence from week 1 to 2 is interesting.

It's most probable that it's just a quirk of the equipment.

But pushing a harder gear at lower cadence does, obviously, producer higher (but, for most people, less sustainable) power. So who knows, the cadence/gear might explain it.

Or are you certain that you were in the same gear/resistance on all 3 rides (if you were, then disregard the above theory :)

Same gear IIRC , refining it down a little further, the final 5 minute interval looks like this

W1 NP229, Ave HR 169 , Ave Cad 75 , Ave Pwr 229 , Min Pwr 193 , Max Pwr 328 , min HR 163 , Max HR 176
W2 NP269 Ave HR 164 , Avd Cad 71 , Ave Pwr 266, Min Pwr 215 , Max Pwr 372 , Min HR 154 , Max HR 172
W3 NP224 Ave HR 166, Ave Cad 72 , Ave Pwr 221 , Min Pwr 152, Max Pwr 285 , Min HR 157 , Max HR 174

I recall that my ave speed from the WIND trainer was slightly higher W3 vs W2 , which would be explained by the slightly higher ave cadence.

Jesmol
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Re: Unusually high Power for a single trainer session

Postby Jesmol » Tue May 03, 2016 3:11 pm

I've had a look in GC at a power vs cadence scatter chart, there is a significant difference between the curves (note two gear ratios give two different curves). W1 and W3 are essentially the same, W2 has a higher response in power to cadence increases.

https://goo.gl/photos/fgEC4KDyFikKLWZn6
https://goo.gl/photos/V43dacYHjAo9wrHG8
https://goo.gl/photos/KfxtfoNmEoFGaQQx7

So either I did have the wrong gear set, or my P2M was reading high.

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Alex Simmons/RST
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Re: Unusually high Power for a single trainer session

Postby Alex Simmons/RST » Tue May 03, 2016 6:17 pm

Check and set the torque zero on your power meter every single ride.

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