No Polar Power readings below 30s duration?

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I'm using a Polar power sensor and CP software, and I've noticed that I get almost no readings in the 5s or 10s duration.

Is this just becuase the Polar not only has the weird averaging thing going on, and then only records at 5s anyway? Or, is there something wrong with my setup?

Any assistance much appreciated.

Regards,
Richard.

I'm using a Polar power sensor and CP software, and I've noticed that I get almost no readings in the 5s or 10s duration.

Is this just becuase the Polar not only has the weird averaging thing going on, and then only records at 5s anyway? Or, is there something wrong with my setup?

Any assistance much appreciated.

Regards,
Richard.
What do you have the recording rate set at on your watch?
The polar is not very useful unless you set it at the minimum of 5 seconds.

I figured the record rate thing early on - I have it set to 5s. I have noticed that from a standing start, the my Polar Power sensor takes between 5 and 10 crank revs to work out the power - I read about it wierd averaging algorythm somewhere.

I'm using a Polar power sensor and CP software, and I've noticed that I get almost no readings in the 5s or 10s duration.


Can you explain this a little more? I'm having a hard time grasping what you're meaning. When you look at the plot of your power file in CP, isn't there a power number every 5s while pedalling?

...or, do you mean the your 5s and 10s average power values seem low?

If that's the case, then yes, it's a function of both the averaging scheme AND the recording method. Approximately every 2 seconds the watch displays a weighted average of the last integer number of pedal revolutions since the last calculation. Whatever number that's in the display is then saved once every 5 secs. This scheme can result in short peaks being "missed" or diminished in the recorded file.

Please help me understand...

I've noticed that it takes my Polar unit about 20s to reach a 'true' stable ready when I'm doing intervals, but once I'm at a 'steady state' the readings are pretty much OK.

CP software seems to pick up my 5s and 10s efforts (but they never seem high enough :o )

From what I've read on this forum and other places, the Polar isn't great (useless :confused: ) for hard, short duration efforts and my experience (on a trainer where it lives semi permanently) is that that's pretty much the case, but for long efforts/intervals (5:00, 10:00, 20:00 etc) its pretty good.

I've discussed the averaging algorithm with Polar - or, that is, I've asked and they have refused to discuss how they calculate. Nor will they discuss the contents of their files in detail.

Given that they bundle the software with their products, it seems odd they they consider them proprietary. It's not like they would lose sales if someone decided to buy another software package to use with their Polar.

"Secret" calculations appear to turn away customers rather than retain market share.

Tom asked for a better explaination of what I'm seeing.

In the CP software (WKO+), I do see power readings in the 5s and 10s bins, but the values are very low, or perhaps my legs are always very weak :(

I would guess that the power sensor is missing all these short duration power peaks. Sounds like this is a common experience.

For the longer durations, 30s or more, I think the readings are more accurate, it's just these short peaks that seem to be 'averaged' out.

R.

Tom asked for a better explaination of what I'm seeing.

In the CP software (WKO+), I do see power readings in the 5s and 10s bins, but the values are very low, or perhaps my legs are always very weak :(

I would guess that the power sensor is missing all these short duration power peaks. Sounds like this is a common experience.

For the longer durations, 30s or more, I think the readings are more accurate, it's just these short peaks that seem to be 'averaged' out.

R.

I see...yes, as I said above, this is a known characteristic of the Polar averaging/recording scheme. For a good example, see the following under "Peak Power":

http://biketechreview.com/archive/pm_review_2.htm

In reality, it's not that big of a deal (IMHO). You aren't going to be using the PM to "gauge" your effort during sprint workouts. Those are "pedal to the metal" anyway...it's just that you won't be able to quote as high of peak power outputs as your PT, SRM, or Ergomo sporting brethren. Oh well, that'll just make them feel worse when you smoke 'em with your massive 700 watt sprint ;)

You aren't going to be using the PM to "gauge" your effort during sprint workouts. Those are "pedal to the metal" anywaySo, how do you measure the benefits of focused L7 efforts?

So, how do you measure the benefits of focused L7 efforts?

Race results ;)

...or, city limit sign sprint competitions. :D

Seriously, although the 5 sec and 10 second results can be reported "low", most of my L7 work is done with 20 to 25 seconds intervals. I've found the results to be rather repeatable and I'm able to measure improvement despite the fact that the peak power readings (and the overall average for the interval) are somewhat attenuated.

I'm just looking at lower numbers, but the results are still the same.

Nor will they discuss the contents of their files in detail.Google is your friend:

http://daveb.net/s710/src/s710/doc/README.file_format

Also, a lot of their display and recording averaging methods are of public record if you search the "usual suspects" forums (i.e. Topica Power and here) and information is also available in their US patent filing which of governmental public record.

Enjoy!

Berend