I also purchased "Training and Racing with a Power Meter" 2nd edition by Hunter Allen & Andrew Coggan on recommendation by Alex Simmons in another post. Can not recommend this book highly enough. It just makes so much sense to me.
My main question is displayed the "power" data on the Garmin as mentioned by Alex in another post:
Alex Simmons/RST wrote:1. on the road, power output is highly variable, and is the first thing people notice when they see it on a bike computer for the first time (or when they inspect a power meter file)
2. there is a mathematical artefact of the way the Powertap calculates data, which exacerbates the variability in the second to second data. It isn't an accuracy problem (on average). The issue is caused by the fixed duration sampling of the torque data, which results in an effect known as "aliasing". It is more noticeable at certain cadences over others. I can explain more if anyone is interested.
3. to help reduce the "signal noise", it is useful to set the display to show a rolling average power, usually something like a 5-second rolling average tends to reduce the variability in the second to second data somewhat. over time, if you are using the meter to guide say an interval effort on the trainer, then you get pretty good at doing a running integral in your head and not concern yourself with the ups and down of the more instantaneous data but rather focus on the overall effort level.
The Garmin 705 gives you three options:
1: Current Power
2: Power averaged over 3 secs
3: Power averaged over 30 secs
Current Power as Alex said, bounces all over the place one second 200w next 400w.
Averaged over 3 seconds is not much better still bounces up and down.
The next time I ride, I am going to try 30 sec average, because I want to concentrate on overall effort and not what power I am generating right now. I don't want to know how much a power I am generating during a fifteen section sprint, otherwise I am not working hard enough. I rather try and keep riding in a certain range over a much longer time span.
So how do other people manage this?