Thread: Power Meter
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Old 04-26-14, 10:25 PM
  #115  
gregf83 
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Originally Posted by achoo
I'm curious about this test - in theory, an SRM with its high sample rate should be able to pick up power asymmetries. And topping out at 350W really isn't a high power level - but it looks like only 6 out of 10 cyclists in the test could hit 350W. How good are the cyclists in the test? How long did each test run?

So the test seems to be blowing cyclists up? It doesn't really matter what happens to your power when you blow up, cuz you get dropped.

And I also note that this test doesn't claim the dominant pedal changes from side-to-side for any cyclist.
The problem with the SRM is that it can't separate the torque from the left and right pedals regardless of its sampling rate. The SRM can't tell if you're pushing down with your right or pulling up with your left leg. This is illustrated in fig 2 above.

The data was from a step test 25w/min increases.

What the data shows is that for this group of cyclists their asymmetry changed significantly with power and the asymmetry can be quite high. At 300W the asymmetry index(AI) was 36%, equivalent to a 41/59 split. The AI wasn't consistent with changes in power. Other studies have also found changes in AI with fatigue during the course of a time trial. That could make pacing based on power difficult.

Last edited by gregf83; 04-26-14 at 11:05 PM.
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