Right. And if both legs are providing a 30W difference in power in one position vs. the other, that might be worthy of investigation. Generally speaking, the pedal stroke should be reasonably symmetrical, excepting the well known swings in L-R power so popular to bring up in Stages threads. I guess it would depend on when and how the difference is occurring. But 5% is a reasonable threshold for raising an eyebrow. In my opinion.


Right....in my first post in this thread I think I said, "Get some Vector pedals to verify" with the unspoken intent being to get independent L/R measurement.


And that premise is based upon the premise of perfect unweighting of the rising leg. If some assymetry in timing, etc, is resulting in the rising leg actually exerting some sort of resisting force against the pedal, that would be *one* explanation for both legs providing 30W more power in one orientation vs. the other. And might be worth looking into.

Or you you could just shrug and say, "5%, whatever" and move on with life, and stop trying to explain data with no obvious answer. Which, odds are, is probably just fine in the grand scheme of things.

Dual-sided measurements + WKO4 FTW.

The basic physics principle applies whether or not one is pulling up or actively resisting. I never said anything about perfect unweighting, besides that's a red herring wrt to the power required to move legs up and down when they are connected to coupled cranks.

Whether or not it's worth looking into is not a judgement I think you can make with pseudo power balance data. It requires the right tools for the job.

Equally a pseudo power balance might report 50:50 which might initially suggest no further investigation required but in reality you may actually have a power imbalance that may or may not be worth looking into.

Can you see the problem?

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Possible even with 'true' balance measurements.

Looks like this may the correct answer.....part of the workout today included single-leg drills (I don't make the workouts, just ride 'em). The L/R balance from these intervals read as ~80/20 in favor of whichever leg was being used. Obviously since I was not using the other leg in these drills, the Quarq was interpreting the pull phase of my pedal stroke as power being applied to the other side.

Interesting....thanks for everyone's input.

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"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

I think that's a sub-optimal way to diagnose your potential problem. I'd bet your pedal stroke is a lot different when pedaling with 2 legs rather than 1. IMO, you can't just pedal with one leg and draw conclusions about pedaling with two legs.

Of course my pedal stroke is different with one leg vs. 2.....

Did you read my other posts on this thread? I know my right leg is stronger than my left, so the fact that my L/R balance comes out as 55%L and 45%R made no sense. Combine this knowledge with the data from today's ride and the insight from one of the smarter guys around re: power analysis and you can reach a logical conclusion as to why it reads that way.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

Just to be clear, all that the difficulty you have with your left leg using Powercranks is actually telling you is that you left leg hip flexors are a good bit weaker than those of your right leg. Your left leg extensors may in fact be stronger than those of your right leg. If this were the case the "pseudo balance" shown by your Quarq would show the pattern you're seeing.

YMMV,

Hugh

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Genetics load the gun, lifestyle pulls the trigger.

Yes, I have. To be blunt, I think you're wasting your time. The Quarq L/R data is not actionable data. It's neat to look at, but it's not measured independently, so it's nothing more than a novelty.

Just because you have a muscular issue with one leg, and you know it's stronger, doesn't necessarily mean your pedal stroke is imbalance as a result. I have a strength difference in my legs as well. I can do 10 pistol squats with my right, and 3 with my left, and yet my pedal stroke was measured as 49/51 during a 20' FTP interval on a set of Vectors.

If I was just looking at my PC experience, you may be right....but when you combine the PC experience with the end result of my lateral release (part of my quad is detached and I have a permanent 10-15% strength deficit), it tells a different story.

I'm not looking at just one piece of evidence and saying "Ah-ha!!".

Again, I'm not really concerned about the measurements....it was the fact that it was in such sharp contrast to what I am reasonably confident the reality is that I asked the question.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

I have a Dzero and a Polar M450, the head unit does not show Power balance, nor Polar Flow website, any one has the same issue?
It might be something wrong with the Polar BLE protocol, read somewhere on dcrainmaker comments.