Pushing more Watts through left leg at high cadence

I note that I am pushing 15W more through left leg at high cadence compared with low cadence.
Is this normal?
My HR is definitely spiking higher (10bpm higher) at high cadence so more fatigue, and the Right leg is perhaps struggling then?
Wondering whether I should do single leg drills to strengthen the Right leg. Any hints/ideas?

Did a Gorby workout (Zwift) running 4iiii LHS and Wahoo Kickr.
5x5min of around 55%/110% FTP.

At high cadence and high power (95-100 cadence, 275W), the 4iiii was consistently showing 300W. At lower cadence (70-75), the 4iii power comes down to 275. Showing me that left leg is pushing 150W at high cadence and 137W at low cadence. A 13W diff between high and low cadence.

At high cadence and low power (95-100 cadence, 135W), the 4iiii was consistently showing 170W. I did not check at lower cadence (70-75). Showing me that left leg is pushing 85W at high cadence vs theoretically 67.5W (A 17.5W diff between high and expected output).

There’s always some discrepancy and it almost always occurs in various zones. My left leg is more dominant at lower power and at threshold and up I’m close to 50/50. It’s good to know but not really something I’d concern myself with to actively fix.

Your legs are almost never identical in length either, so…


There will be variation all over the place. Even in a relatively easy power band, there will be variance.

Sample of my weekend ride at an easy upper Z1, low Z2 range. Cadence varied from 60-90 rpm, and as you can see from the scatter plot, it’s all over the place. There are areas of proximity that happens more frequently, but it is going to vary.

From an Assioma DUO.

I am going to try to address my imbalance during this off-season. It didn’t use to be this bad. I push more on the right, and am right foot dominant to begin with.

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