Leg imbalance - whats the cure?

I was looking for some guidance. Every time I get towards the end of the cycling season (leisure only!) my right leg is considerably bigger than my left. This year, I have started using a left side only power meter (Garmin V3). What I have noticed is that if I focus on my left leg pedalling (kick over the top, pull across the bottom) there is a massive increase in the power. No matter how hard I try to keep both legs doing the same work, as fatigue kicks in the right leg takes over the workload. This can be seen in that my cadence, gear and resistance stays the same, but the power drops, meaning the left leg (with the power meter) is doing less and the right is working harder to maintain.

At the end of last year I did get my wife (who is a chartered Physio) to measure leg length, and the right was a bit shorter (about 7mm) whether it is bone length or bio mechanics is an unknown, meaning it had to flick down a bit further at the bottom of the stroke, leading to a dipping hip! I added a packer between the cleat and shoe (3mm) to compensate and things have improved.
Last year, I was mainly in the gym with little cycling, so both legs are even and strong, but from 4 weeks on the turbo in Jan, I can already see the big right leg appearing, despite the packer

What Advice is out there fore correcting this pedalling technique. I read that a fixie may help? I’m OK with an imbalance of sorts, but this appears to be quite a lot! I have only a single sided meter as I say, so I have no data to back up “quite a lot” other than gut feel, leg size and fatigue feel.

thanks in advance people! :+1: :biking_man: :biking_man:

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Sadly I’ve no idea my left leg is stronger than my right 57/43 despite having an arthritic left knee. Stumps me. I’d have thought it should be the other way round.

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My legs have no imbalance but I see the same - applying power smoothing to 3-5 seconds or longer should reduce the symptoms.

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My right used to be significantly larger than the left. Like you it was a bit shorter, the Shim seems to have balanced it out over time. The right is still stronger but the FTP is set with the left though and as I’m training to that there’s no real issue, maybe its reading a little low but its constant :+1:

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My legs have had a significant strength imbalance and a visual difference in muscle size for as long as I can remember. I started training with a Stages single-sided powermeter in 2016 with the assumption it’d help make my weaker left leg stronger. It seemed reasonable to assume a weak leg was an easy gain for power improvement. 4.5 years later the imbalance is the same as it ever was and the legs still look slightly different. At this point it’s no longer a concern for me- just one of those quirks I accept in my body. Have you had a bike fit? Is it holding you back? If it is, address it. If not, maybe, to an extent, ignore it.


Perhaps what he’s hoping for is that if he can trick the weak leg into doing it’s share, he’ll gain some “free” watts. Ignoring it would leave those watts on the table.

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Or get a double sided power meter so it also records power from the strong leg?

My personal opinion is that the only way to really assess is to get a dual sided PM and see a great bike fitter.

About 1.5 years ago I went to a really good fitter just for a checkup and it was eye opening. I had a leg length discrepancy, but also my pelvis is tilted which over compensates for the length difference. We ended up moving my saddle and handlebars a little which ended up giving be better leg extension on my ‘strong’ leg. No shims and no side-to-side saddle rotation required. I got a dual-sided PM mid-way through and it turns out my perception of the L/R balance was way off. My ‘weak’ leg was actually working harder than my ‘strong’ leg, which is why it was giving up earlier.
One thing I found amusing and liked about the fitter I went to, is he kinda looked at me like a puzzle to figure out, understand and fix. It was a little weird at first but I appreciate that he took the time to understand my biomechanics and apply his knowledge to help me achieve a more comfortable and powerful position.

That you get hypertrophy with one leg is interesting. I don’t think it is unreasonable to think there is something going on. Something that a dual-sided PM might show is that your ‘weak’ leg is actually doing more work than your ‘strong’ leg, which could be why it fatigues early. But that wouldn’t explain the hypertrophy. It would be interesting to see if the strong leg is actually growing bigger or if the strong leg stays the same size and the other slims down.

My other post about a dual-side PM was tongue-in-cheek. I was not trying to make fun of you or your situation. It could be useful to assess L/R balance in an objective manner rather than subjective feeling, and you might also get higher power values sent to your head unit. Is that a win-win?

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I have it it at a 3 second average. It can jump from 145 to a constant 160 with the same effort.

That would be a win win. Thanks for the info. I have a good bike fitter that I went to about 4 years ago he is cyclist who almost make it as a pro, and is now a physio. Once lock down is over I’ll pay him a visit.

Thanks Sean. No, it doesn’t hold me back. Lack of power does that! It does not concern me as such, but I do not want to have issues (hip or knee for example) from over working one leg. Thanks for your input.

As far as I can tell, isolated leg drills to activate the muscles and concentrate like hell on pedaling from the core.

What I mean about “pedaling from the core” is that if your core isn’t balanced and strong, your extremities won’t be either. When the core muscles are strong, balanced (left right front and back) and engaged, your legs have an equally good base to initiate movement. The whole system is connected! Everything really does hinge on the core.

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ortho shoe inserts to make up the difference?

weights? single leg/side exercises such as single leg box squats?

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You may want to surgically swap your left and right legs so that your left-only powermeter reads your stronger leg.

Instant FTP increase!



Haha this is nothing to joke about :wink: I had a left only PM for my first year of “proper” training… Feeling great and good numbers…

then last year I got a Quarq PM, and all my PRs disappeared since there was a 52/48 balance in my legs, so had magic watts appearing for awhile there :frowning:

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52/48!!! You were lucky :smiley: When I got a 2 sided PM I found mine was 54/46 and my FTP slipped 12% overnight. On the plus side I then realised why I so much slower up the hills than I that thought I should be. Now I just know I’ll be slow.

And why my right side lay-ups are so much easier than my left side lay-ups. And why my volleyball coach 20+ years ago couldn’t fix my goofy footed approach to hitting.

But yeah, my 10% drop in power on April 14, 2020 (a day that will live in infamy) sucked. At least with a year of hard work I’ve reset all my bicycling PR numbers. My basketball and volleyball improvement window is long closed. :slight_smile:

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Tweaking your position might change things, but one-legged pedaling drills almost certainly won’t.

The bigger question, though, is why you want to fix what doesn’t seem to be a problem?

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The thing I don’t understand is that my strongest leg comes complete with an arthritic knee.

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Its took time for me (I had a heavy leg imbalance where the right was far stronger). Shims I think have balanced it out eventually (although my right still feels stronger to a degree).

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