I know there’s always the discussions about single vs dual sided power meters and leg imbalances which is the argument for dual sided power meters. I’m curious what people consider a significant imbalance? I’ve always been consistently 52L/48R with my power so I don’t consider that a big deal but I still like seeing the numbers from dual sided power meter
maybe 8-10%
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I’ve also got 52/48 split. So from our “n” of 2 it seems normal, but I always feel like it’s a lot. It’s effectively an ~8% difference, so let’s say your FTP is 300W then it’s like your good leg has an FTP of 312 while your bad leg is only at 288, come on bag leg! Let’s go! 
I’ve been running the Favero Duo’s on my gravel bikes (my main outdoor bikes) for nearly two years now and I’m almost always 55/45. No wonder the Stages single sided I previously had gave me some wildly inaccurate numbers compared to what I was used to seeing with previous power meters (PowerTap hub, Computrainer, Kickr, and Neo).
I’ve also got 52/48 split. So from our “n” of 2 it seems normal, but I always feel like it’s a lot. It’s effectively an ~8% difference, so let’s say your FTP is 300W then it’s like your good leg has an FTP of 312 while your bad leg is only at 288, come on bag leg! Let’s go!
Not that I’ve done a deep dive on my data but I look at a few rides from time to time and highlight some climbing and flat areas and I’m pretty consistently 52/48. Never varying too much outside of that. I do feel like it’s more important when I’m riding my tri bike or just in a triathlon to get my numbers right. On my gravel bike I tend to go more by feel than anything else.
One of these is a single-sided PM, the other is a crank-spider PM that reads both sides total power (but I don’t recall immediately which is which). The difference in the average readings is 4%, so is what you would get when comparing an average 52/48 (or 48/52) L/R imbalance with a PM that measured total both sides power.
… a 20/80 imbalance after a femur fracture became more and more balanced with the healing … in order to reach the last percent, the synchronous rhythm of the legs with the symmetrical position of the hips on the saddle were crucial and not attempts to push and pull more or less … oSo >>
I know there’s always the discussions about single vs dual sided power meters and leg imbalances which is the argument for dual sided power meters. I’m curious what people consider a significant imbalance? I’ve always been consistently 52L/48R with my power so I don’t consider that a big deal but I still like seeing the numbers from dual sided power meter
I imagine it depends on the type of riding you are doing. I ride in a city and there is a lot of stopping and starting with all the intersections. Since I tend to push off from a dead stop with the same foot, I sometimes get a large imbalance, larger than yours. If I’m on the trainer, I’m generally inside the 52/48.
So say you are more like 58/42, what should you do. I am assuming this could be a strength imbalance, or it could be leg length diferences. And I guess the question is does it really matter? It’s always been this way. Would focusing on fixing this make much difference? Like aero gains over a short TT.
I guess it depends.
Speaking from experience of always being 55/45 though, I’d try to get it addressed and see if it’s something that could progress into more. I’m dealing with some serious issues now with my low back that I’m having to do physio work for because of these underlying pelvic imbalances I’d kept pushing off.
Tested a few teammates for fun. The right footed people were right leg dominant and left footed were left leg dominant. Ratios were typically 52/48 or 54/46 for zone 2 riding. For zone 4 or 5 they all went to 50/50.
Had a 60/40 discrepancy for myself at zone 2. Found a loose cleat, tightened it, and ratio went back to normal.
As I really only care about my powers when I’m going hard, I’m quite happy to use a single sided meter. Compared two ss stages to a couple of powertaps and they were remarkably close. Very impressed with the gen 3 stages now, even for MTb and cx.
I mainly train on PE and correlate to power afterwards though.
Only thing I wouldn’t use a ss meter for is aero testing.
If you have a leg length discrepancy or have ever broken a leg or hip then I wouldn’t expect a ss meter to be anyway accurate.
Probably something appreciably higher than the degree of accuracy of your power measurement system.
It’s a problem when you can do a pistol squat for both legs
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No scientific clue. But, my anecdotal observation from comments here and my own experience is that I would judge anything more than 60/40 as “big.” But, that could still be normal.
Our bodies are not even remotely symmetrical. So, anyone with true 50/50 is probably an extreme outlier. Most of us are one-hand dominant, and we do not question the fact that our dominant arm is stronger and more coordinated than our non-dominant arm. I am right-handed and left-legged. I have kicked with my left leg since elementary school and have always known that leg was stronger. It came as no surprise to see a left power bias of 53/47 on my PM. (But what is surprising, is that I go to 50/50 when on hard climbs.)
Interesting that the person that can answer this question has been run off the forum by trolls.
So say you are more like 58/42…and I guess the question is does it really matter?.. Would focusing on fixing this make much difference? .
I doubt it matters much, I doubt focusing on this would fix it. The 2 questions that pop into mind are
- what do I lose if I fix it during the period it’s going to take me to retrain myself
- what sort of long term gains can I expect? (if any)
I snipped this part what should you do. I am assuming this could be a strength imbalance, or it could be leg length diferences.
If you don’t know then you can try to fix it via pathway A only to make it worse when pathway B would been the correct pathway to fix.
In running we know it takes about a year to make a change in your running form stick and most people can won’t get any faster in race times during that year and there isn’t a ton of evidence that shows making changes = improved performance. Sure you’re going to get a lot of people that say well I was running faster after I switched to this or that. Yet, there are so many variables involved it would be hard to say.
What I would suggest are focus on the factors that increase performance and if you feel like a small imbalance is the thing that is holding you back then figure out how to fix that. My guess is 58/42 is less of an issue than a lot of the things that impact performance like to choose something, O2 delivery & uptake.
I started using a dual sided pair of Garmin Vectors in 2013. I currently use the latest Garmin Vectors and the power imbalance is something I have long worked on. When I first started looking at the imbalance I would often see 60/40 or even 70/30. I thought the power meter must be inaccurate but realized it immediately would record 50/50 when I stood up. I have been riding and racing for many years and it was concerning. My right leg had an ACL graph and cartilage damage. My right leg was shorter than my left and a shim helped with the power imbalance. I often start to favor my left when I get tired. I ride with the balance figure on my head unit to keep any eye on it. I know that I have to feel my right and try to drive through the ball of my foot. When I do this, I can immediately see the change in the balance figure and I can feel my right glute engaging more. I have improved the imbalance and now float between 55/45 on a lazy day and 52/48 on good day. Flatter rides are when the imbalance is highest as it easy to let one leg overwork when the speed/cadence is higher. When I look at the power stroke data I can see where I will often start the left power stroke before TDC and the right after TDC the degree to which this happens often dictates the power imbalance. I think getting a video of yourself on a trainer may help you identify if you have any strange hitches in your pedal stroke. I know when I allow the power figure to drift left, I start getting strain in my left knee as I get later in a ride.
…When I first started looking at the imbalance I would often see 60/40 or even 70/30. I thought the power meter must be inaccurate but realized it immediately would record 50/50 when I stood up. I have been riding and racing for many years and it was concerning. My right leg had an ACL graph and cartilage damage. My right leg was shorter than my left and a shim helped with the power imbalance. I often start to favor my left when I get tired. I ride with the balance figure on my head unit to keep any eye on it. I know that I have to feel my right and try to drive through the ball of my foot. When I do this, I can immediately see the change in the balance figure and I can feel my right glute engaging more. I have improved the imbalance and now float between 55/45 on a lazy day and 52/48 on good day. Flatter rides are when the imbalance is highest as it easy to let one leg overwork when the speed/cadence is higher. When I look at the power stroke data I can see where I will often start the left power stroke before TDC and the right after TDC the degree to which this happens often dictates the power imbalance. I think getting a video of yourself on a trainer may help you identify if you have any strange hitches in your pedal stroke. I know when I allow the power figure to drift left, I start getting strain in my left knee as I get later in a ride.
Injuries such as yours are one of the few known places where L/R balance has application.
Do the leg press machine at the gym and see if there’s a difference between strength in the legs. If there is, do lots of one legged exercises in the gym to try and get the strength equal.
Did you play soccer or basketball earlier in life? Those sports can lead to leg length discrepancies.
One legged pedal drills might help too. I usually do those on the trainer. They’re doable outside, just a little harder.
I started using a dual sided pair of Garmin Vectors in 2013. I currently use the latest Garmin Vectors and the power imbalance is something I have long worked on. When I first started looking at the imbalance I would often see 60/40 or even 70/30. I thought the power meter must be inaccurate but realized it immediately would record 50/50 when I stood up. I have been riding and racing for many years and it was concerning. My right leg had an ACL graph and cartilage damage. My right leg was shorter than my left and a shim helped with the power imbalance. I often start to favor my left when I get tired. I ride with the balance figure on my head unit to keep any eye on it. I know that I have to feel my right and try to drive through the ball of my foot. When I do this, I can immediately see the change in the balance figure and I can feel my right glute engaging more. I have improved the imbalance and now float between 55/45 on a lazy day and 52/48 on good day. Flatter rides are when the imbalance is highest as it easy to let one leg overwork when the speed/cadence is higher. When I look at the power stroke data I can see where I will often start the left power stroke before TDC and the right after TDC the degree to which this happens often dictates the power imbalance. I think getting a video of yourself on a trainer may help you identify if you have any strange hitches in your pedal stroke. I know when I allow the power figure to drift left, I start getting strain in my left knee as I get later in a ride.
How much more power do you put out on a good day VS a lazy day?