Hey folks,
I always see a 54%-46% or 47%-53% left/right power balance after each ride (a year’s worth of data).
I am thinking it might stem back to a football injury I suffered when I was 20 - an ACL injury which required a reconstruction.
Is this unusual?
If so, is the imbalance big enough to worry about…?
It’s not unusual. Don’t worry about it.
YMMV
Hugh
I’ve had nagging knee issues the last year.
A few weeks ago I propped myself up on a wall like a wall sit and noticed my right thigh looked atrophied compared to my left, and sure enough, there was almost an inch difference in the size.
I pulled up my power balance and set it as a field on my Garmin and it was skewed around 54-46%, so since then I’ve been steadily working on having an equal balance. There was definitely some strength differences. Last week I finally did an hour with 50/50, and without concentrating on it I’ve been getting more consistent 51/49.
I think doing that plus some targeted strength work in the gym has definitely improved strength. I’m hoping that translates into improved knee function as well.
It’s not necessarily unusual but whether it’s enough to worry about and address is individual. I’ve had an imbalance I dealt with for 20+ years on the bike that didn’t affect me much at all. I’ve now spent the last 18 months in and out of training and in and out of physical therapy trying to address major SI joint pain that the imbalance (and training with it) has caused.
I was previously of the mindset that it’s not worth worrying about, but I’d change that if I could go back in time and ensure I was as even as I could be before logging major mileage on the bike or running. Like you, I’m pretty certain my initial problems started due to major knee injury (ACL and other clean up) that essentially ended my basketball “career†almost 25 years ago. To me, it’s worth being evaluated to ensure you don’t have any compensatory issues you’re making worse with repetitive movements. (n=1, of course)
EDIT: Imbalance was always 55/45 to 53/47. Didn’t seem major at the time.
That’s not a large imbalance. I wouldn’t worry at this time.
Hey folks,
I always see a 54%-46% or 47%-53% left/right power balance after each ride (a year’s worth of data).
I am thinking it might stem back to a football injury I suffered when I was 20 - an ACL injury which required a reconstruction.
Is this unusual?
If so, is the imbalance big enough to worry about…?
I’d ignore this–it’s not enough to be actionable, and year end stats on this metric really don’t mean a lot. Most–probably virtually all–riders will demonstrate some form of imbalance, and the imbalance will shift with effort and cadence. It’s kinda like the advice on pedaling circles. There’s some value in the common sense understanding of such items, but the actual utility of acting on them has minimal, if any, value.
Just out of curiosity does one shoe wear more for running around ball of foot? One of the reasons for left right power balance can be lifting your right leg more during leg left push down (so you get more instantaneous force out of your left down stroke) versus the left leg unilaterally applying more power (as an example). I woudl always seem to get 52/48 or 51/49 in favour of left, which really baffled me because my right side ball of foot on running shoes would always wear more. Then I inferred that maybe I am more coordinated on right side, and right leg unweighs the pedal a bit better for left leg to push down…on right push down, uncoordinated left leg was in the way (maybe, I don’t know, just a hypothesis). In XC skiing my dominant push off is right leg. But this was never reflected in biking power balance data. Also in soccer I have more control kicking with right leg with weight on left leg (similar to pushing down with left leg on pedals and unweighing right leg). So maybe there is some subconscious bias from other sports
Hey folks,
I always see a 54%-46% or 47%-53% left/right power balance after each ride (a year’s worth of data).
I am thinking it might stem back to a football injury I suffered when I was 20 - an ACL injury which required a reconstruction.
Is this unusual?
If so, is the imbalance big enough to worry about…?
I would think that if you had a physical issue it would be dominant one side.
Is it really random from ride to ride ?
(Also consider that some imbalances are due to slight imprecision in power meters on each side)
Hey folks,
I always see a 54%-46% or 47%-53% left/right power balance after each ride (a year’s worth of data).
I am thinking it might stem back to a football injury I suffered when I was 20 - an ACL injury which required a reconstruction.
Is this unusual?
If so, is the imbalance big enough to worry about…?
I would think that if you had a physical issue it would be dominant one side.
Is it really random from ride to ride ?
(Also consider that some imbalances are due to slight imprecision in power meters on each side)
Hi - it’s 53/47 or 54/46 on every ride I do. Shorter efforts e.g. 1min or so can be 50/50, but as the duration goes on, the imbalance appears.
Just out of curiosity does one shoe wear more for running around ball of foot? One of the reasons for left right power balance can be lifting your right leg more during leg left push down (so you get more instantaneous force out of your left down stroke) versus the left leg unilaterally applying more power (as an example). I woudl always seem to get 52/48 or 51/49 in favour of left, which really baffled me because my right side ball of foot on running shoes would always wear more. Then I inferred that maybe I am more coordinated on right side, and right leg unweighs the pedal a bit better for left leg to push down…on right push down, uncoordinated left leg was in the way (maybe, I don’t know, just a hypothesis). In XC skiing my dominant push off is right leg. But this was never reflected in biking power balance data. Also in soccer I have more control kicking with right leg with weight on left leg (similar to pushing down with left leg on pedals and unweighing right leg). So maybe there is some subconscious bias from other sports
Thanks for the reply, however I haven’t run for 2-3 years. I am ‘right handed/right footed’, but never noticed anything with my shoes.
After my ACL surgery, the graft stretched slightly, so the knee is a little unstable. That, plus me right quad never totally catching back up (size wise) to my left, is what I assumed was causing the imbalance.
I’ve had nagging knee issues the last year.
A few weeks ago I propped myself up on a wall like a wall sit and noticed my right thigh looked atrophied compared to my left, and sure enough, there was almost an inch difference in the size.
I pulled up my power balance and set it as a field on my Garmin and it was skewed around 54-46%, so since then I’ve been steadily working on having an equal balance. There was definitely some strength differences. Last week I finally did an hour with 50/50, and without concentrating on it I’ve been getting more consistent 51/49.
I think doing that plus some targeted strength work in the gym has definitely improved strength. I’m hoping that translates into improved knee function as well.
What sort of targeted strength work did you do?
I do one-legged knee extensions, one-legged leg press, one-legged squats (to a bench and back up), and one-legged drops (touch opposite heel to next step) on steps.
It’s not unusual. Don’t worry about it.
YMMV
Hugh
This ^^^
You mentioned:
it’s 53/47 or 54/46 on every ride I do. Shorter efforts e.g. 1min or so can be 50/50, but as the duration goes on, the imbalance appears.
I came here to say exactly that.
Your experience is very common. The left-right imbalance convergence, as you perform at progressively higher power outputs, is a good sign that you can safely ignore this and it’s just a weird quirk.
Humans are not symmetrical.
Trying to be symmetrical is an injury risk in and of itself.
I’ve had nagging knee issues the last year.
A few weeks ago I propped myself up on a wall like a wall sit and noticed my right thigh looked atrophied compared to my left, and sure enough, there was almost an inch difference in the size.
I pulled up my power balance and set it as a field on my Garmin and it was skewed around 54-46%, so since then I’ve been steadily working on having an equal balance. There was definitely some strength differences. Last week I finally did an hour with 50/50, and without concentrating on it I’ve been getting more consistent 51/49.
I think doing that plus some targeted strength work in the gym has definitely improved strength. I’m hoping that translates into improved knee function as well.
What sort of targeted strength work did you do?
You could do lots of different kinds of drills and best case you might not hurt yourself. The variances that you’re seeing are completely normal. I’d counsel that you ignore this metric as it’s meaningless and focus more on actual training. Just because something can be measured doesn’t mean that it’s important. Humans don’t tend to perform symmetrically in most activities.
You’ve recd several responses that are counter to my personal experience. For what its worth, when I rode/ride harder it always got much closer to 50/50.
Best of luck to you. I’d not rely on slowtwitch to tell you something is/isn’t worth addressing. I relied on it a few years back. Most likely it’s no big deal
You’ve recd several responses that are counter to my personal experience. For what its worth, when I rode/ride harder it always got much closer to 50/50.
Best of luck to you. I’d not rely on slowtwitch to tell you something is/isn’t worth addressing. I relied on it a few years back. Most likely it’s no big deal
What you describe in para one is pretty much the case for most riders. The ratios will vary depending on power, cadence, fatigue, etc. Mostly, it’s a self regulating process.
Interesting discussion here…
In my left knee, I have some “moderately complex” tearing in the meniscus, as well as a noticeable amount of osteoarthritis in my medial compartment (and likely some amount of OA in the right knee, too – though that one hasn’t been imaged).
Over time, I appear to have developed some unconscious “guarding” techniques to protect that left knee joint – which were noticeable when I finally did running gait and cycling pedaling video analysis. I’ve been working with my PT on a long-term plan to improve glute activation, quad engagement, ankle stability and range of motion, core engagement, etc – to improve my overall movement mechanics and lessen impact on my knees.
While on the bike, what appears to happen over time is that my left leg starts to slack off. Less power applied on the downstroke and more guarding on the recovery portion. If I’m not paying attention, my left side will start letting my right do more work on its behalf. Last year, I added Avg L/R Power Balance %s to the fields on my head unit. So now I get more real-time quantitative feedback to tell me when that slacking/drift starts to occur. When I see myself go to 49/51 or 48/52, I can then be more aware in monitoring my pedaling stroke on the left side, making sure I’m engaging throughout the stroke cycle, keeping my hips and femur moving smoothly, etc. In other words, that feedback loop is allowing me to ensure my left side continues to get an equivalent training load during my training rides. I also find that I’m able to sustain higher power output when I’m using the feedback to help actively keep my left side engaged on the pedals.
Over time, I’m finding that the rate of slacking/drift is slowing. That is, in general, it takes longer on my rides before I see my left leg start to fall into those old movement patterns. No sign so far of any injuries related to this. My take is that, because I get more immediate feedback when the balance ratio starts to drift, I’m able to intervene sooner, and with less impact. My goal in trying to keep at the 50/50 balance isn’t just for some theoretical benefit – it’s to work to improve the engagement of both sides of my “power systems” on the bike, to help get the most thorough benefit from my training time. Seems to be effective so far, without any downsides appearing.
During any type of racing, I ignore that metric – since I’m not focused on the same factors that I would be on my training rides. As always, YMMV…
Michael
Studies have shown 90% of people have a leg length discrepancy. Some of the best fitters account for it. My left leg is 1/4 inch shorter than my right leg. I had a hitch in my pedal stroke on the left side. Eventually my knee started killing me on that side and I had pain at the top of my right hip. My power balance was always weighted more to the crank side. Generally 51/49 or 52/48.
I put in 2mm worth of Shimano cleat spacers and it instantly leveled me out. The pain also went away. I’m not saying this is your issue but it might be worth exploring.
Hey folks,
I always see a 54%-46% or 47%-53% left/right power balance after each ride (a year’s worth of data).
What power meter(s) are you using to get this data?
Hey folks,
I always see a 54%-46% or 47%-53% left/right power balance after each ride (a year’s worth of data).
What power meter(s) are you using to get this data?
For me, Favero Assioma Duo
.