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leg power asymmetry

Old 04-25-22, 12:54 PM
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mschwett 
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leg power asymmetry

so i finally have gotten my dual sided power meter working on both sides - I THINK - and as i suspected my right leg is doing a lot more work than my left leg!

not sure if it's because i'm right-side dominant, or due to injuries over the years (many stress fractures while running) but over the course of a 4 hour ride, i'm at 44/56, which means the right leg is doing 27% more work. not insignificant!

my output is generally cardiac limited, but for short bursts it would obviously be great to get that left leg strength up. any suggestions other than just trying to be more mindful of it? for example, when i get out of the saddle or start from a stop i always make the power stroke with the right leg first, which i'm trying to stop doing. exercises or stretches off the bike?
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Old 04-25-22, 04:33 PM
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There's been a lot of discussion about this here over the years. One perspective is that it doesn't really matter, you get your power from wherever you are able. OTOH, it's possible that it's a symptom of poor technique which you could possible improve, and it's also possibly indicating some old or present injury.

A few notes though:

1. I too see asymmetry (more about it below), but I wouldn't evaluate its extent from just a few data points. I see quite a few fluctuations from ride to ride. Take the average over 20 rides or so.

2. As I've posted earlier, I didn't used to have an asymmetry, but now I do owing to an injury. It's typically in the range of (55-57)/(45-43). In the last few weeks, It's been coming down to (52-53)/(48-47). I take this as a measure of my injury recovery.

3. Over a 4 hour ride, this may not matter much, but which leg do you use to unclip? You might put out a lot more power on the other leg each time you accelerate from zero. Again, doubtful that this has much influence on longer rides.

4. If it really is a matter of technique or stretching/exercise, probably seeing a good bike fitter/PT would be worthwhile.
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Old 04-25-22, 06:55 PM
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One-legged pedaling on a trainer. That works. I can suggest methodology if you are interested.
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Old 04-26-22, 01:53 AM
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I can only say that if some exercises cause severe pain, then the exercises should be stopped or replaced.
I am not a doctor or a trainer, they can advise here
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Old 04-26-22, 09:38 AM
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Sure you can probably balance your power. But even if you got both legs balanced to put out the same amount of power in the same places during the pedal stroke, the bike is still moving in surges of power. And concentrating on strengthening one leg is just failing to also increase the power in the other leg, so you wind up with a balanced but less powerful engine.

I suppose if your legs are way way out of whack it makes sense to strengthen one to a reasonable semblance of the other.
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Old 04-26-22, 10:04 AM
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appreciate the input, all! my guess is that i’m in the “it doesn’t really matter” camp since my heart rate sits in the preferred zone (for me 100-130 max) and stays there for most of the ride. if my left leg was doing more work, my right would just do less, no?

… or do stronger muscles use less oxygen to do the same work?

i don’t have any significant pain/discomfort when riding, other than the good kind
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Old 04-27-22, 07:21 AM
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I tend to favor my left (i.e. make more power) because my right knee is pretty wracked up from injuries, surgeries, and arthritis. However, being conscious of that tendency, I can completely correct it by being more tolerant of (or maybe ignoring) the pain and discomfort in my right and deliberately pushing harder despite it. So, for example, I can see L/R 46/54 on one ride, and then the exact opposite, 54/46, on the next. It’s also not unusual for me to see 52/48.

I’m not sure how power production figures in all that because there are so many variables ride-to-ride, bit I guess what it suggests to me is that the OP might want to see how simply being aware of the variation affects the situation before undertaking any leg-specific training to correct it.
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Old 04-27-22, 07:36 AM
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I just got a two sider PM and my L/R tended to be 47/53. I wondered why? I did bust up my left hip in September. I also noticed that anytime I start or get out of the saddle, the impulsive first stroke was with the right. I experimented with using the left to start up and when getting out of the saddle and got more balanced numbers but not perfect. I also get a weird cramp on the left leg muscle (hamstring muscles semitendinosus?) that is more inside and goes up to the butt. My new leather saddle also has a much bigger dimple where the left butt cheek hits the leather. I never had leg pain or that weird leather saddle dimple prior to the fracture of my left greater trochanter. And, have no idea what to do?? I can ride zone 1/2 no problem but at Tempo or higher, the muscle hurts. Maybe this is why my pedal balance sucks.
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Old 04-27-22, 02:38 PM
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Originally Posted by GhostRider62 View Post
I just got a two sider PM and my L/R tended to be 47/53. I wondered why? I did bust up my left hip in September. I also noticed that anytime I start or get out of the saddle, the impulsive first stroke was with the right. I experimented with using the left to start up and when getting out of the saddle and got more balanced numbers but not perfect. I also get a weird cramp on the left leg muscle (hamstring muscles semitendinosus?) that is more inside and goes up to the butt. My new leather saddle also has a much bigger dimple where the left butt cheek hits the leather. I never had leg pain or that weird leather saddle dimple prior to the fracture of my left greater trochanter. And, have no idea what to do?? I can ride zone 1/2 no problem but at Tempo or higher, the muscle hurts. Maybe this is why my pedal balance sucks.
Could be hamstring tendinopathy or it could be other things. You might try foam rolling before and after riding. Also, look up various eccentric stretching exercises, illustrated on youtube (i.e., search "hamstring tendinopathy eccentric stretches"). I have occasional battles with this. My main problem (I think?) seems to be bursitis of the ischial tuberosity (Near where the hamstring attaches) and that's a tougher nut to crack. I hope you don't have that one.
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Old 04-27-22, 03:46 PM
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I have Garmin power pedals and noticed that my left leg had a lower contribution than it used to have - post ride analysis.

I put left/right balance on my Garmin 830 screen and kept an eye on the L/R balance. I was right leg dominant but it was really easy to correct to 50/50. I practiced remembering what the 50/50 felt like. Fixed. My ratio is back to 50/50.

Do I think unbalanced power production matters? Yes, but I am not sure when and where. I think it affects my back if I overuse my right leg. And it seems like there has to be more muscle fatigue in my right leg versus left leg and it seems really bad to have unequal neurology.

However, since we a oxygen limited most of the time, muscle strength and equal force in both legs may not matter in most cases. I decided to fix mine. YMMV.

As a side note, I play classical piano and take lessons. My teacher is always on my case about my left hand being this or that not great. She is correct and it is always fixable with practice.
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Old 04-27-22, 04:00 PM
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Originally Posted by MinnMan View Post
Could be hamstring tendinopathy or it could be other things. You might try foam rolling before and after riding. Also, look up various eccentric stretching exercises, illustrated on youtube (i.e., search "hamstring tendinopathy eccentric stretches"). I have occasional battles with this. My main problem (I think?) seems to be bursitis of the ischial tuberosity (Near where the hamstring attaches) and that's a tougher nut to crack. I hope you don't have that one.
Thank you very much. I will try that.

I have noticed that if I bend over, the left muscle is really tight just under the hip whereas the right is supple. Maybe the foam will help

I hope to solve it. It has to be related to my accident where I broke a bunch of bones and they missed the greater trochanter despite me complaining endlessly in the ER about it. 4 Weeks post surgery, I got a Doc to look at the CT and he said, "Oh, you fractured your greater trochanter, nothing to do now". They also missed the broken scapula but that is another story.

I was thinking of trying to find a good fitter but this sounds like my problem to deal with.
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Old 04-27-22, 07:52 PM
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btw, I have foam rollers but for some muscles, including the upper portions of the hamstrings.I find that getting the pressure to just the right spot is easiest with gentle application of a wooden kitchen rolling pin
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Old 04-27-22, 08:43 PM
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Originally Posted by Hermes View Post


Do I think unbalanced power production matters? Yes, but I am not sure when and where. I think it affects my back if I overuse my right leg...
i’m now wondering if the mild numbness i get in my left hand, and only my left hand, is somehow related to
this asymmetry! when i rarely get back pain riding, it’s in my lower right back. so everything is asymmetrical!
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Old 04-27-22, 09:38 PM
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My L/R balance changes depending on saddle height. I have a leg length difference and found L/R imbalance to show up before my left knee starts hurting if I set the saddle too high or low.
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Old 04-28-22, 04:31 AM
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Originally Posted by mschwett View Post
i'm at 44/56, which means the right leg is doing 27% more work.
How did you get to 27%?
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Old 04-28-22, 05:07 AM
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if you are riding at 100 watts and the right leg is making 56 watts and the left leg is making 44 watts, the ratio of R/L = 1.27
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Old 04-28-22, 07:29 AM
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Originally Posted by PeteHski View Post
How did you get to 27%?
56/44 = 1.27?

or, 56-44 = 12, 12/44 = .27?

the numbers seem “sorta close to 50” but the difference between 44% of something and 56% is pretty big!
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Old 04-28-22, 07:36 AM
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Originally Posted by mschwett View Post
56/44 = 1.27?

or, 56-44 = 12, 12/44 = .27?

the numbers seem “sorta close to 50” but the difference between 44% of something and 56% is pretty big!
yes
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Old 04-29-22, 05:26 PM
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Originally Posted by mschwett View Post
56/44 = 1.27?

or, 56-44 = 12, 12/44 = .27?

the numbers seem “sorta close to 50” but the difference between 44% of something and 56% is pretty big!
Ah okay I see now thanks. I wasn't seeing past the 12% difference in balance. It was a late night!
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Old 04-29-22, 07:12 PM
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4 more hard-ish rides and my balance is holding at 45/55. i can definitely “target” the left leg and bring the power up to 50/50 by being very conscious of it, but after 10-15 seconds i go back to just enjoying the ride/effort and it reverts to 45/55.

i’ll have to try and work some exercises or one legged training in. but i only ride outside so that’ll be a bit of an effort!
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Old 04-29-22, 08:45 PM
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Originally Posted by mschwett View Post
4 more hard-ish rides and my balance is holding at 45/55. i can definitely “target” the left leg and bring the power up to 50/50 by being very conscious of it, but after 10-15 seconds i go back to just enjoying the ride/effort and it reverts to 45/55.

i’ll have to try and work some exercises or one legged training in. but i only ride outside so that’ll be a bit of an effort!
One-legged pedaling outside isn't so bad. Done it many times. You have to have a way to prop the lazy foot in the frame triangle, convenient bottle cage, something relatively secure. It has to be done on a gently climbing gradient, like 2%. It's a lot easier to do at a slower cadence, like 60-70.. The object of the game, just like in any strength training, is to do it until failure. In this case, failure is defined as having a slack chain at any point in the pedal circle. Two minutes until failure is about right, so pick a gear with that in mind. But don't let that 2' intimidate you. Being only able to do it for 1' is pretty common.
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Old 04-29-22, 09:04 PM
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Originally Posted by Carbonfiberboy View Post
One-legged pedaling outside isn't so bad. Done it many times. You have to have a way to prop the lazy foot in the frame triangle, convenient bottle cage, something relatively secure. It has to be done on a gently climbing gradient, like 2%. It's a lot easier to do at a slower cadence, like 60-70.. The object of the game, just like in any strength training, is to do it until failure. In this case, failure is defined as having a slack chain at any point in the pedal circle. Two minutes until failure is about right, so pick a gear with that in mind. But don't let that 2' intimidate you. Being only able to do it for 1' is pretty common.
nice. i am absolutely going to do that. thanks!!
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Old 04-30-22, 07:58 AM
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Originally Posted by mschwett View Post
4 more hard-ish rides and my balance is holding at 45/55. i can definitely “target” the left leg and bring the power up to 50/50 by being very conscious of it, but after 10-15 seconds i go back to just enjoying the ride/effort and it reverts to 45/55.

i’ll have to try and work some exercises or one legged training in. but i only ride outside so that’ll be a bit of an effort!
My question…Does your left leg get tired when targeted? I find that holding 50/50 is all mental focus. IMO, it is the neurology of firing more left leg fibers and relaxing right leg fibers that becomes automatic that will solve the problem.

I give one leg pedaling drills a meh. I have done them on the trainer and outside and but one more drill to master that does not seem to make a difference but I see no downside (careful not to pull a muscle). Maybe there is upside.
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Old 04-30-22, 09:23 AM
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Originally Posted by Hermes View Post
My question…Does your left leg get tired when targeted? I find that holding 50/50 is all mental focus. IMO, it is the neurology of firing more left leg fibers and relaxing right leg fibers that becomes automatic that will solve the problem.

I give one leg pedaling drills a meh. I have done them on the trainer and outside and but one more drill to master that does not seem to make a difference but I see no downside (careful not to pull a muscle). Maybe there is upside.
i get bored/inattentive and drift back to 56/44 before my left leg fatigues. it does feel unnatural, and if i get out of the saddle and really hammer, the peak power is notably lower (900 vs 1100) if i try and “focus” on the left side. so i think that would be the real advantage given cardio limits - more powerful sprints?

i actually first noticed this because of peaks, on the meter which was only reading from the left side i couldn’t get >900 peak watts no matter what i did.
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Old 05-01-22, 07:04 AM
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Just speaking for myself, but the ratio gets a lot closer or near on 50/50 the closer to and above threshold I get. The lower/easier power levels is where the difference exists.

In terms of training hours, unless your leg imbalance work is EXTRA to your training with the same hours otherwise.......you're actually giving up power if you focus on this more than a minor way. As half the KJ's spent for that time is a lot less than having one leg make a little less than the other. Food for thought.

Also, I'm willing to bet most folks could get it to within margin of error of the measuring device through precise bike fit updates to the saddle height, making sure your sit square on the saddle left to right, and any cleat position spindle length crank length fit coordinates perfected. And very gross imbalances are likely to be anatomical, leg length difference based issues needing cleat shims or something.
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