Left / Right Power in TR Performance Analytics?

I’d like to see a live or average of power balance. I work a ton on form and having this metric visible during sessions, especially hard efforts, is useful in understanding the impact of form breakdown and reminds to take action.

I’ve previously used on a computrainer and found it helpful in smoothing out pedaling.

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I can see where maybe being 50/50 is not a prize worth the fight, and may not be worth the development effort for TR.

But I wonder I’d maybe the kinds if pedaling biofeedback that come along with that devlopment tool may have other benefits. The data the lets you balance would help you avoid mashing, identify wiether you’re over or under scraping or kicking. Single leg drills might come easier. The tool may be too niche for just balance, but maybe other refinement opportunities could make it pencil out.

If you are 50/50 it is not an issue. Sure don’t worry.

If you are 54/46 (as I was/am at times) it is. The difference being 8/46, ( to bring it up to the equivalent left side) which is around 15% power lost in one side. Now that requires action.

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Agree. Need to address an imbalance like that.

Curious - did you notice you were imbalanced before you saw the power data?

No. And I was fine on the road bike with the pedals showing 50/50. It is the more extreme position on the TT bike. My Physio identified a hip flexor weakness. So I have some exercises to do, but it does recur. I have not fully nailed down the reason. I keep an eye on it, hence worth seeing for me.

I also would like that the metrics at least where recorded to the file when recording via trainerroad. Now i doubletrack with my Garmin. But, FWIW I Bought Assioma Duos instead of unos because I have got a previous hamstringinjury and a bit of a lopsided position so I was sure that my balance was quite off. It turns out my balance is almost 50-50. In intervals it might get a bit skewed, but never more than 2 % off.

One really useful thing I like about dual sided pedals is accuracy validation. I had a right assioma pedal that the power reading drifted on and I only noticed because i tracked L/R balance. I know i’m roughly a 50/50 split but with the faulty pedal I started 50/50 after a cal but ended the ride 60/40 (Favero were great supplying a replacement right pedal btw).

I’d love the data logged and sent to garmin connect etc - visible on trainerroad itself would be a bonus.

I have been about 45-55 ever since I started cycling. I mean, I didn’t have power 6-7 years ago, but the left leg would always give up before my right and a power meter just proved that. My left leg has been a little weaker in the gym etc, since my last left knee surgery in 2011. I’ve done the rehab including unilateral work. I don’t think it’ll ever change.

So what I am saying is, some people will always have an imbalance and any working on it is futile.

If you don’t think it will ever change, it will probably never change :wink:

I’ve had 3 surgeries on my right knee (2 meniscus repairs and an ACLR) for the most part in day to day life my legs are equal.

However, when riding, especially on focused intervals, I sense some power imbalance and fatigue tolerance between my 2 legs.

Currently I’m using a stages left only PM, so it’s hard to validate things. I’ve just pulled the trigger on a pair of Assioma Duos.

Once they are up and running and providing data, if I do have a significant imbalance, I would definitely try to address it with a view to becoming more efficient and ultimately stronger

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That might be true for you, @DaveQB but I am can get mine back to 50/50 and I am 50/50 on the road bike. The imbalance only occurs on the TT bike at particular positions - positions I want to train myself to be in over time. So, saying

is not any argument against those of us who have an imbalance that occurs in situations, needs monitoring and can be changed.

Well actually…I had my first right knee surgery in 1997. I have a 6 surgeries on my right knee. My left leg/knee was my strongest up until my first left knee surgery in 2011 and then suddenly my right knee was my strongest even though it had way more surgeries. Or as I like to put it, my weak knee became my less weak knee and my strong knee became my weak knee :slight_smile:
Something in my 2011 surgery has really set my left leg’s strength back and even though my right knee is a mess (out of meniscus and bone cartilage and heading for a knee replacement) it is the strong of the pair :confused:

That hopefully better explains the reason for my conclusion that my left leg won’t ever equal my right. In fact I get muscle strains and nerve impingements in my left leg and glute that I regularly have massaged out. I put this down to my left side trying to keep up with my right but can’t. Maybe I am that special snow flake :slight_smile:

The price we pay for years of football.

With all that said, I am still looking for answers with my mate, who is also my physio, and my massage therapist.
That turned into a long reply :astonished:

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Yup, football played a major part in my knee saga too. Never go near the damn sport nowadays. Dreading the day my toddler grows up and asks for Dad to go kickabout with him :joy:

My repaired knee was and still is my dominant knee, but my left feels stronger. I recall the physio at the time saying that this is usually the case because the uninjured leg wants to protect the injured leg and thus it gets stronger.

Maybe we’ll never get perfect balance, maybe we’ll never need perfect balance, but we can probably make it better than it is. We’ve all got a bit of drive and motivation in this forum, otherwise we wouldn’t be here :blush:

Right. That makes sense. Just saying, there’s many circumstances.
I’d certainly work on the imbalance in your scenario. Good luck!


I had a Rt knee replacement in 2015 & have been using a Stages left only power meter since the knee replacement. I’ve always wondered how my power compared between the L R legs. This year I have a new bike & went with a Quarq Power meter. I’m consistently showing around 16 % less power on my Left side (the leg without the new knee). It would be nice & useful for me to be able to see & track the difference in my legs power over time using TrainerRoad sessions.
My bike with the Stages left only power meter is the bike I use for indoors. I use a Tacx Neo trainer so I’m switching to using the power meter on the Neo only for indoor training. My thought is that this will give a more accurate gauge of my power output & closer to what my Quarq will be showing for my outdoor riding.

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It would be helpful if L R power is not going to be displayed in TR, would it be possible to send that information on to Garmin Connect where we could see it there? I notice it is not in the information that is passed on to Garmin Connect.

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I am puzzled @jerock. Is that because the Quarq power meter stores its LR data in a different way to the V3 and Garmin connect? Have you checked with Quarq and Garmin on this?

You’re using a second device to record the L/R data, it appears that he is not. The way I read it he wants to record on one device but have TR pass L/R data through.

As far as I know, neither power meter stores any data. They essentially just have the ability to measure data and transmit it to a recording device.

That’s probably correct. When I ride outside with the Garmin Edge I have the L R data transferred to Garmin Connect. When using TR without the Garmin Edge collecting that data it’s not transferred to Garmin Connect. So the TR app is not collecting the data I assume.
Not sure how much it’d take to if TR is not using that data to at least pass it through to Garmin Connect.

Interesting article…

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Not read the article in full yet, but there is a fundamental problem with using strain gauges on non-symmetrical cross sections to determine bending strains as it’s impossible to isolate them from strains which are due to axial forces or bending forces in the transverse direction. Typically these are cancelled out using a Wheatstone bridge arrangement around the centroid of a symmetrical section so that only strains which are caused by forces propelling the bike forward are measured.

There is also a problem with machining tolerances which are typically not good enough with a CNC machine that can lead to even greater inaccuracies due to differing thicknesses across a section that you would otherwise assume to be uniform in thickness.

In my opinion the power meter manufacturers are taking us all for a ride. I have two Stages Cannondale Si cranks (which should be good ask they are symmetrical) but they don’t give comparable output to either my Assioma pedals or my trainer.


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