Power Meter Metics: Smoothness / Effectiveness / Pedal Phase / PCO

Quick check-in to ask if anyone uses these metrics in the title on a regular basis? Pedal Smoothness and Torque Effectiveness are supported by most(?) power meters these days. Cycling Dynamics has been limited to Garmin Vectors to date so hasn’t been given much attention.

imo, Pedal Centre Offset (PCO) looks to be the most interesting. Real-time feedback if you’re getting sloppy when putting power to the pedal.

I suspect these kind of metrics would be more valuable for long sustained events like tri/im? I’ve never used them in road racing / crits / TTs.

Assuming they have any value at all. So many metrics being measured, but no significant research to show what actionable intelligence they provide.

I do look at torque effectiveness and pedal smoothness fairly regularly, but find it hard to draw any real information from them.

I think this is for a combination of two reasons…

  1. If the duration is too short, then numbers aren’t generally really reliable.

  2. Smoothness & Effectiveness varies with my power output (particularly for effectiveness). At say, 200W, my effectiveness is typically between 50-80% and my smoothness is 15-25%. But at higher power numbers, say 500W, my effectiveness is typically between 80-95% and my smoothness is 25-35%. Above 1200W, my effectiveness is almost always 100%, but smoothness seems to level out to just over 30% from 800W onward.

I don’t do a lot of steady state riding outdoors (Kickr only indoors for training, Shimano PM on my race bike which is used 90% for doing crits), so I don’t tend to have much in the way of comparable blocks to compare and contrast throughout a ride.

I do see that the more steady state my effort, I get a tighter band of variablility to effectiveness (i.e. trying to do a 20min effort vs. a crit results in less variability to my effectiveness for a given torque). Again though, this is probably more about locking into a specific power/cadence where i’m relatively efficient…

What do I do with this information? errmmmm… basically just look at it, cause I like looking at data. The only thing I have done is to work on my pedal stroke to try and improve smoothness at lower power levels (for the same cadence).

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imo, Pedal Smoothness isn’t a good metic, and isn’t exactly what we’d call ‘pedalling smooth on a bike’. PS being “how much like a dynamometer are you”… to which the answer is not at all, and trying to be one and hit 100% isn’t the right thing to do. I have a head unit here that rewards me with ‘Good’ and ‘Excellent’ the closer I get to 100% PS and it’s sending me insane. /rant. :slight_smile:

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I know that this is correct, yet I still have this burning thought that improving my smoothness will reduce my ‘rocking’ at high cadence / low power… even if it is contradictory to what i’ve read :crazy_face:

In reality, I probably need to be working on my core strength as a starting point… :thinking:

Maybe you can channel your annoyance from the ‘positive reinforcement’ into free watts? :rofl:

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Anybody out there have any knowledge on how to interpret cycling dynamics data? Specifically Power phase?

I’ve been running Assioma Duos for around 3 months now. In the beginning, I observed some LR imbalance, usually in the order of 55/45 or 56/44 range.

Whilst it wasn’t a huge issue, I decided to try and improve it. Now, having addressed some cleat issues (position and spacer), some stretching and with a bit of added awareness and focus, I can usually see 53/47 or even 52/48. Marginal gains and all that :nerd_face:

Now, I’m looking at the power phase data and notice my legs are generating power on a slightly different phase of the pedal stroke.

With a bit of help from Google, in trying to interpret my data, it seems my power phase is starting a touch early on both sides. More so on the right, where it also appears to be ending earlier than it ought to be?

Anybody else been looking at and/or acting on the data they get?

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I think this is a classic example of too much data. Basically if it int brok don’t fix it (as we say in UK). Everyone has a left right imbalance and if it’s not causing you problems don’t waste your efforts when you could be concentrating on more productive areas. That’s my thoughts anyway…

I’m not convinced on that one. To start with, there’s an underlying assumption that when placing an asymmetric object (a human foot inside a cycling shoe) on a partly-symmetrical object (a pedal body), there’s an optimal force vector positioning at the center of the pedal, and an underlying corollary that efficiency somehow would drop as you diverge from the centerline. I see no biomechanical or pure mechanical reason for that to be the case, nor have I ever seen any data supporting these assumptions. Why the optimal alignment of hips, legs and feet should coincide with the centerline of a pedal (regardless of the Q-factor, what’s more) is beyond me.

This said, @GPLama refers not to the actual positioning of the force vector, but to its change with fatigue. That’s another question - related for sure, but different. Is there any data out there that supports a drift of the pedaling force application point (a.k.a. pedal center offset, PCO) with fatigue and a link to reduced pedaling efficiency?

To me, this is another topic that individuals too commonly extrapolate their experiences out to larger groups, i.e. this is isn’t helpful for me or I don’t understand it’s utility, therefore it isn’t useful.

I have been looking at it strictly retrospectively after a training ride is finished, and knowing that I am going to be looking at it later has been very helpful in the moment for focusing on pedal smoothness/torque effectiveness and the stuff that is generally addressed with pedal drills - what gets measured gets managed. In my opinion, and it is true for me but maybe not everyone, it helps endurance and overall power to be developing muscles throughout the pedal stroke as would be true for a pedal stroke with high % torque effectiveness. Over time, it has led me to be much more comfortable at various positions and cadences at a given power.