A power meter, without structured training? Musings after a couple of years.
 

First off, unless you do structured training, I do not think that anybody actually needs a power meter. I have had a PM for a couple of years, without aspirations for structured training – it’s a nice accessory for somebody who likes numbers, but definitely non-essential.

So here’s a report after about two years of using Favero Assioma Duos.

Like probably many, I got interested in having an outdoor power meter because of indoor training (=Zwift), where power is everything. After focusing so much on power, I began to wonder how my indoor and outdoor performances might compare.

Answer: They mostly don’t. Unless you are doing intervals, FTP tests, or specific events like time trials- the numbers you get outside are going to be quite different from your indoor efforts. My best 20 minute power efforts are all indoors, because outside I don’t really have the opportunity for 20 minutes of steady hard effort. Maybe it would be different if I lived in a place with long climbs.

But that doesn’t mean that I haven’t learned things from my PM and that I don’t like having it. I have and I am glad to have it. Mostly, I just like having the numbers. I like knowing that I sustained X watts on a particular hill or on a long pull at the front. My sprint has always sucked and my pitiful 5 second power numbers prove it, but I like seeing instances when I get to the higher end of my range.

Some things that I’ve learned:

*Putting down power on climbs is automatic, but keeping the power going as you crest the climb takes some practice. Of course, you shouldn’t stop working just at the top of a climb. You have to keep working until you get back up to speed, whether the climb ends with a descent, a flat, or a false flat. I thought I did this pretty well, but I didn’t. Going up a climb at whatever power – 275 W or 400 W – I realized that as soon as the resistance on the pedals dropped, my power dropped A LOT. If you had asked me, I would have guessed that I was going down to something modest – say 180 or 220 W – because after all, I was speeding up. But actually power was dropping to 80 or 120 W. And this was true for hills that weren’t that hard and for which fatigue wasn’t much of an issue. I just wasn’t quick enough to change gearing and effort. I'm still learning to do better at these times, but it takes conscious effort.

*yeah it's helpful to know your power output to keep from blowing up. I'm not doing the Chris Froome, staring at my PM all day, but if I'm in a situation when I'm putting out some effort, it's good to check the power numbers and see if I'm at a level that I know I can sustain for the task (climbing that hill, doing that pull, trying to bridge up during the sprints that my cycling group does, etc.). Mostly I can do this by "feel", without the PM, but we've all misjudged ourselves at times, based mostly on enthusiasm, and blown up after an effort that was too hard. I do that less now with some numbers in front of me.

*I thought L/R power was useless until there were injuries and I changed my bike fit. I have the Assioma Duo pedals because I was dumb and suspected (wrongly) that my power might be very asymmetric. For a long time, it seemed that two-sided had been a waste. My power balance was almost always 50/50 or 51/49 or, very seldom 52/48, with no preference for which leg had the higher value. One sided would have been just fine. But I’ve been fighting various injuries (in both legs) and partly because of that, I recently changed my bike fit, including my cleat positions. Since then, my power balance has been a steady 53/47, always with L>R. And this is even though it’s my left leg that has the more serious injury. Not that this has a big effect on my total power, but something is going on. What is it? My current hypothesis is that my legs haven’t got used to the new cleat positions, which changed more on the right than the left (because the right knee wasn’t staying straight through its revolution). I think I’m still spinning as I did before with the left, but that the right is doing more mashing, without smooth effort through the revolution. I can work on this, but I wouldn’t have noticed it without the odd L/R readings.

Conclusion: Most of us do not need a PM, but I’m glad I have one.

Yeah, this was a topic of discussion the other day - between the terrain and the traffic controls in the Twin Cities metro, there's very little opportunity for setting a decent 20 minute power figure. The other day, I managed to average just under my FTP for 20 minutes, but I can certainly do better than that on the trainer.

For that matter, even setting a 3 min figure is tough around here. A website that I use for tracking my workload (intervals.icu) will look at efforts 3 minutes and longer for estimating FTP... so I naturally want to find a 3+ minute hill to hammer on :lol: Still haven't found one within 30 miles, though.

Thank you, MinnMan . This post was very informative to me. I've been considering getting a power meter. In fact, the Assioma pedals are on my short list. I just have to save a little more money for them. There was a recent thread where someone asked about affordable options to move between two bikes, and it yielded a lot of good discussion. Here as well, you answered some of my specific questions and also helped me think through some more general aspects of the topic. Good stuff!

Until I got a massive blower, my outdoor FTP and PD curve was always better outside.

If training isn't structured, how do you know if you are improving? PM is just a tool. After some use, you intuitively know your power and are very unlikely to blow up on a climb. I play a game on training rides. I try to guess my power w/o looking. Rarely am I off by more than watts.

I've been using a power meter for about or close to ten years. In all that time I've found exactly one stretch of road I can get a decent 20 MMP test in without having to drive my bike somewhere, and even then traffic can break everything. :(

Guess I am lucky, I have one 10 minutes from me.

Very useful post! Saved me a minimum of $300!

Yeah that's way too long to ride, we're talking about bikes here. ;)

Yeah, Ohio and High Bridge/Smith have intersections that break up your effort. I think that the coulee south out of Afton should be good for 3 minutes. Definitely no intersections and though it's got a false flat, it's a pretty steady climb. The KOM is 3:02, but to approach that you'd have to be a cat1 or cat 2. https://www.strava.com/segments/1912611

I appreciate this post. I recently, last month got the same pedals. The most important lesson for me as you said to keep the power "engaged" on hills and flats. There have been many times I thought Im doing great and working hard, but once I look at the power numbers its easy to see that the opposite was true. Im still glad I go my pm pedals.

Yup, that segment in Afton is the closest one that I can think of, but that means an ~80 round trip for me, which also isn't conducive to a hard 3 min effort.

it’s a useful tool training to climb where you don’t have hills. As noted, climbing intrinsically requires you to put out a high level of power. It’s harder to keep that level up on flats. A power meter allows you to train on the flats maintaining the power needed to climb, where you might tend to slack without the reinforcement of the power meter. However,

Good post.

I'm sort of a numbers guy too but I'm not doing structured training at the moment. I am interested in getting the Garmin XC200's for my bike though and I do have aspirations (if my body holds up) to get into a structured training system, maybe even hire a coach.

But even if I never do that I find it interesting to compare rides on the same route but at different time periods to see how things differ (and are hopefully moving in the right direction) and a power meter would be a super cool toy if nothing else.

Here in the Bay Area we definitely have plenty of hills, but we also have some decent stretches of road (Canada, Bay Trail) where you can settle in for pretty long stretches.

I have pretty much the same conclusions as you draw, except I feel I do need my power meter. It really does help me ride better, in the ways you point out and more. Anything that makes a significant dent in my ability to ride better is something I need.

That said, I don't require it. I'd screw up not knowing my power and overdo/underdo something. But I would still have a great ride.

Maybe in a couple years I will have enough sense that I won't need the meter, but I find that in certain conditions I can still be pretty far off in my guesses of how much power I am burning. Topping out on a hill I am usually at less power than I think I am, and on really hot days I can sometimes be doing 1.5x my FTP and feeling like I'm at my FTP.

A lot of people do unstructured training with power. That's good too.

Power meters were more expensive when I bought my Vectors. I bought dual because $700 was more than I was willing to pay to not have the right number. It was the principal of it. 🙂

And then I injured a tendon in each foot. It runs through the ankle too. Like you, one worse than the other. I can see how it's doing from the L/R numbers. I don't know if your pedals measure platform center offset, with the nature of my injury that's been very useful too. When I start to aggravate it, it affects how I ride the bike.

I'm very glad I have this data. I wouldn't recommend somebody to buy them for this reason who wasn't already injured, but if it happens, this and the years of preinjury data are bona fide useful.

I haven't done any structured training since the pandemic started, unless strict recovery or endurance efforts count. I decided that I'd lose motivation to flog myself with intervals when I had no tangible goal with events and group rides cancelled. However I still used power continuously to keep track of my time in zones, training stress, to pace, and compare to past efforts.

L/R balance is also useful to me as I've changed shoes, cleat position, saddle height and setback, and crank lengths, all which shift my power balance one way or the other in ways I wouldn't have been able to tell otherwise.

I find power meters very useful both indoors and outdoors. But I find it a lot easier to average a higher wattage indoors simply because there is little to no coasting involved on the trainer. All my local outdoor rides consist of undulating rolling hills with very little consistent flat riding. So while I can get my indoor Variability Index (VI) very close to 1, outdoors my VI is more like 1.3 or even higher. So one thing I try to work on outdoors is applying more power on the slight downhill sections where it is so tempting to soft pedal, especially with a tailwind. A power meter helps me to see when I'm slacking! Power also helps me to pace climbs on long events. I spend the first hour trying not to over-reach my target power and the last hour desperately trying to maintain it! So works both ways, lol.

Ugh. I disagree with most of what you've written except for the conclusion: I agree that most riders don't need a PM, and I'm glad I have one.

Structured training was originally developed as a way to train before there were power meters. A coach couldn't see how much you were training other than hours and distance, so structured training was a specific prescription and plan to work on certain fitness goals in the absence of direct information about how hard you were working. We often talk about "dose" and "response." In athletic performance, we could sometimes measure response but we didn't used to have very good ways to measure dose, so structured training was an attempt to regulate dose. Running and swimming don't have well-developed power meters so training prescriptions in those activities tend to be fairly structured. In that sense, a power meter enables *less* structured training (it also, of course, enables hyper-structured training). In essence, a power meter expands the range of training so that you can do unstructured, structured, and hyper-structured training and fit all of it into a larger training scheme.

Second, L/R data, even when recovering from an injury, isn't as straightforward to use as you suggest -- witness your own recovery from your left leg injury. You now have a puzzle about why your L produces "more" power than your R even though your injury was to the L side. In my own case, I injured my right side but I had data for years prior to the injury of total power. I could see total power drop, so I just worked to regain my total power. If I'm producing more power what do I really care whether I'm more asymmetric or more balanced? All that matters for the bike moving down the road is total power, so that's what I focus on.

So, once again, I agree with your conclusion but not for the reasons you've given.

Definitely two different worlds inside and out. Power is invaluable inside. Since I ride on ancient Performance rollers ( with resistance fans ) I don’t have the smart trainer feedback. Structured workouts ala Sufferfest have really been a valuable addition to my routine. Outdoors it requires a level of attention I am not willing to give to utilize power for structure. Too many other distractions and concerns to focus on power. At a glance, however, they can be a good metric, but I don’t want to spend too much time looking at my Bolt. I suppose I might be able to set target power goals with a audible reminder when I am out of them..,
All in all they have been a great investment.

I would save yourself a few bucks and get the single side. That’s what I have and it’s honestly all you need unless your focused on structured training that involves knowing the power from both legs.

Yeah I’m not sold on double-sided power either. At least not for general use. I get total power on my trainer (which actually gives an estimate of L/R balance too) and have a single-sided crank power meter on my road bike. From what I can see from the trainer my L/R balance is always within 1% on average and the total power reported from my single-sided meter is always consistent with my trainer. So I don’t see how a double-sided power meter would be of any use to me.

One of the best uses of a power meter is to improve positioning on the bike to lower aerodynamic drag.

I also tend to use the PM as a governor to keep power below a certain level on certain type of rides. I had a coach for a while and he would prescribe a Zone 2 Endurance ride of a certain number of hours and range of power. I would routinely exceed the upper power range due to hills, he told me to stop riding those roads.......but, "Coach, all the roads are hilly here"......then, walk them or drive to a flatter area or use the trainer.

You do not need 20 minute tests to get your FTP. Once you have enough rides, various online programs can model your power duration curve. It is a lot easier than taking one's own lactate while on a trainer.

Coming from you, I'll take that as a win. As to most of my post, about what I learned: You can tell me that I should have learned it differently, or that I should have drawn other conclusions. But I didn't. It's my report. I think your contrary points may be helpful to others, though.

This is the main reason I have not gotten a PM. While I am a data geek, I just don't have the surroundings to get good figures so I will just stick to the trainer to get power data.