Training with a power meter
 

I've just ordered a 4iiii power meter from Merlin in hopes of streamlining/focusing any structured training during this lockdown period. Prior to this, I was out most days (commuting and leisure), and I would basically just ride. Nothing too structured or focused, other than increasingly longer rides targeted at my big ride of the year. With the lockdown, and all of my targeted rides cancelled or postponed, and long rides outside not the best of ideas at the minute, I signed up to Zwift and enrolled on their Build me Up 12 week training plan to keep me going and hopefully make me a stronger ride. I'm now in the second week of the plan, and decided to buy a power meter to help with it. My current set-up is a classic trainer with speed/cadence sensors and a HRM. When the power meter arrives, should I re-do the FTP test on Zwift?
Anything else I need to keep in mind while using it?
Thanks

There's a huge learning curve involved in training with power. Don't tackle it all at once.

Don't take another FTP test, that's very stressful on your body, and any good training plan applies stresses in measured doses. You'll be too fatigued to do the next workout properly. Trust the plan for now.

Yeah, but what's he supposed to use for power zones? Those plans usually call everything out as % of FTP. He's probably been using HR zones, so that could be a starter. When one uses HR for setting interval effort levels, one always goes too hard to start with and then gradually levels down to sustainable or more probably a little below because of the harder earlier effort. So a good approach is to take a wild guess at FTP. So if the interval calls for 95% FTP (SS interval), try to ride at a steady power will will give you 95% of your LTHR at the end, and that'll be ~95% FTP. An all-out 1' interval might be 180% FTP, so if one is doing a 1' interval, go as hard as you can, see your average power, and calculate from that, ignoring HR.

One could also simply substitute the CTS FTP test for any Z4 interval workout: https://trainright.com/cts-field-tes...-calculations/

If he's going to do this training plan by power, there's his learning curve right there. That's what I did, started using power right in the middle of a year-long training plan.

i am certainly no expert but i agree with this. i am upside down compared to the OP. i had a PM only because i had a smart trainer, i just got a HRM. i could have used it as a proxy for power but there is nothing like having the real thing to guage your effort by. however you the OP measures FTP i would do it, he can always adjust as you say.

-scott

i'll add that when out on the road i will need to use the HRM as a power proxy. with more use on zwift with power and heart rate i will have some good numbers to use as reference points.

I just ordered a powermeter and an HRM this week. I've never had either one before. Any recommendations on reading material or other resources to get started? I ride outside this time of year if that makes any difference.

When I started researching this, probably the most useful thing right at the start is learning the zones. I made some notes of all the various sources I found online, and the first thing is a table of Coggan's power zones and the various physiological adaptions occurring from training in each zone below that. I also found Tom Bell's free stuff quite good, there's a pdf including some sample workouts for the different zones and explanations (and actually a lot of websites that suggest workouts, are identical or very close to these few sample ones). Maybe use that as a starter maybe, and take your research from there. Maybe you get hooked, at some point I was definitely more into researching and planning than actually riding (but maybe that is who I am, I love to plan).

https://www.amazon.com/Training-Raci.../dp/1934030554

More than you'd ever want to know.

The most important research you can do is on the bike especially outdoors. Ride and watch what it does. As you get some miles on these gadgets, and especially hill miles, you'll figure it out The PM tracks training, i.e. effort. The HRM tracks the physiological cost of that effort, and also the cost of past efforts. The idea is that having more data will enable one to make better decisions about what to do in the moment as well as what to do in the future. That means you have to have someplace to upload your data, tabulate it, and use it to predict future results. I use TrainingPeaks Premium, there is other, similar software. It takes experience to figure all this out. You can't do it just by reading, you need a body of work on which to apply these tools. So figure out what software you want to use and start using it.

If you're not on a training plan, spend the first week just riding like you normally do. Observe the power numbers, get a sense for them. After a ride, look at the power data. Use software that graphs your avg power over time, again it just helps solidify everything. This will make the learning curve easier.

Your computer should be able to show you power averaged over X seconds and that's more meaningful than instantaneous power.

Whatever he's using now. He asked if he should redo the test, so he's got some number for now.

It's a good question, you make excellent points, but that's for down the line because (1) an FTP test is very hard and will fatigue him for several days, throwing off subsequent workouts and that's going to hurt the training more than starting with the wrong FTP number, and (2) because most people need to take the test a few times before they get the hang of it. Better to just adjust the FTP up or down based on if the intervals are too easy or hard - in the beginning while already into a training plan. I would say do the test sooner if not already following a plan. Good plan should include FTP tests every month or two (?) to measure progress anyway.

Ah, I misunderstood his post. I guess he's done an FTP using the Zwift sensor and now will have 2 sensors. I get it. I use the CTS protocol, accurate enough and back to the intervals with 1 easy day.

I will chime in...….

I am no elite athlete, not even close. I have a power meter and its been awesome. Here was my PM training build up to get better.
For the first 3 months I just rode like normal, getting used to the numbers, playing with it you know feeling it out. After 3 months I did a FTP test, the 20 minute one. Then about two weeks later or so I did the full hour version. I used those two tests to get a pretty close FTP I thought.

Then I got a book......yep, used a darn ol book and put together a training plan off that. I would have to go find it, only used it that one season. Now I have a decent regiment and know what the data means and how to use it. Been an awesome tool. I am still no athlete but I am a much stronger rider than I was before a PM. I can't see not having one now. I can climb better now, and know when to go and when to whoa.

It doesn't matter what power meter source you use, an actual PM on the bike or a trainer, as long as you measure with the same PM you will be able to track your progress. That is what's important. So yes, I would redo a FTP and use that only as a measurement. Zwift power measurement is actually pretty close if you compare but they are just a touch elevated I find comparted to my PM.

And the best part IMO they are just so dang cool to measure your watts!

I assume the second edition is good enough for someone just getting started?

Hah. I’ve had it so long I didn’t even realize that there’s a newer version.

I ordered the 2nd edition for under five bucks. Who knew ebay had such great deals on used books?

Thanks. I'll wait to re-do the FTP test, and just keep following the training program as is.

FYI, heart rate can be a good proxy over the long term, but for short efforts it responds too slowly. The great thing about power data for short intervals is that it's immediate.

for sure!! HR can be a tool BUT you have to use such a large sample over long period of time to get a number. Your HR can change on a day to day basis on so many factors.

I tired this approach at first before a PM and found it was hard to get solid consistent usable data.

Agreed.

i still have a lot to learn now that i am gathering data. below is from a zwift training i did a couple of days ago...

before i really started looking at the data i made the incorrect correlation that a rising heart rate indicated increased power output, not so according to the big circled data. the small oval is what i had expected every time (black == power, red == heart rate).

and what is your definition of effort vs long effort? a small 15 second micro burst of power being a short effort? based on what i see below i would agree.

https://cimg6.ibsrv.net/gimg/bikefor...e6307bf328.png

I gather that the gray area is the proxy for altitude, but what are the dark and light green lines? Rising HR is a result of accumulated stress. Of course if you hold a power that's greater than what you could do for a long period, your HR climbs for a while. Unless you are riding at an unsustainable power, eventually HR will stabilize if you hold power steady, although over a long period HR will gradually edge up depending on conditioning and hydration. This is called decoupling, that is HR that doesn't reflect a steady power output. Conditioning decreases decoupling to quite a degree. Cadence always affects HR, higher cadence at the same power will show a higher HR and vice versa. Though even all that isn't totally true. Over longer periods, the length depending on conditioning, hydration, and fueling, HR may be lower at the same power levels compared with 3 or 8 or 15 hours ago, just from exhaustion. There's a lot of information in HR, more information density than power really, just not always the information one expects to see. I mean that power only tells you one thing. HR tells you many things.

Congrats on getting a PM. I think you will like it a lot.

Since you already did an FTP test on Zwift, I would redo it. It is great training and it will serve as a starting point. Plus, it will take away one variable which is, what is my power FTP. You know how you felt after your previous Zwift FTP test.

Read Racing and Training with a Power Meter and do some searches on FTP testing and training. There is a lot of interesting articles. Since you will know your FTP, the theory and practice of power training will make more sense. It is not that hard to understand and execute.

What I found when I started training with power was that I was not generating as much force on the pedals over time as I thought I was. Heart rate and level of effort are okay but not great for determining pedal force. If there is an analogy, it would be that in the gym, I would bench press whatever, 100 pounds. I know it is 100 pounds and the force required to lift the weight remains the same. As I do more reps and sets, fatigue causes the level of effort to feel like it increases when in fact it is the weight is the same. I swear someone is adding weight.

On the bike and during a structured interval, fatigue caused my brain to think that I was continuing to make MORE force as time progressed but in fact, the force was DECREASING. Like the weight in the gym, power is a true measure of force.

As an added benefit, over time, my brain recalibrated and today, I am much better a riding a level of effort interval and can pretty accurately, know what my power is and not have it decline.

So how does that benefit my training? I work harder with more effort at the end of the interval when it counts the most. Good luck.

Power is the product of force times speed. Power changes not only by varying the force on the pedal; but also, by changing cadence. Similarly changing the force on the pedals with an offsetting change in cadence means power can remain constant as force changes. Power alone is in no way a measure of force.

(by the way, even in the gym, weight isn't a measure of force as the weight is accelerating)

For anything under about a minute, heart rate isn't useful in real time, because HR itself isn't in real time. It's roughly an average of what you've been doing over the last 30-60 seconds. Does that matter? Depends what you're doing. Tabata intervals, yeah, HR responds too slowly to be a useful target to titrate your effort at the time.

I'm not trying to talk you out of using HR, just filling in some technical detail so you or anyone else reading this can get better use out of their stuff.

You can use a power meter to pace yourself in a long term way, by modeling your fitness and cumulative fatigue. So if you have an important ride coming up and want to perform well, you can do a better job of scheduling workouts to be at your best on that specific day. And even though I have a power meter, I use HR for this instead.

To expand on this in a more general way:

Most people don't hold a steady power when they ride. That's why almost everyone prefers to see the avg over the last X seconds instead of just at that instant. It jumps around a lot. It's like you benched 100 lbs, then 120, then 97, then 20 for a second while you changed your position on the saddle sightly, then 140, etc. Except on a bike, it's like you're benching whatever is on the bar at that moment, but the plates don't have numbers do you don't know how much you're lifting. Each pedal stroke has a different amount of force. (Not usually huge differences.)

A power meter is like a scale so you know exactly what you're pressing. HR is how it's affecting you. Heart rate is influenced by things that aren't relevant to training. You want to be bench pressing 100 pounds whether you had too much coffee today or not, so when you're at the gym you go by weight not HR. I'm not saying you have to use power and ignore everything else, I'm saying people should be aware that HR and PWR are measuring different things.

Maybe you should stop and understand the difference between force and power as well as how they relate to each other. Each pedal stroke could just as easily have constant force and slightly different speed as power jumps around.

the blue is cadence. the green is speed (which i should have suppressed since it was not relevant, or so i think).

Steady power is really easy on the trainer. It's way harder out on the road. It's not that cadence is varying so much as it is that force is varying. We seem to have pretty good speed sensors in our legs. Micro variations in road grade and wind cause us to increase force in order to maintain speed and cadence. Possibly that is more evident in those of us who have practiced holding a steady pace. Riding a paceline, nothing is more frustrating than a lead rider who doesn't hold steady. I admit to being shocked at the power variations at a steady speed and cadence when I first went out with a PM, which was after weeks of roller work with that bike and PM.

I would also like to stress that everything that we see on our HRMs is relevant to training. The variations do take a lot more experience to interpret than does power, but that doesn't change their relevance. They only seem random if one doesn't understand what's going on.

We could describe this whole thing in terms of the movements of trillions of subatomic particles, but that wouldn't help anybody understand anything. Especially when a simple and accessible analogy gets the relevant points across.

But thanks for the very minor correction, it's a good point overall to remember force and cadence together make power and you can vary them both to get to the same place.

I've just started using a power meter in the last couple of weeks. Although it should have been obvious, I discovered this fact -- instantaneous power is constantly and quickly fluctuating. One of my Garmin Edge screens shows instant power and average power. How many of you find instant power a useful metric during the ride as opposed to, say, 3 second average? I want to learn how to better control and smooth out my power output. I think my choices for the data field are instantaneous, 3 second average, 10 second average, and 30 second average (which is obviously too long).

Separately, does anyone make use of Garmin's proprietary "Normalized Power" or "Intensity Factor" metrics?