How to use a power meter and smart trainer
by John Bye
So you bought a power meter — what do you do with it?
I originally got a power meter as everyone I was riding with had one and they would talk about how great it was and how it was a game changer for training and racing. For me, beyond knowing that power is the rate at which energy is used (energy over time) and is measured in watts, at the time, I had no idea what to do with it and the power meter wasn’t turning the wheels for me.
There are all kinds of articles available to you on how to use power for training and racing, but what I intend to do with this one is to focus on a few key points to help you get comfortable leveraging what a power meter is telling you and how you can leverage it and your smart trainer to get massive gains in capability.
In simple terms, when you are biking, you are essentially a turbine engine creating power that is pushing the bicycle forward.
Power is measured via two things:
- The force with which you are pushing your pedals on the downstroke of your stroke cycle
- Your cadence
As an example, when you are climbing a hill, you can, to maintain a certain level of power generation to move you up the hill, either mash your pedals in a high gear as hard as you can or use a low gear with extremely high cadence. The trick with riding is to figure out how to optimize your gearing so that you are working your legs at a sustainable level of effort and doing so at a reasonable cadence you can consistently hold.
The information captured by the power meter is most often leveraged to provide a measure of your overall cycling capability that is referred to as your Functional Threshold Power (FTP). Your FTP is simply how much power, on average, you can generate over the course of an hour. Therefore, as it increases, so does your overall speed.
This number is extremely useful. With it, you can manage your overall effort for a given ride and can figure out what your bike split will be for a given distance. If you go online, you can easily find calculators that you can input your personal capability data and course information and it will tell you how long it will likely take you to ride the course. These are crazy accurate.
I have never been a fan of long, slogging rides indoors; i.e., "mindless spinning." Are you better off, rather than sitting on your couch watching a movie, to do so on your bike, spinning? Absolutely. Although, you could get more out of an easy long run in a third to half the time spent.
However, say you have 45 minutes to an hour, total for a workout. If you are going to ride outside, it takes awhile to get your bike ready and get going; then, you have to deal with the weather, mechanicals, stopping for stop lights and signs as well as dodging cars, people, dogs, etc. Your time can be more productively managed with structured interval training on your smart trainer which will, in turn, provide massive improvements in your overall biking capability.
The advantage of the indoor, smart trainer is that it allows you to do structured interval sets with targets based upon percentages of your FTP.
An example of a 45-minute set:
- 10 Minutes of warmup
- 30 Minutes of structured sets (i.e., sets can be around 20 minutes of work with 10 minutes recovery in between; e.g., 4x5minutes at FTP with 3-to-5 minutes of recovery)
- 5 Minute cooldown
- Then tack on a ½ mile to 1-mile transition brick run for fun.
Do this consistently by varying your interval sets and recovery so that they all equal about 30 minutes of work and you will see gains.
You can certainly execute your workout, then, afterwards, see how you did, but a valuable way to immerse yourself in your ride is to set your bike computer up to show measures of how much effort you are undertaking for a given interval. This will allow you to, in real-time, see whether you are hitting your target and, during, can see if you are maintaining power as you are riding or need to work harder to hit your target.
On the first screen:
- Lap Normalized Power (NP) – The measure of the work you are doing for a given ride. So, think of it, like in running, as your average overall pace. You use NP rather than Average Power as NP accounts for the variations in resistance due to elevation, terrain, and other factors to provide a truer measure of effort. So, your Average Power will always be less than your Normalized Power, except when you are on a flat course and pedaling the entire time.
- Power Ave 3s - The average Power generated over a 3-second period. Think of it, like in running, as your current pace. If you just use “Power”, you will find that it jumps around like crazy and is really difficult to follow as an instantaneous measure; therefore, to mitigate that, you can use “Power 3s Average” to get a better indication of what you are currently doing.
- Lap Time
On the second screen:
- Lap Normalized Power (Lap NP)
- Last Lap Normalized Power (Last Lap NP)
In this way, at the conclusion of every interval, as opposed to, when you are done, reviewing your data, you can hit your split button to capture the information. You can then see, during your rest interval, how you performed on the previous intense interval by viewing Last Lap NP.
Then, you can quickly record your data on a piece of paper next to you. Seems like a redundant exercise; however, in practice, throughout the workout, you can, in real time, track how they are doing by set, by interval and will know whether your overall interval wattage is going up or down. The idea is to “Crescendo” your workouts; that is, ensuring that your last interval outperforms the first.
Tracking in real-time throughout gives you that information at your fingertips; and, if you keep it in a notebook, you can quickly go back and look at historical performances of similar workouts and see how you stand. Through this, I always have found my athletes that keep track as they go are always have more productive workouts than those that do not.
In short, it is hard to get motivated to train in the early season, especially when the weather is challenging; however, your Power Meter and Smart Trainer are tremendous assets that will allow you to be extremely productive with your time spent working out.