The book is a huge thick volume, and is chock full of diagrams, graphs, etc. It's mostly targeted for the coach, but obviously that applies to you as well if you're self-coaching. The graphs and technical what-not look intimidating, but I think I can distill the use of power meters in training as follows:
- You can use it to establish a baseline power called the FTP --- Functional Threshold Power, which is basically the highest sustained power you can maintain over a period of about an hour. The protocol for doing this is complex and sounds painful, but fortunately you can download an app to your Garmin watch/head unit that'll give you a fairly accurate assessment in a few minutes. Obviously, you can't do this without a power meter.
- In conjunction with a heart rate monitor, the power meter can tell you whether you're over-stressed (overtrained) or under-stressed (i.e., could stand to work out harder). Basically, if you can maintain or even increase your power output at the same heart rate as before, you can up the intensity/volume of your training without risking being over-trained. Conversely, if your heart rate is high but you have trouble sustaining your FTP, then you're over-trained and should back-off. This is actually of limited use to a self-coached cyclist, as you can judge for yourself whether you're tired. But hey, the data can be there to for you to recognized that you truly are tired, not that you're being lazy, and so might encourage you to rest more than you would otherwise. (Resting is apparently something very hard for the type-A race winning cyclist to do)
- Over time, you can see whether your power is increasing, which tells you how effective your training program is. Conversely, by checking your power output sustainability (basically, graphing your power output over time), you can find out how fresh (rested) you are. For instance, after a tour of the alps you might be very fit, but you certainly are not fresh. A week of rest later, however, your fitness might have dropped, but your freshness means you can go out cycling and break all your PRs on the local hills. Being able to track all that means that you can personalize exactly how much rest you need in order to have maximum freshness for a big event. (Known as the "taper")
- Finally, during the event, you use the power meter to pace yourself, so as to not exceed your FTP too often or for too long. Doing so burns one of your "matches" (and yes, you can use the power meter and a training regiment to figure out how many matches you have, and increase the number of matches you have), and you will not be able to sustain that pace for very long without damaging your overall power output.
And indeed, if you look at those 4 items above, you'll see that there's no reason to buy an expensive power meter --- the cheap unit (yes, it's in the book) will work just fine!
OK, did I just give you the short summary of an $18 book for free? Of course not. The devils are in the details, and the book mostly provides graphs, charts, and case studies on how to build a training regiment that's effective. It even classifies cyclists according to their power curve to be able to more easily customize an effective program for you and the type of riding you do. I discovered, for instance, that I was a sprinter-type (not a surprise: 23 and me told me that several years ago), but unfortunately, there's no training program that'll help a dad who has to carry 2 kids on a triplet over a 3 week tour. All the training advice seems geared to cyclists who are targeting a one day event, and who's racing for prizes, positions/whatever. I'm just trying to enjoy myself and have a good time while grabbing photos of the scenery, and there's no training program for that!
You don't even have to read the book to make use of the information. There are two major websites, Training Peaks and Xerts that will suck in your data from Garmin or Strava, and then either spit out a training plan to sync (Xerts) to your Garmin Edge automatically (watches not supported or I'd be tempted to try a 'structured workout') or let you buy a training plan/link to a coach (Training Peaks) to help you achieve your goals. Xerts claims to be powered by machine learning, and I wish they supported my Fenix 5X so I could see if their stuff worked, while Training Peaks seems to basically be an advertising platform for remote sports coaches to charge you hundreds of dollars a month to torture you, which is something I would think that I would pay to avoid, but of course, as one of my friends once said to me, "The problem with you, Piaw, is that you want to enjoy the ride! Don't you know that if you don't feel like throwing up you didn't go hard enough?" If that last statement describes you, don't walk, run to your web browser, buy the book, power meter, and head unit and go to it! If you don't think that enjoying the ride is a problem, then this blog post probably describes everything you needed to know about power meters.
P.S. It turns out there's a chrome extension (Elevate for Strava) that graphs and tracks your power development, fatigue, fitness, etc for free by scraping your data off Strava and storing it in a Chrome sandbox (i.e., it's not online, doesn't depend on servers and you have to manage saved files manually and back it up manually). One of my friends used it with great success for this year's PBP. It looks much easier to use but won't suggest workouts, etc to optimize your training.
P.S. It turns out there's a chrome extension (Elevate for Strava) that graphs and tracks your power development, fatigue, fitness, etc for free by scraping your data off Strava and storing it in a Chrome sandbox (i.e., it's not online, doesn't depend on servers and you have to manage saved files manually and back it up manually). One of my friends used it with great success for this year's PBP. It looks much easier to use but won't suggest workouts, etc to optimize your training.