Wednesday, January 22, 2014

Extreme Decoupling

A Modesto Roadmen training ride in1967.

Since the collapse of by randonneuring ambitions, ambitions which had previously defined how I cycled, any kind of training or even regular cycling program I had also collapsed. Since then I have been trying to develop a new training plan. That training plan is not an end unto itself, of course, the reasons I ride my bike are to stay healthy and to have fun; everything else is in service to those goals. The goal of my training is to provide enough exercise to stay healthy and to get me sufficiently fit to engage in as many fun rides as possible. I have gotten lots of valuable training advice from my readers for which I am very grateful, but of course I have to be the one who ultimately decides which of that advice applies to me, an old man with a badly neglected body. This post is an update on my current thoughts on reconstructing a workable training plan for my future.

Why train at all, why not just ride for fun? For that matter, what is the difference between training and riding for fun? There need be none, of course, if one is enjoying their training rides. To me, however, that "if" defines the difference; a training ride is a ride that you do if you are enjoying it or not, and that you do in a particular way (e.g. speed, distance) independent of what you might prefer. To put it another way, I very much fear that if I only rode my bike when it was fun, I would not be doing enough riding. So to answer the question, I train to make sure I ride enough to get the health benefits I am looking for and to get as fit as possible; as fit as possible because the fun rides I want to do are longer and faster than I can manage today. All of that said, it wouldn't bother me a bit if I found the required training fun.

As a starting point, I wanted my training rides to satisfy the American College for Sports Medicine's (ACSM's) recommendations for healthy adults. There are a number of different ways that could be structured (and I hope to experiment with some of those going forward) but for the moment, I am experimenting with daily MAF test rides to reach that goal. I have given a great deal of thought to MAF tests and have convinced myself that a MAF test ride qualifies as moderate exercise (equivalent to a brisk walk) and thus I should ideally be engaging in 300 minutes a week of MAF tests; a 45 minute MAF test ride almost every day. The "test" part of the MAF test, measuring and recording my average speed during the ride, is not relevant to the ACSM recommendations, but it does make the ride more fun and will, I hope, help guide my future training. On the other hand, wearing a heart rate monitor and riding at a fixed heart rate is an important part of meeting the ACSM recommendations. I use my heart rate monitor to make sure I don't ride too fast (easy for me to do) and that my MAF test rides are truly moderate intensity. (One more example of a difference between a training ride and a fun ride is that a training ride might be done while wearing a heart rate monitor whereas a fun ride probably will not.)

Let's Have Fun!

Why does recording my speed make my otherwise boring MAF tests more fun? The fairly obvious answer is because it provides a goal. As I ride, I note my speed and notice if I am having a good day or a bad day and if I am improving overall. That adds some interest to the ride and reduces the boredom by providing a goal. But that's not why I started tracking MAF test results. I started tracking MAF test results to monitor my training after reading Phillip Maffetone's "The Big Book of Endurance Training and Racing". The concept in that book is that it is important to train at a relatively low speed, aerobic threshold or zone 2, to avoid overtraining, and that the success of this approach should be reflected in continuous improvement in a MAF test results. What Phillip Maffetone did not say was that the training rides should be MAF tests, which is what I am currently doing. Although both MAF tests and Maffetone's recommended training rides are ridden at the same speed, the MAF tests are 45 minutes long, whereas the training rides can be longer. My use of MAF tests as training rides satisfies ACSM's recommendations for health maintenance, but do they represent optimal training towards my second goal, maximizing fitness? To anticipate the rest of this post, almost certainly not.

One piece of advice I received on this blog was from skiffrun who said the following: "Throw all that training literature away -- it isn't written for someone 60+ years old with a fairly high resting pulse (60+), anyway." It is also not, by and large, written for a non-competitive endurance cyclists, but for racers. That said, I can't bring myself to throw it all away, I feel like there is value there, I just need to understand it and extract the bits that are relevant. Based on that belief, I turn to Joe Friel, one of the most respected authors of training books today. Friel's "The Cyclists Training Bible" does not (as far as I can find) recommend a test similar to a MAF test. Rather, Joe Friel's measure of endurance and aerobic fitness takes advantage of a poorly understood yet widely observed phenomenon called "decoupling." Ideally, heart rate during exercise should increase as effort increases. However, there are circumstances where that relationship breaks down. If one rides at constant heart rate, at first the power generated (roughly reflected in the speed you are riding) will be constant but eventually will start to decrease, a process called decoupling. Although this is a "bug" in terms of using heart rate as a measure of effort, it turns out to be a "feature" in terms of measuring endurance. Joe Friel suggests a test where you ride at aerobic threshold and record the time at which decoupling first starts to appear. You then include increasingly long aerobic threshold rides in your training until you can ride for two hours without seeing any decoupling. I'm not sure if the two hour figure is particularly relevant to me, but the phenomenon of decoupling definitely is. I first noticed decoupling about a year ago, when I first started using a heart rate monitor. Just like today, my training then consisted mostly of daily MAF test rides. Although I did not notice decoupling during the 45 minute MAF test rides, I also wore my heart rate monitor during longer rides as I added them to my schedule and then I did observe decoupling:

Data from Garmin Training Center. Red lines added by hand.

The above graphs, reflecting data downloaded from my Garmin, are from the first longer ride I included, a 30 mile ride. (A MAF test is normally 10 to 12 miles, 18 miles if you include warm up and cool down.) During this ride, I tried to keep my heart rate between 130 and 140 beats per minute (my heart rate at aerobic threshold, the same heart rate used for a MAF test.) I largely succeeded at doing that, though it did drift up a bit at the end. Because this was a ride not on a track but on a bike path, speed varied as I went up and down hills, crossed roads and stopped for traffic, etc, but seemed to vary around a relatively constant value for the first 1½ to 2 hours, but then dropped off noticeably due to decoupling. The heart rate monitor connected to my Garmin has stopped working again (details to be provided in a future post) and I have been reduced to using an inexpensive, stand-alone Polar monitor which doesn't record data and thus no longer have pretty graphs. However, this inexpensive monitor works fine for my MAF test rides and has proven to be very reliable. I used this basic monitor on a recent social ride with my wife, ridden a few weeks ago at the nadir of my fitness. It was a beautiful day, the George Bush Park/Terry Hershey Park trail is one of our favorites, so although we hadn't been riding much, we decided to go for a 37 mile ride. My wife is almost always a slower rider than I am, so the fact that we were riding together tended to keep my speed down. Even so, my heart rate drifted up over the course of the ride, and during the last few miles, ridden at a leisurely 12 miles per hour, my heart rate got up to 169 beats per minute. For perspective, this heart rate is higher than my lactate threshold heart rate (the junction between zone 4 and zone 5), a rate which, when I am fit, I only reach during during interval training (sprinting). Clearly, my heart rate at the end of that ride had nothing to do with effort but was reflecting something else entirely, something that Joe Friel claims and that my experience suggests has to do with a lack of fitness for long rides. According to Friel, the only way to correct this is long training rides. So, if I want to do fun rides longer than 20 or 30 miles, which I very much do, I will need to do include much longer rides in my training plan.

Besides decoupling, I have found that other anomalies in heart rate behavior seem to be indicative of my fitness. The first is heart rate stability. When I am fit, my heart rate increases and decreases smoothly with effort. When I am not fit, it will jump up and down, making it difficult to ride my MAF tests correctly. The second is the ability of my heart rate to recover during my cool down ride after a MAF test. When I am fit, during the 20 to 25 minute ride home from the Rice Track, I can easily get my heart rate below 110 beats per minutes, sometimes below 100 beats per minute. When I am not fit, it can be a struggle to get it below 120 beats per minute.

What I am not finding indicative of much of anything is my resting heart rate. Based on the advice of Iron Rider, I began recording a "true" resting heart rate about six months ago. By true, I mean I record my heart rate first thing in the morning while lying in bed. That heart rate varies between 55 and 70 beats per minute. I began measuring my "true" resting heart rate because Iron Rider suggested it might reflect my level of fatigue which I could then use to help plan my training. The concept is that my resting heart rate would increase as fatigue increased, and thus on days when my resting heart rate was higher, I should take it easy. It became clear very quickly that my resting heart rate did not behave in this way. However, I thought I detected a reverse pattern, that fatigue caused my resting heart rate to decrease. Because Joe Friel reports that this is one known difference between younger and older riders, such a decrease seemed plausible. However, this association has not held up either. I continue to measure my resting heart rate because I hope that a pattern will eventually emerge, but at present I can not make any use of it.

One final observation I have made is that I have found that I lose fitness very quickly, in a matter of two or three days. Joe Friel has reported that older athletes recover from exercise more slowly, and I believe I suffer from that as well. Joe Friel's advice to older athletes for dealing with slower recovery is more recovery time, but because I lose fitness so quickly, when I increase recovery time, I loose fitness. Thus, as I think about a training plan going forward, I am thinking of a "walking on eggshells" plan; one where I avoid ever getting too fatigued so I never need to allow a long time for recovery. I find that taking a day or two off a week can be beneficial, but any more than that seems to do more harm than good. In that context, I am struggling with the role of "brisk" (fast) training rides in my plan. Everyone seems to think these are helpful; Bicycling Magazine recently described them as the "secret sauce" in preparing for one's first century ride. However, when I have done them, I have not noticed much benefit. I wonder if, for me, they do more harm that good? A final issue that I will leave for a future post is what role periodization, especially on an annual scale, should play in my training. Stay tuned as I continue the quest for a training plan to get the most out of my decrepit old body.

No comments:

Post a Comment