The Road Bike Rider newsletter regularly appears in my inbox, and in it is usually an article by my favorite coach, John Hughes. In a recent article, he answered a question from one of his clients, a 70 year old man (the same age as me.) The question was "Why Do [my] Legs Hurt?" His response was pretty harsh, he pointed out to his client that he had not followed Hughes' directions, but rather had ridden more than he was supposed to, thus the sore legs. I felt rather sorry for the client for being publicly shamed, but at the same time noted that I had been feeling worse than usual and wondered if I deserved a tongue lashing as well. So I looked back at my recent logs to see if I have been faithfully following my own training schedule.
I talk a lot on this blog about "listening to my body." My body "speaks" to me in two way: how I feel (tired, sore, energetic, moody...) and how I perform (speed on a standard ride.) Listening to my body has been the only way I have found to figure out how much and how hard I should be riding, but it is not a panacea; my body cannot design a cycling schedule for me, it can only tell me if the one I am riding is too hard. Furthermore, by the time I get feedback from my body, it may be too late. By the time I feel the effects of overtraining, I may have already built up a fatigue debt that will require me to cut back significantly on my training, perhaps even for months. Thus, it is important that I carefully design and stick to a training schedule to keep that from happening.
How did I come up with my current training schedule? When I moved from Texas to California three years ago, many aspects of my cycling changed. The hills of California made it more difficult for me to do rides at well defined intensities, so I switched to a more "just ride" strategy, relying on those hills to give me the mix of intensities that cycling coaches recommend. So designing a schedule became making a list of local rides that together kept me fit and healthy but which were sustainable so that I did not drift into overtraining. This schedule consisted of a list of the rides I would be doing each week: Alpine on Monday, Cañada on Wednesday, Stafford Park on Thursday, Neighborhood on Saturday. Each ride has a distance and an amount of climbing; 23 miles and 1300 feet, 34 miles and 1800 feet, 7 miles and 200 feet, 12 miles and 500 feet, respectively. From experience, I know about how about how long each ride will take me, 110 minutes, 160 minutes, 40 minutes, 60 minutes. Thus, my schedule provides for 370 minutes of riding containing a reasonable mix of intensities. By listening to my body, I can determine if this schedule is too hard and adjust if necessary. But what if this schedule is not as consistent as it seems? In particular, I don't always ride the same route at the same speed, what is the impact of riding a particular route fast or slow?
It is fairly obvious why my speed might matter. The fatigue generated by a ride is a function of both how long the ride lasts (volume) and how fast I ride it (intensity.) The problem is how to quantitate the intensity of a ride. It is clear to anyone who has done such rides that a 20 mph ride is more than twice as tiring as a 10 mph ride, but how much more? Training intensity is normally described in terms of zones. The zone in which one is riding can be determined by measuring relative heart rate, relative power output, or subjectively, using relative perceived exertion - how hard the ride feels. Many coaches provide tables that list the heart rates and power levels at the boundaries of the different zones or that describe how each zone feels. There are some differences but a lot of commonality between the tables provided by different coaches. Coach Joe Friel, one of the first coaches whose books I read, uses a seven zone system, naming the zones 1, 2, 3, 4, 5a, 5b, and 5c. Historically, this is the zone system I have used on this blog. Coach Hughes, who I now follow, uses a six zone system, naming the zones 1, 2, 3, 4, 5, 6. The Hughes zones are very similar to the Friel zones except that Hughes combines the Friel zones 5a and 5b into zone 5 and names the Friel Zone 5c as Zone 6. As of this post, I am switching from the Friel zone system to the Hughes zone system. Back in Texas, I determined the zone in which I was riding using heart rate (HR) but since moving to California, I determine my zones using relative perceived exertion (RPE). (I have never had the pleasure of using a power meter.) What is missing from all of these zone systems is a quantitative measure of the impact of each zone on fatigue, fitness, or health, the three main consequences of training.
As I have previously blogged, I deeply distrust the metrics used to translate training zones into quantitative intensity levels in the training books I have read. Rather, my estimates of quantitative intensity has been heavily influenced by a paper I reviewed not once but twice on this blog, a paper I refer to as Gillen et al. This paper looked at the impact of intensity on health. The dramatic claim of this paper is that 1 minute of training in Zone 6 (High Intensity Interval Training or HIIT) has the same health benefits as 45 minutes of training in Zone 2. Even if one accepts the claims of Gillen et al., it is not clear that training in Zone 6 would also have 45 times the impact on fatigue and fitness as training in Zone 2, but in the absence of better data on the topic and for the purposes of this post, I am going to both accept the claims of Gillen et al. and assume that they apply to fatigue and fitness as well as to health.
Gillen et al. only compared rides in Zone 2 and Zone 6. However, a long standing claim of the medical community is that vigorous rides (Zones 3 or 4) have twice the benefit of moderate rides (Zone 2), so, relative to a ride in Zone 2, arbitrarily set to an Intensity of 1, I set the Intensity of Zone 6 to 45 as per Gillen et al. and then Zones 3 at 1.5 and Zone 4 at 3 interpolating and extrapolating the "Vigorous" intensity of the Medical community. To estimate values for Zones 1 and 5, I plotted the values for Zones 2, 3, 4, and 6 as determined above, connected them with a smooth curve, and read intensities for Zones 1 and 5 from the graph. In the case of Zone 1, I adjusted the value because didn't match my experience and common sense. The graph gave Zone 1 an intensity of 0.1. The medical community might agree with that value in terms of impact on health, but my experience says that the impact on fatigue is greater than that so I arbitrarily assigned it an intensity of 0.5. These values are listed in the figure at the top of this post.
I feel like I can do a fair job at estimating my RPE at any point in a ride, but what I cannot do with any degree of accuracy is to say, over the course of a variable and hilly ride, what percent of my time I spent in different intensity zones. Four or five months after moving to California, I wore my heart rate monitor on my Alpine ride. By chance, the speed I rode that particular day was my average speed for that ride, 12.3 mph, making this data maximally useful. The software that came with the monitor gave me the percentage of my time in each of the intensity zones as determined by heart rate. This was the data I used to determined that a mix of rides in California would give me approximately the mix of intensities that most coaches would recommend. Shortly after I did this measurement, my heart rate monitor died so I have no way at present to determine how this might change as my ride speed varies. Is there some way I might estimate that? Back in Houston when I was riding around and around the Rice track, always with a heart rate monitor, I did an experiment where I started riding at a heart rate of 120 bpm, recorded my speed, then increased to 130 bpm and 140 and so on until I reached a maximum heart rate of 173 bpm at which point I was riding at 23 mph. From that I concluded that each heart rate zone corresponded to an increase in speed of about 1.5 mph. Applying that to my current Alpine ride is quite a stretch, but in the absence of any better information, I will assume that if I increase my speed on the Alpine ride by 1.5 mph, the intensity zone of the various segments of this ride (uphill, downhill, flat, ...) will increase by about one, e.g. Zone 2 becomes Zone 3 and so on.
So how much does my speed on my Alpine ride vary? As I blogged last time, the last three months have included both the fastest (14.1 mph) and slowest (11.3) speeds on that ride. What determines how fast I ride it? The speed I ride is determined by how I feel. If my legs are feeling strong and I am feeling motivated, I might ride at at an average speed of 14.1 mph. If my legs are sore and I am not feeling motivated, I might ride at at 11.3 mph. I do confess that internal competition has a lot to do with it. If I ride it faster than 13 mph, I feel like that means I am in good shape and it makes me feel good about myself, so when I feel up to it, I am highly motivated to go for a fast time. To be clear, in all cases I am "just riding", even the fastest rides are fun and comfortable. That is not to say that the fast and slow rides are the same as measured by RPE. Even if the faster ride is more comfortable and more fun than the slower one, using RPE, I can definitely tell that the faster ride is harder. And this brings me to the point of this post: what impact does this variable ride speed have on my carefully planned ride schedule? For the sake of simplicity, let's consider two rides, the average 12.3 mph ride for which I have heart rate data and an hypothetical ride at 1.5 mph faster, 13.8 mph. If I take the percent time spent in each zone for the 12.3 mph ride and increase it by 1 as described in the previous paragraph and then translate each of these zones to an intensity as listed in the figure at the top of the post and sum the intensities over the two rides, this indicates that the 13.8 mph ride generates about twice the fatigue of the 12.3 mph ride. This calculation rests on a lot of shaky assumptions stacked on top of one another and therefore is highly suspect, but I have to say, the result feels right to me.
In retrospect, the conclusion of this analysis seems obvious: if I want to avoid overtraining, I should not ignore how fast I am riding. If I want to get the right balance of ride intensities from the hills of California, I need to have that set of intensities be consistent which means riding at a consistent speed. A week where I ride my two longest and hilliest rides at greater than 13 mph is a very different week than one where I ride them at less than 12 mph. How could I have missed something so obvious? It is, I think, because I viewed ride speed as a "message from my body" telling me, on a day I rode quickly, that all is well. While true, it is also true that how fast I ride is a decision I make which affects my training outcome. Another factor was by my natural competitiveness, I really like arriving home with an average speed over 13 mph. Do I now have to become a mindless drudge, reigning in my enthusiasm and squeezing all spontaneity and joy from my rides? Maybe not, maybe there is a middle ground. Perhaps it is OK to go all out on Monday and see how fast I can do the Alpine ride on a day when I am feeling strong, but then on Wednesday, I should make a point of holding back on the Cañada ride even if I feel like I could be riding it faster. Moderation in all things, as my Grandmother used to say.
So is this the answer to the question that inspired this post, are my annoying periods of feeling tired the result of prior rides that were ridden too fast? My intuition tells me that, at most, this is only part of the answer. It is certainly the case that coaches warn over and over again against exercising more than you think you are, more than you should, and there is the statistic that 65% of cyclists train too much as compared to 25% who train too little. Still, there are other potential reasons I might feel tired: stress from things going on in my life, a sub-symptomatic illness, or trying to ramp up my training too rapidly at the beginning of the season. But at the very least, being aware of the impact of my ride speed on fatigue gives me one more way to respond to the signals my body sends me.
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