The MAF Test Must Die

I believe that these MAF test scores reflect with a fair degree of accuracy the ebb and flow of my fitness in the four to five years since I have started riding MAF Tests. In 2012, 2013 and 2014, I found the cold and rainy weather around December discouraging and let my fitness slide. In 2015, I finally overcame that weakness, and maintained fitness during the winter. The smaller drop in fitness in June was the result of a wonderful family trip to Israel. By December of that year, my wife's cancer was approaching its tragic climax, and so I had less and less time for bicycling.

For years, the MAF Test¹ ride has been the workhorse of my training. However, starting this fall, I may never do another MAF Test ride again.

Am I abandoning MAF Test rides because I have changed my mind about the value of a MAF Test as a training ride? Not at all. I have always been optimistic but skeptical of the value of MAF Test rides, but I am no more (or less) skeptical now than I was 2 or 5 years ago. Is it because I want to try something different? That certainly could happen, but then I probably wouldn't assume I would never ride a MAF test again; depending on how this hypothetical new idea worked out, I might well go back to riding MAF Tests. So, I have not given up on MAF Tests, I am as enthusiastic about them as I have always been.

Is it because I have finally seen the light, and realized I had been misusing² the MAF test all along? No, it's not that either. I have known from the beginning that my definition and use of the MAF Test had little if anything to do with the ideas of its inventor, Philip Maffetone. Basically, what I am calling a MAF Test is something I invented, inspired by Dr. Maffetone. If it has any value, he gets all the credit. If it is valueless or even actively harmful, then the fault is mine.

So what is changing as of this fall that is driving the MAF Test ride completely out of my training repertoire? I am moving from Houston, Texas to San Carlos, California, that's what. San Carlos is on the San Francisco Peninsula, a mountain range that defines the western boundary of the San Francisco Bay. Finding a hill in Houston is a challenge. Finding a flat stretch of road in or around San Carlos is an equal challenge, and a flat stretch of road is what a MAF Test requires³, so no more MAF Tests.

How am I going to replace this workhorse of my training schedule? What will I ride instead? My philosophy is when in Idaho, eat potatoes and when in Georgia, eat peaches. In Houston, MAF Test rides made sense, and I believe I derived a lot of benefit from them. I think they helped me maintain and even build fitness while not stressing my body too badly. I think, because they were highly controlled and monitored, they helped me develop a good intuition and body sense as to what constitutes a moderate-intensity ride. However, in San Carlos, the weather is nicer, the scenery is better, the countryside is more accessible, and thus rides are more fun and interesting, and I think I should take advantage of that. Given the intuition and body sense I have developed, I think I can do moderate rides, even when confronted with the inevitable hills, by just listening to my body and taking it easy. I have already been spending a lot of time on the peninsula in preparation for this move, and I have been able to manage easy rides, party because my California bike, a Bianchi Volpe, has very low gears. Its lowest gear is 24 inches, as compared to 28 inches on my Texas bike, my (modified) Surly Crosscheck. This basically means that, on the Bianchi, when I get to what would be the lowest gear on the Surly, I have one more, lower gear to use. As a consequence, I can take it very easy up most hills, and thus can keep intensity moderate when that is the plan for the day. So, my best guess is that in California, I will be much less compulsive, but will identify some rides where the hills never get too out of control, where, by aggressively using my gears, I can keep effort moderate. I expect to wear a heart rate monitor much less often, but might wear it occasionally, ignoring it during the ride⁴ but looking at its record afterwards to see how good a job I am doing at keeping the ride effort moderate. My older son, Michael, thinks the answer to fitness and good health is to aggressively pick routes with the most insane hills possible and then to ride to exhaustion. I respectfully disagree, at least for me on a daily basis. However, if I ride with him every week or two, his rides will perfectly fill the role of the intense rides on my schedule. There are lots of beautiful, low traffic roads on the peninsula, so putting together long rides will be easy. By doing the right mix of these three kinds of rides, I should be able to reach the maximal level of fitness my aging body can tolerate. Finally, every town in the San Francisco Bay Area has at least one bicycle club, so once I am settled in, I may look for a club to join. Who knows, I may even give randonneuring another go. Stay tuned.

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1) For those of you fortunate enough to not have read all my MAF Test blog posts, MAF stands for Maximum Aerobic Fitness. The test is how fast one can ride while not exceeding the maximum effort that can be done completely at a heart rate where the ratio of fat burned to carbohydrate burned is maximized. It is designed to be ridden as a test of one aspect of fitness to be taken about once a month. The "test" is how fast one can ride while not exceeding that heart rate. As I use it, a MAF Test ride is done as a training ride; the test is secondary, the ride and the training gained from that ride is primary. This ride consists of warming up in Heart Rate Zone 1 for about 20 minutes, riding on the Rice Track, carefully keeping my heart rate in Zone 2 for 45 minutes (the MAF Test itself,) and then cooling down by riding in Heart Rate Zone 1 for another 20 minutes. Heart rate zones are as defined by Joe Friel. I believe that Heart Rate Zone 2 corresponds to the heart rate that maximizes the percentage of fat burned, but have not confirmed that by direct measurement. (To do so is a bit expensive.) 

Here are some of my blog posts describing the MAF Test:

• Fast Twitch, Slow Twitch, and Training Regimens
• A New Hope (Aerobic Training)
• Personalized Training
• MAF Test Revisited

2) Here are the ways I have been misusing the MAF Test:

a. I use it as a training ride. As its name implies, the MAF Test is a test, not a training ride. 
b. Because I am using it as a training ride, I perform the "test" much more often than I should. "You should not do the test more often than every month as you risk becoming too obsessed with analysing the results in those cases." (http://www.championseverywhere.com/maftest/)
c. Philip Maffetone has a very specific way for determining the heart rate at which the test is to be performed. Instead of using his heart rate, I use a significantly faster heart rate corresponding to Joe Friel's heart rate Zone 2.

I have reasons that seem sufficient to me for all of these changes, but since I am dropping this ride from my training repertoire, and because I have discussed this all before, I see no reason to repeat my justifications here.

3) In fact, the requirement for a MAF test is more stringent than that; it must be ridden on a flat out and back course with no lights or stop signs and no traffic that would interfere with the ride. Even though Houston is flat, I know of no roads within 30 minutes of my house that would qualify for a MAF Test. Part of the reason the MAF Test became such an important part of my training repertoire is the proximity of the Rice Track, a flat, traffic free course with no stops, the perfect site for this ride.

4) One of the reasons I like the Rice Track for MAF Tests is that, in my opinion, staring at a heart rate monitor while riding in traffic is recipe for disaster.

Sad News

A recurring theme on this blog is the interruption of my bicycling dreams by the realities of life. In some cases, I could explain this fully on the blog. In others, I could not. For example, when my Dad's health began to fail and I had to interrupt my cycling to fly to California to help care for him, I described that in great detail. However, when other things happened, privacy concerns forbade me doing so. Instead, I repeatedly referred to a cryptic post which only said that my cycling was being impacted by something about which I could not blog. Sadly, I now can. In April of 2015, my wife Agi, had her ovarian cancer recur. Ovarian cancer, when it initially occurs, is rarely curable; only 20% or so of women with ovarian cancer are cured. Recurrent ovarian cancer is never curable, so from that date forward, we knew what was coming, but I could not blog about it. Why not? Well, if you know you are going to die, then you have to decide how you are going to live the years or months or days that you have left. Agi, being the brilliant, brave, and practical person that she was, decided that ignoring her cancer was the only rational response, and to do that, the fewer people who knew about it, the better. Thus the title of that cryptic blog post was "I Have No Mouth, but I Must Scream." But now that Agi has finally lost her eight year fight against cancer, there is no longer anything to stop the screaming.

The picture at the top of the post was my wife's commuter bike. Back in 2012, we went through a long process of trying to buy her a commuter, defined very specific criteria for the commuter we wanted, and then never bought anything. (There may have been some cause and effect there.) Whether it was the many cycles of harsh treatment or progression of the cancer itself, by the summer of 2016, she was finding it more and more difficult to commute to work on her road bike, mostly because swinging her leg over the frame was becoming a challenge. At about the same time, Public Bikes had a sale on a very attractive looking commuter, one with a step-through frame which promised to solve that problem. Although we have previously said we would not buy a commuter that Agi could not test-ride first, we abandoned that principle and had them send us one. Agi loved that bike and was able to bike to work a few months longer because of it. In brief, I cannot recommend Public Bikes more highly.

And so, life goes on. For me, but not for Agi. Does this mean a return to regular blogging? Honestly, I don't know. What I do know is that is very much what Agi would want, so I will try with everything I've got. Stay tuned.

Is The Zombie Finally Dead?

Yes it is, Zombie, yes it is. (Zombie on tour, almost 50 years ago.)

"Killing Zombies is the act of rendering the moving corpse completely motionless once again. It can be argued that the term killing is technically inaccurate, as despite the observed locomotion of the zombie, all other life functions have ceased. Still, the point is mostly one of semantics. All you have to do is aim for the head, strike, and don't miss!" from Zombiepedia.

A blog which I follow regularly is "Lovely Bicycle". Lately, I have started to worry about its author because there have been no new posts on her blog for over a month, since April 5. And then it occurred to me, there have been no new posts to this blog for much longer, for almost four months, since January 27. So, the purpose of this post to reassure any readers I might have that my head remains intact and that I still maintain some locomotion, currently riding about 3 days a week. Over a year ago, I posted a non-explanation of personal events that were interfering with my cycling and blogging. Those personal events continue to evolve, not a good thing in this case. I still cannot talk about these events, but they have reached the point where I can no longer reliably post to this blog. I didn't decide not to post, it just happened. I will post again as soon as I can, though I don't know when that will be. See you down the road!

Progress Report: Braes Bayou West

Closed off section of the Braes Bayou Trail, heading west.

Wow. Oh wow. Two months since my last blog post. Worse yet, this is part 2 of a 2 (or 3?) part series which should have followed directly on it's predecessor. I still am forbidden to give any details, all I can say is that life is tough at Chez Zombie right now.

Last post, I described how, out of desperation, I started riding east on the Braes Bayou bike path, and how, when I did, found that it had been significantly improved since I last rode it, making it a delightful alternative when the Rice Track is closed. The one fly in the ointment was a collection of ominous "Path Closed" signs, not blocking the trail, but lined up along the side, threatening a closure at any moment. When headed towards that path for the second time, I was convinced I would find it closed, but open it remained. After a week of riding this path, I started to relax, which is when the axe fell. One day, I rode to the end, and as I headed back, found that the trail had been closed behind me. I begged the workman manning the sign to let me through so I could get back home, and he reluctantly agreed, but shook his finger at me saying "This is for your safety!" In an attempt to figure out how long this closure might last, I asked him why it was closed, which caused him to repeat "This is for your safety!" Blaming myself for having been unclear, I apologized, then explained I was just trying to figure out when I could use the trail again, invoking a third "This is for your safety!", this time at elevated volume. Not wanting to create a situation, I gave up, thanked him profusely, and headed home.

What to do? Rice Track closed. Braes Bayou West closed. Braes Bayou East closed. I tried a ride through the local neighborhoods, which was too short and didn't allow for the intensity I was looking for. I tried White Oak Bayou, which was lovely and delightfully long, but more than I can do on a regular basis. And then I reconsidered Braes Bayou West. Yes, the beginning of the trail was closed, but was there some way I could join the trail downstream of the closure? Indeed there was, and there was a surprise wait for me at the end of the trail.

My alternative route to the Braes Bayou, West bike trail. The route is took is in red. It is a loop, because it made sense to take one route to the trail and a different route returning from it. The normal route I take is in blue. The stretch of the trail closed at the time I made this switch is shown in purple.

The newer stretch of the trail going from South Braeswood (past Gessner) under Highway 8 has been on again, off again closed or open at different times I have ridden it. On this ride, it was open. When I passed under Highway 8 and proceeded to the end of the trail, I came across both a new sign and a new trail:

This sign would not have made sense previously, as there was no trail past this point to close. Now, there appeared to be a completed if not yet open trail, one that promised to cross the oh so important barrier of Highway 59 (a.k.a. US 69.) Should I proceed? To do so would appear to be a violation of the rules and promised to put me in conflict with angry construction workers. But nobody appeared to be around, and the trail looked completed. Maybe it would be OK to go just past the sign, and take a little peek?

Do not be deceived! Although the narrative might suggest that this is the trail proceeding under 59 heading west, I actually took the picture on the way back, so this is the opposite direction. No matter, both sides look the same and this picture makes my point equally well.

Although it seemed clear the path did proceed under 59 as I had hoped, the density of roadways make this underpass look dark and forbidding, a good place for an angry construction worker to hide. But I simply had to know; did this path really go past 59?

It did! Here I am on the other side of Highway 59, looking at the trail ahead. The orange barrier is there to prevent cyclists heading west to east from traversing the trail on which I had just come. It is not very clear in the picture, but the paved trail ends just past the barrier. I have marked the transition from concrete to dirt with the red arrow.

The map above shows just what this trail gets me (or at least will, once it is officially opened.) The red line shows what I rode. The yellow arrow is where the "Trail Closed" sign is, the previous end of the trail. The green arrow shows where the paving ended, at the time I did this ride. And promisingly, the blue arrow shows where I think existing trail picks up again.

So what's the big deal? A few more miles added onto the end of the Braes Bayou trail. Well, these few miles bring you to busy but rideable roads that take you to the trails around George Bush and Terry Hershey parks. Those trails take you to trails around Bear Creek Park. Those trails take you to busy but rideable roads that take you to the White Oak Bayou trails, which connect to the Buffalo Bayou Trails that lead you (with a gap or two yet to be filled) to the East end of the Braes Bayou trail, a circle about 67 miles in circumference, 53 of those miles on trails, 67 miles within the city limits of Houston, Texas. This is all diagrammed on the map below. Wowza.

Progress Report: Braes Bayou East

I am addicted to the Rice Track for my daily rides. The Rice Track is located in the middle of the Rice Football Stadium parking lot which means that during football season, the track is frequently unavailable, the space being used for parking. Thus, one day last October I showed up at the track only to find that it was closed. In the past, I would have ridden through the Medical Center to Braes Bayou, and headed west on that bike path for an alternative to riding the track. However, as is shown in the picture above, that trail was closed, so I tried going east. I haven't been going east due to gaps in the trail requiring riding on some nasty dirt stretches, and furthermore, the last time I tried, the trail heading east was closed, but due to lack of other options, I had no choice but to try.

On the left, the dirt trail before it was paved. The picture fails to capture how steep and treacherous this trail was. On the right, the same section of trail after paving.

Turning east onto the Braes Bayou trail, I was delighted to find that not only was the trail open, but that all of the dirt stretches had been paved! Thus, I headed east, albeit with some apprehension; a flood several months earlier had washed out a bit of the trail near the end. I reached the washed out section to find it still in need of repair. I followed the official detour, which required some backtracking, in that I had ignored the upstream detour sign to check out the washed out section for myself. On my way back to the detour, a young woman on a bicycle passed me heading the other way. I briefly considered calling out to her, warning her of the detour, and then decided that discretion was the better part of valour. As I proceeded along the other side of the bayou, I kept watching for her to turn around. Instead, I saw her disappear and then reappear farther down the trail, past the washed out section. Clearly, there was another, shorter detour, and I resolved to find it. The next day, riding essentially the same route, I did. By riding a few blocks on the street, it is easy to bypass this missing bit of trail.

If you look carefully, you can see how flood-induced erosion caused this section of the trail to collapse. The sections of concrete are tilted and disconnected one from another, rendering this bit of trail truly unrideable.

Starting from home, the trail heading east is shorter than the trail heading west. In an effort to extend my ride, I continued past my normal turn around point and continued into McGregor Park. For the past few years, I had avoided this extension because the old paved trail had been torn up as part of park repairs, leaving only a gravel detour. However, in addition to wanting to add a few miles, I was curious about a trail that supposedly extended past the park, but which I had never been able to find, so on I went. Imagine my delight to find that the trail through the park had been upgraded to a new, wide, smooth concrete trail.

A section of the resurfaced trail on Braes Bayou east of Martin Luther King Boulevard. Up to the truck is the nice, new concrete trail which ends just past the truck. When completed, this will be a nice trail indeed. Unfortunately, this resurfacing closed down a lower quality but rideable trail, reducing cycling opportunities in the short run.

The east end of McGregor Park is defined by Martin Luther King Boulevard. A new branch of Houston's light rail system now runs down the center of that road, making it difficult to cross to the other side, which is where I hoped to find the trail extension. So, I turned right, moved to the left lane, did a U-turn at the first intersection, and headed back the way I came, a less than perfect solution. When I got to where I hoped to find a trail, I found it but also found that it was closed, that it was in the process of being rebuilt. The bad news, no trail extension, no more miles. The good news, the new trail will go under Martin Luther King Boulevard, obviating the difficult crossing, and promises to be as nice as the trail through McGregor Park. Also, there are indications from the City of Houston that this new trail may extend further down Braes Bayou, closing some gaps along the way. The dream is to have this trail extended all the way to the Ship Channel, which is the extension of Buffalo Bayou. Although there would be more gaps to fill, ultimately this could connect the Braes Bayou Trail with the Buffalo Bayou Trail and thus to the White Oak Bayou trail, creating over 40 miles of continuous trails along Houston's Bayous.

In the lower left corner can be seen a small bit of the new concrete trail through McGregor Park. Just above and to the right can be seen the start of a new trail that branches off and goes under Martin Luther King Boulevard. On the other side of the Bayou can be seen what looks to be a dirt path but in fact is the beginning of another new paved trail.

All of this new trail construction is exciting and wonderful, with the one reservation that it seems to frequently involve tearing up existing trails, trading current biking opportunities for future ones. Along those lines, the thing I saw on this ride that was most discouraging was a series of "Trail Closed" signs, not on the trail, but next to it, suggesting that closures of this, my trail of last resort, were imminent. In my next post, I will tell you how that played out, but, spoiler alert, my next post is about the west end of the Buffalo Bayou trail. Finally, two posts from now, I will discuss how Bike Houston, our bicycle advocacy group, is working with the City of Houston to better manage this conflict between present and future cycling infrastructure. Stay tuned.

Bike Plan Pep Rally

I miss most of the social rides here in Houston because I am on a reverse schedule. Most rides are before or after work or on the weekend to accommodate working cyclists. As a retired cyclist with a working wife, I am free during the work day but spend other times with my wife and am not available for rides. Thus, I was very excited when the Bike Houston, the main cycling advocacy group here in Houston, was having a bike ride and rally during the working day when I could attend.

Headquarters of Bike Houston, start of the ride

Granted, this was not really a social ride. Rather, it was a political rally to encourage the Houston City Council to adopt the Houston Bike Plan, a "guide for the City of Houston to achieve the vision of making Houston a safer, more accessible gold-level bike-friendly city within 10 years." The City of Houston Planning & Development Department in coordination and cooperation with a number of other city departments, funding agencies, and cycling advocacy groups developed the plan, which now needs to be passed by the Houston City Council. Its passage is far from a sure thing; some members of the City Council feel that the development described in the plan is a waste of money and oppose it, thus this ride and rally.

Start of the ride. Note the dress and demographics. Tattoos are visible upon close examination. Photo taken by the Houston Press.

This event consisted of three parts. The first part was a symbolic ride beginning at the Bike Houston headquarters, picking up riders along the way representing different constituencies, and meeting up with additional advocates outside Houston City Hall. The second part then began, a rally on the plaza in front of Houston City Hall. Finally, some members of the group then went inside to participate in a public meeting of the Houston City Council to speak on behalf of and otherwise show support for the Bike Plan. I participated in the first two parts.

On the road. The woman on the right in the turquoise shirt is Mary Blitzer of Bike Houston who lead the ride. Photo taken by the Houston Press

The symbolic ride was just over 2 miles long, was ridden very slowly, and featured multiple stops in service to its symbolic mission, and barely qualified as a ride. However, I chose to ride from home to Bike Houston, and then from City Hall back home, giving me a 15 mile ride, nothing special but not a complete loss from a riding perspective. That said, I could have easily had a much better ride had I not chosen to participate, so why did I? Partly to support the Houston Bike Plan; the more people who were on the ride, the more people at the rally, the clearer a signal that is sent to City Hall. But the bigger motivating factor was curiosity; despite having been a Bike Houston member for two years, I had no idea who these folks were. I wanted to meet them and see what one of their rides looked like, even if it was an atypical ride.

To help show the range of riders who benefit from the plan, these riders are on B-Cycle bikes, the bike share program in the city of Houston. Photo taken by the Houston Press.

I was quite nervous leading up to the ride. In the first place, Bike Houston headquarters is located in a neighborhood named "Midtown" located just southwest of downtown Houston, a neighborhood which is a bit difficult to reach by bicycle because getting there requires riding on some busy streets. Even after extensive route planning, I remained nervous. In the second place, and I know how silly this sounds, I worried as to the proper attire for the event. Riding with the Houston Randonneurs or the Houston Bike Club, the traditional brightly colored lycra road cycling gear is in order, but for this political demonstration, would street clothes be expected? I ended up wearing cycling clothes, selecting a jersey from a charity ride and baggy shorts as something of a compromise. When I got to Bike Houston, I found that I was well outside both the dress code and demographics; the very young crowd favored baggy urban wear and visible tattoos. There were one or two other riders dressed more like I was, but we were the distinct minority. As best I could tell, though, nobody cared. About 30 of us left Bike Houston Central and headed off to City Hall. In the lead was an electric-assisted cargo bike ridden by Mary Blitzer, Manager of Community and Government Relations for Bike Houston, pulling a trailer-mounted "white" memorial bike to remind the City Council of the life and death stakes of the Bike Plan.

Proof I was actually there. On the left is John Long, Executive Director for BikeHouston and on the right is The Zombie himself. Two of the activities featured at the rally were to have riders fill out cards expressing their support for the plan, which I am holding, and to have their picture taken inside this frame. This picture was provided by Bike Houston. I can no longer find the site on which it was shared.

So how was it? What did I accomplish? It is too early to know, if we ever will, what was accomplished. As of this writing, almost a month after the ride and rally, the Houston City Council has still not adopted the bike plan, but who knows what that means? Do events like this have any impact? Honestly, I have no idea. As to how it was, I am very glad I participated. Firstly, had I not confronted my trepidation and just done it, I would have been disappointed with myself. Secondly, whether it ended up mattering or not, at least I did something to support cycling in Houston. Thirdly, I got to know the Bike Houston demographic; despite talking to virtually nobody, I feel like I made some friends, in a creepy stalker kind of way. If I ever encounter another opportunity to ride with this crew again, I'd jump at it. All in all, quite the success from my point of view.

Quantitating Intensity

My experience riding at different intensities. HR Zone (Heart rate zone) was related to BPM (Heart Rate in Beats Per Minute) as described in Joe Friel's "Cycling Training Bible." BPM and MPH (Speed in miles per hour) were measured using a Garmin Edge cycle computer and heart rate monitor. Power (in Watts) was estimated from speed using the website at http://bikecalculator.com/. Four intensity models were compared: RPE (Relative Perceived Exertion) was based on my subjective RPE estimated as described in Thomas Chapple's "Base Building for Cyclists". RNP (Relative Normalized Power) was calculated from my Power estimate as described in the text below. Similarly, calculation of HR (heart rate) is described in the text as well. The final column, labelled Gillen et al., used the heart rates for Moderate and Vigorous exercise as well as their relative intensities from the Mayo Clinic website and the relative intensities of Moderate vs. Intense exercise from the Gillen et al. paper. Based on the description of Intense exercise in that paper, I determined that it corresponds to HR Zone 5c. All intensity estimates in the final four columns were normalized to the intensity of a ride in HR Zone 2.

Introduction

I have spent more time on this blog post than any other I have written, and thus it is discouraging that this is also the post about which I am most uncertain. Preparing this post took so much time because of the amount of reading and thinking it required. My uncertainty comes from the fact that I argue that the entire exercise community is wrong about how to measure intensity, and I have very little standing from which to make such an extravagant claim. So, after all that apologizing, what is intensity?

Bicycle rides can be characterized by volume (e.g. how many hours a ride lasts) and intensity (e.g. how fast the ride was, all things considered.) Together, these factors determine load¹, how much the ride improves fitness and causes fatigue. These two things are not necessarily the same, so for the purposes of this post, I am going to consider only how intensity affects fitness.

Volume seems like it should be relatively simple to measure and understand, even quantitatively; it would seem logical that a two hour ride would have twice the volume of a one hour ride. However, it is not certain that the second hour of a ride provides the same fitness benefit as the first did², perhaps it provides more benefit, perhaps less. However, most coaches assume that, for the purposes of measuring volume, the first and second hours are equivalent, and for the purposes of this post, so will I. If quantifying load is problematic, quantifying intensity is much more so. In the first place, there are many different things people measure to get at intensity; speed, power, and heart rate for example. In the second place, there are many different ways people calculate intensity from such measurements. It seems obvious that a 20 MPH bike ride is more than twice as hard as a 10 MPH bike ride, but how much harder?

Measuring Intensity

In addition to speed, power, and heart rate listed above, the volume of oxygen that is used per minute (VO2), the level of lactate in the blood, and relative perceived exertion have also been used as measures of intensity. Relative perceived exertion is the subjective measure of how tiring a ride feels and turns out to be a very useful measure despite its subjectivity. Speed is relatively easy to measure but is affected by hills, wind, type of bicycle, etc. Power is conceptually similar to speed except that it requires an expensive ($500 to $1,000) power meter to measure and is not affected by hills, wind, type of bicycle, etc., so is easier to interpret. In addition, it takes more than twice the power to go 20 mph than it does to go 10 mph, so power may come closer to reflecting intensity than does speed.

In contrast to speed and power which measure what is happening externally (to the bicycle) some of the other measures determine what it happening internally (to the cyclist). Heart rate is one such measure. Compared to power, heart rate can be measured inexpensively, $50 will purchase a perfectly adequate heart rate monitor. It is my impression that heart rate (beats per minute or bpm) is the most common way endurance athletes measure effort (with the possible exception of relative perceived exertion.) It is important to note that different measurements are, in fact, measuring different things. Heart rate, besides estimating load on the heart itself, seems to integrate a wide variety of bodily stressors, things such as heat, cold, fear, fatigue, etc. Blood lactate may be the best measure of fatigue of the leg muscles themselves, especially as they go anaerobic. VO2 measures the extent to which leg muscles are using their aerobic energy system.

How do the experts quantitate ride intensity? In "The Cyclist's Training Bible", Joe Friel suggests assigning a subjective "hardness" to each training ride, a number between 1 and 10, and to use that as a measure of intensity, a measure similar to Relative Perceived Exertion. As a (preferred) alternative, Friel recommends a software package, TrainingPeaks, which (among other things) estimates intensity. Based on what I read on the TrainingPeaks website, I believe the measure of intensity they use is Relative Normalized Power (RNP). The Power part of that is straightforward; it is what is measured by a power meter. The Relative is necessary because generation of 200 watts of power might represent much more intensity for me than it does for you. To make power relative, the power of a ride is expressed as the ratio of that power to Functional Threshold Power, the power used in a 30 minute time trial. Normalized means that the power is averaged over a training session. In "Base Building for Cyclists", Thomas Chapple recommends using Heart Rate Zone as a measure of intensity; a bike ride ridden in Heart Rate Zone 5 would have five times the intensity as one ridden in Heart Rate Zone 1.

To me, all of the measures of intensity discussed above seem arbitrary; there is no rationale given for why intensity should be proportional to subjective feel, heart rate, or power. When I researched the issue, I was unable to find any evidence in support of any of these. The only experimental data I have found that speaks to intensity measurement is Gillen et al. (which I have previously blogged about not once but twice) and Gillen et al. gives a very different estimate of intensity than do any of the expert-recommended measures. According to this paper, 1 minute of high intensity exercise (HR Zone 5c) provides the same benefit as 45 minutes of moderate intensity exercise (HR Zone 2.) As an intermediate point, the consensus of the medical community is that 1 minute of vigorous exercise - HR Zone 4 - is equivalent to 2 minutes of moderate exercise - HR Zone 2. All of this is summarized in the table at the top of this post. In contrast, the metrics suggested by Friel and Chapple suggest that high intensity intervals (HR Zone 5c) has 3 to 4 times the intensity as moderate exercise. Thus, Gillen et al. disagrees significantly from the consensus of the exercise community.

Is it reasonable to override the opinions of highly experienced and successful coaches like Friel and Chapple based on a single scientific publication? Normally, I would be reluctant to do so, but in this case I suspect that, if pressed, Friel and Chapple would not cling to their estimates, and thus I am inclined to go with Gillen et al. There are two reasons I think Friel and Chapple may not be wedded to their metrics. The first is that, in the context of their books, these metrics are mentioned only once and in a rather off-hand manner; they do not constitute a significant part of any training plans. The second is that if you look at the high intensity interval plans that Friel suggests (Chapple's book only covers base training and thus contains no high intensity intervals), the length and number of repeats of these intervals is more consistent with the higher estimate of their intensity provided by Gillen et al. than it is with Friel's own metric. I suspect that neither Friel nor Chapple use the intensity calculations from their books to design training schedules for their clients. Rather, I would suggest they draw upon their experience and introduce rides of different intensity when their experience tells them their clients are ready for them.

The Value of Intensity Quantitation

If experienced coaches like Friel and Chapple don't feel a need for an accurate measure of intensity, why should we? For the purposes of training (which is what Friel and Chapple care about) I suspect we don't. There are so many factors affecting training (e.g. illness, stress at work, person to person variation) that it would still be necessary to constantly adjust training plans even if there were an accurate measure of intensity. Is it possible that at the highest levels of the sport, the Tour de France or the olympics for example, an accurate metric for intensity would allow coaches to bring elite athletes to a slightly higher peak of performance? Perhaps, but I am not even certain of that. My interest is more in the science, the understanding of how exercise affects our bodies. In fact, the impetus for this post was a paper by Stöggl and Sperlich.

The Stöggl and Sperlich publication argues in favor of polarized training, a training plan that emphasizes training at either very high intensity or very low intensity and minimizes training at moderate intensity. To provide evidence for that generalization, they compared four training plans that varied in the percentage of time spent at different intensities, and found that the plan that was the most "polarized" was the best. I wondered if there could be explanations other than polarization as to why the "polarized" plan did the best. For example, it is broadly accepted that training plans can be too easy, too hard, or just right. Without knowing a great deal more than I do about the athletes participating in the study, it is impossible to know where in that spectrum any specific plan falls, but conceptually, it should be possible to see if the four plans are equally hard, or if some are harder than others. However, when I attempted to determine this back then, I found that I could not because I did not know how to compare intensities. Have I now gotten past that barrier? As noted at the top of this post, I am very uncertain of the metric for intensity I am proposing here, but that said, I will answer with a hearty "maybe." To answer this question, I first converted their LOW, LT and HIGH levels of exercise to HR zones³, translated the description of the different protocols in Stöggle and Sperlich into a list of how many minutes of exercise at each HR zone each protocol contained. Using intensities of 1 for Zone 2, 2 for Zone 4, and 45 for Zone 5c, I converted this to a total load for each protocol. These were then normalized such that the lowest intensity protocol had a score of 1. The result was that THR (lactate THReshold, exercise at time trial pace) had a relative load of 1, HVT (High Volume Training, long slow miles) had a relative load of 2, HIIT (High Intensity Interval Training, all out sprinting) had a relative load of 3, and POL (POLarized training, a mix of all out sprinting and long slow miles) had a relative load of 5. Thus, the benefit of the different protocols was related to their load, the greater the load, the greater the benefit. Perhaps it is this higher load rather than polarization that made the POL plan the most beneficial.

Conclusions

I opened this post by apologizing for having the presumption to question the accumulated wisdom of the exercise community, given that I have very little standing from whence to do so. That said, I stand by my conclusions, at least in general. The reason I think the exercise community has gotten this wrong is that quantitative intensity is rarely used, and thus coaches and athletes don't notice how wrong current estimates are. Rather, workouts are designed based on experience and adjusted based on the subjective feelings of the athlete, both approaches which I agree are highly successful. The only time quantitative intensity matters is in a research study, where these two pillars of success are, by necessity, ignored. So, although an accurate estimate of intensity may not be necessary for day to day training, it may be necessary for research on training, and that research has a lot to offer the exercise community in the long run. Thus, I believe an effort to better quantitate intensity is warranted and that Gillen et al. is a good start towards that goal.

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1) Actually, this is external load. Total load included both this external load as well as internal load that comes from non-training factors such as illness, stress, and lack of sleep as well as the leftover fatigue of training done during the prior days and weeks. In this post, I will only consider external load, and use the word load to refer to that.

2) Qualitatively, most training books will tell you that one-two hour ride provides different benefits than two-one hour rides, but beyond that qualitative assertion, I have yet to encounter a quantification of such a difference.

3) The levels of intensity in Stöggl and Sperlich were expressed as levels of lactate in the blood. I used the data contained in Belcher and Pemberton, International Journal of Exercise 5: 148-159, 2012, to convert lactate levels to heart rate zones.