Fast Twitch, Slow Twitch, and Training Regimens

I continue to struggle to come up with a satisfactory training regimen.  I am constantly looking for new sources of information, and a couple of months ago started thinking and reading about the difference between fast twitch and slow twitch muscle fibers.  Fast twitch muscle fibers are used for high intensity, low duration activities like weight lifting and sprinting, and slow twitch muscle fibers are used for endurance activities like most cycling and long distance running. Despite having a Ph.D. in biochemistry and a lifelong career in biomedical research, I was stunned to learn that the preferred fuel for slow twitch muscle fibers is fat!  In all of my research into distance cycling, I kept reading about the importance of eating regularly during a ride to avoid "bonking" due to a lack of carbohydrate (stored in the body as glycogen) when I have enough fat around my waist to ride from Houston to New York City with plenty to spare.  (This is literally true, not an exaggeration.)  Actually, as I continued to read, I learned that muscle cannot use lipid for more than 50% to 70% of its fuel, that the rest needs to be carbohydrate (though I have no idea why this is true), so the need to eat is real, but I only need to eat 30% to 50% of the calories I am burning.  With luck, the rest will come off my waist.  As I researched how I might derive as much of my fuel as possible from fat, I came across a highly recommended book, "The Big Book of Endurance Training and Racing" by Dr. Philip Maffetone and Mark Allen (ISBN 1616080655).

As a card carrying member of the conventional medical establishment, there was a lot that made me uncomfortable about this book.  Its primary author, Dr. Philip Maffetone, is very much a member of the alternative medicine community, but despite that, the book is so focused on the issues about which I am thinking, about how to train your body to favor slow twitch/fat burning muscles rather than fast twitch/carbohydrate burning muscles, I felt like I needed to read it. Although this book considers nutrition, various kinds of muscle manipulation, and even the choice of music best suited for training, I am going to ignore all of that in this post.  Rather, I am going to focus on a novel training regimen recommended in this book which promises to develop your muscles and metabolism to favor fat burning and endurance while minimizing over training and injury.  Better yet, it provides clear predictions as to what to expect so that I can experimentally determine if this approach works for me, something that, as a lifelong scientist, I appreciate very much.

If you are interested in applying the recommendations made in this book to your training, do not try to use the information in this post.  What I have written here is a drastic selection and summarization of just a few points made in the book mixed in with a lot of other things I have been reading and significantly modified by me to come up with a potential training plan targeted to me, my particular interests, and my particular needs.  Rather, if you are interested in this book, buy it and read it.  That said, the rest of this post is the training plan I came up with after reading this book.

If you have been reading very much about training, you probably have come across  formula for calculating your maximum heart rate, most commonly 220 beats per minute minus your age.  I am 63, so this formula would give me a maximum heart rate of 157 beats per minute.  Various kinds of training are to be done at various percentages of this maximum heart rate, typically 50% to 97%.  Dr. Maffetone, on the other hand, is more interested in something he calls the maximum aerobic heart rate which he calculates as 180 beats per minute minus your age plus or minus a correction factor based on your overall health and fitness.  The correction factors are as follows:
  1) If you have recently have been ill or are currently on medication, subtract 10 beats per minute.
  2) If you recently have:
      a. Suffered an exercise injury OR
      b. Have observed "regression" in your "MAF test" (see below) OR
      c. Have been training for less than 2 years:
      Subtract 5 beats per minute.
  3) If you have been training for about two years, don't add or subtract anything.
  4) If you have been training for longer than two years, add 5 beats per minute.
Although I have been riding since 2008, I have been actively training for less than two years, so for me, the calculation is 180 - 63 - 5 = 112 beats per minute.

At the center of  Dr. Maffone's recommendations is what he describes as an apparently easy training session.  What this session consists of for me, which I refer to as an aerobic training ride, is as follows:

1. Warm up for 12 to 15 minutes.  My heart rate should gradually go from my resting heart rate to my maximum aerobic heart rate over that time.
2. Ride for 30 to 45 minutes so as to maintain my heart rate within 10 beat per minute of my maximum aerobic heart rate without going over (102 to 112 beats per minute.)
3. Cool-down for 12 to 15 minutes at the end of the ride.  During the cool down, my heart rate should decline to within 10 to 20 beats per minute over my resting heart rate.

The prediction is that if I do aerobic training rides regularly, my speed should improve without any increase in heart rate, beginning no later than 1 to 2 months after the beginning of training, and should continue to improve every month throughout the season.  To determine if this is true, one is to perform a "MAF Test".  A MAF test is nothing more than the above training ride in which you record your speed during the training part of the ride.

In my blog post, "Another Brevet?", I described the four phases included in most training plans:

• TRANSITION: The rest between seasons.
• FOUNDATION: A base training regimen to provide a foundation for the rest of your season.
• PREPARATION: Training targeted to the events you wish to complete.  
• TAPER: A relaxation in training just before an event to build energy for the event.

Most of the reading I had been doing up until now focused on Preparation and Taper.  In contrast, "The Big Book of Endurance Training and Racing" is at its most specific when describing Foundation.


So what are the events I am targeting?  My goal is to be a randonneur and thus the events are brevet rides as described on the RUSA website.  To this end, I am a member of the Houston Randonneurs who sponsor brevet rides once a month.


Putting it all together, I have developed the following schedule for a one year brevet season:

• TRANSITION: I plan one month of no training between one season and the next.  Given the schedule of the Houston Randonneurs (and Houston weather) this month would be June.
• FOUNDATION: I plan three months of almost daily aerobic training rides with no long distance rides; July, August, and September.  Although these months are very hot in Houston, the aerobic training rides are quite short and can be done in the early morning.
• PREPARATION 1: In preparation for my first brevet of the season, a 200 km brevet, I will replace one of the aerobic training rides each week with a long distance ride.  This ride will start at 40 miles and will increase by 10% each week until the ride reaches 90 miles.  This will take three months; October, November, and December.
• TAPER 1: I will allow at least a week and a half between the last 90 mile training ride and the first brevet.  I will schedule no training rides for the two days before the first brevet.
• PREPARATION 2: During the brevet season, I will eliminate the long training ride each week.  Aerobic training rides will continue and distance training will be provided by the monthly brevet rides, which can vary between 200 and 1200 km.  These will be ridden in January, February, March, April, and May.
• TAPER 2: Because all of my training will come from the brevets themselves, and because these are a month apart, a good part of a Taper will come naturally from that.  In addition, I will schedule no training rides for the two days before each brevet.

The above schedule has a number of problems:

1. It is very rigid.  It has no room for family events, illness, or setbacks.
2. The three months of Foundation training I propose, featuring only aerobic training, are at the low end of what Dr. Maffetone recommends.  Four months of Foundation training might be preferable.
3. It is far from clear that I am capable of completing some of the longer brevet rides.
4. Riding with my wife on weekends is an essential part of my life and a major reason I find cycling fun. Although she is a strong rider and I get a good workout on these rides, her goals are different than mine. She is not interested in training, she just wants to ride.
5. Interesting brevets often occur after May.  For example, Paris-Brest-Paris, which will be next held in 2015, is in August.  (I have posted previously about the difficulty of having to complete the qualifying 200, 300, 400, and 600 km brevets by June and then waiting to ride Paris-Brest-Paris until August.)

I would like to address the first three problems together as they are closely related.  The key to all three is flexibility.  I accept that I don't know what length brevets I am capable of completing.  Testing of this new training regimen includes a test of my ability, at my age, to be a randonneur.  Facilitating this, the Houston Randonneurs often have a 200K option at the same time as whatever brevet they are running that month.  Thus, if I find at the end of three months I need more Foundation training, I will extend Foundation training by a month and do my first 200 km brevet in February instead of January.  Similarly, should life intervene, I will simply revise the schedule as necessary so as to not reduce the Foundation training, but to delay the start of my brevet training as necessary.  If I find that 200 km or 300 km or some other length brevet is as long as I can tolerate, I will simply choose brevets that length or shorter.

The third problem is how I integrate this new training schedule with recreational rides with my wife. Although it might be ideal to do aerobic training rides six days a week, riding with my wife is more important to me than advancing my career as a randonneur.  Thus, during Foundation for example, I plan to do aerobic training rides four days a week, to rest one day a week, and to spend Saturday and Sunday riding with my wife with neither plan nor heart rate monitor.  Honestly, I doubt this will negatively impact my training at all, but even if it does, that is my plan and I am sticking to it.

Finally, the answer to the fourth problem, how should I alter my training schedule if I want to ride brevets after May, is anticipated by Dr. Maffetone.  He suggests splitting a long season into two parts, with a month and a half of base training (short aerobic rides) inserted between.  For example, should I be fit enough to attempt Paris-Brest-Paris in 2015, I might complete the brevet series needed to qualify by the beginning of April, repeat base training for the remainder of April and much of May, and then spend the rest of May, June, and July training for Paris-Brest-Paris.  This, of course, would require adjustments to the schedule the following year, but this is a bridge I will happily cross should I be so fortunate to come to it.

Three final points:

1. Obviously, it is too late to execute this plan for the 2013.  What have I been doing so far to prepare for 2013, and in light of my new training plan, what should I do for the remainder of 2012?  Answering these questions will be the topic of a future blog post.
2. At the beginning of this post, I expressed some reservations about the "alternative" aspects of Dr. Maffetone's ideas.  Given those reservations, why should I invest so heavily in testing Dr. Maffetone's training schedule, and conversely, why am I not looking to the conventional medical establishment for training ideas?  These are questions I have asked myself and in response, my wife helped me by finding the following chapter in a Medical School textbook: "Exercise Physiology and Sports Science" by Steven S. Segal in "Medical Physiology: A Cellular and Molecular Approach, 2nd Edition" edited by Walter F. Bron and Emile L. Boulpaep (ISBN 978-1-4377-1753-2).  In addition, I have read the publicly available lecture notes from Dr. David Q. Thomas' courses in exercise physiology from Illinois State University.  I find these all very interesting, but nothing I have read therein would discourage me from trying Dr. Maffetone's training regimen.  On the other hand, neither the textbook nor the lectures offer much in the way of practical training advice of their own.  Nonetheless, as a card carrying member of the medical establishment, I intend to continue reading this literature so I will know the parameters within which training strategies should lie.
3. Dr. Maffetone's book is intended for young racers.  I am not a young racer, I am an old man whose goal is to finish brevets within their time limits.  Dr. Maffetone's book is not unique in this regard, very little of the training literature is written for me.  That said, the fact that Dr. Maffetone's recommended training regime is so gentle even though targeted at a much more aggressive demographic makes it all the more attractive.

In the end, I have purchased a heart rate monitor and will be trying Dr. Maffetone's training ideas.  In future posts, I will report how they worked for me.  Finally, I still have many other questions about training and will research and discuss these in future posts as well.