Friday, August 19, 2016

Working on muscle fatigue

The Tinman Triathlon closed out the serious part of my race season for this year, leaving the Honolulu Century Ride and the Honolulu Marathon to close out the year. Prior to Honu I was undecided about doing the marathon. The thought of another long training sequence was not very appealing. I guess I got bored during the long taper to Tinman, made a week longer by tropical storm Darby, as that is when I decided to get serious about the marathon, joined Jason Fitzgerald's Strength Running group and began planing my fall workout schedule.

After Tinman I thought about what my challenges had been. What happened that failed to meet my expectations? What seemed to be keeping me from going faster? This is not a question without merit, in that I routinely finish near last place. If those other athletes are going so much faster, what do I need to do to be more like them?

For any athlete who asks that question -- are there any who don't? -- the first thing they will probably turn to is physique. The assumption that those other guys are faster because they are gifted. They have bigger lungs. Longer legs. Longer arms. Shorter legs. Smaller bodies. They are taller. Shorter. Thinner. Ripped.

It seems to me that there are certain physical features that contribute to success in certain events, but this only applies to a handful of people. Besides, there isn't much I can do about the length of my legs. What I can do, and work hard at, is to develop my form to the best of my ability, to learn how to arrange my body parts to make the most of what I have.

After we accept out body as perfectly suited to the task at hand we come to skill. Technique. I can't do anything about the length of my legs, but I can learn to move them in ways that allow me to perform better. Skill comes in two parts, knowledge and practice. I happen to love the knowledge part. I really enjoy studying technique, be it from books, videos, or conversations with experts. The practice part is not as much fun, but I am as consistent and conscientious as anyone. One thing is always true about technique: you can never stop working to improve. Especially swimming. The difference between a slow swimmer and a fast swimmer is for the most part a bunch of very small deviations from ideal form.

For endurance athletes -- for me at least -- the thing that comes right after skill is muscular endurance. However good our skill is, we need to repeat the muscle contractions that create that movement over and over again. What I notice is that towards the end of a long event my muscles start to complain a lot. I try to take inspiration from cyclist Jens Voigt's famous line, "Shut up, legs!" but that is never enough to keep me going. I first learned that "muscular endurance" was a thing because it is listed as a limiter on Training Peaks. Joe Friel goes into more detail in his books, such as "The Triathlete's Training Bible,"Chapter 6, "Training Advanced Abilities."

At last year's marathon I slowed considerably, walking a lot after mile 18. I was at my target pace until then, but missed my plan by a wide margin. At Honu I was exhausted after the swim and genuinely surprised how little power I could produce on the bike. At Tinman I had planned to run the entire 10K, in spite of the hills, but even before I got to Monsarrat I had to walk just to keep moving -- my legs felt like lead. I decided that I needed to focus on muscular endurance.

After deciding to look deeper into the subject of muscular endurance I found that, as so often is the case, there are multiple and sometimes conflicting views of what it is and how to improve. The "what it is" part can be divided into two camps. One, the older group, say it is physiological. Here is an example of one such description. I do enjoy the details.

How to Offset Muscle Fatigue.  Runner's World, October 8, 2009.

Joe Friel's discussion is similar, though less detailed. "A high level of muscular endurance results from adaptation of the mechanical properties of the muscles to resist fatigue, an elevated LT (lactate threshold -- gd) and tolerance of lactate that slowly accumulates at such intensities."

The other camp, of more recent vintage, claim that the physiological explanation is wrong, that the real limiter is the mind. Here are two articles that take this position:

Perception of effort, not muscle fatigue, limits endurance performance., March 19,2010.

Why Endurance Athletes Should Re-Think Fatigue. Bicycle Lab.

 I have decided to blend these two points of view together. I think it is obvious that an increase in muscular endurance cannot be achieved without physical training, and even if the mind-over-matter theory sounds a bit far out, it cannot hurt to include it in one's mental fitness training.

This does not mean the matter is resolved. Not at all. The next question is, what to do during workouts to increase muscular endurance. And, once again, I find differing opinions from people I have the utmost respect for.

There is one thing everyone agrees on. A good way to improve muscular endurance is do long intervals at or just below LTHR, either running or on the bike. Runners are likely to call this a tempo run. There appears to be a lot of flexibility in how long to make the work interval, but one thing they all have in common is a relatively long work interval and a short recovery. Apparently doing this very much above your LTHR does not produce the desired response, as you are actually stressing your anaerobic system, with the likely outcome of an extended recovery period -- several days before another quality workout can be attempted.

I decided to get started with something simple, done on the bike until the century ride at the end of September, then switching over to the run until the marathon in December

Bike: 3 x 12 min at 90% FTP, 2:30 recovery

Run: 3 x 12 min at 95% LTHR, 2:30 recovery

I figured that if I made significant improvement I could increase the working duration, something like this:

2 x 20 min at 95% LTHR, 2:30 recovery

LTHR is right at the start of zone 5. A lot of sources describe doing tempo runs at HR zone 3. For me, 90% LTHR comes in at low zone 3, 95% at very top of zone 3. The bike version is based on using a power meter, just figure that heart rate at FTP is LTHR. Same physiologic condition expressed a different way.

Now that I know what to do, the next step is, when and how often. To answer the second question first, at my age I only have room for one long run per week and one quality run per week. All the more so because I am still training as a triathlete even though my next goal race is a marathon. I had considered adding these to my calendar, making for two quality runs per week. The only available slot was Friday morning, the day before my long run. Jason Fitzgerald recommended against this plan, and I agree. So my weekly run schedule goes something like this:

Mon. Base run, 3 mi.
Wed. Quality run
Sat. Long run, 12-18 miles

I think hill repeats are another excellent workout, too good to ignore, and I am fortunate to live near a perfect hill for run and bike intervals. I plan to alternate hill work with track work, hills more for power and the track more for muscular endurance.

One more thing. As marathon training proceeds, the long run should finish at race pace. In Build 1 the long run should be done entirely at no higher than mid zone 2, with considerable time at the start in zone 1. It is during Build 2, the last three to four weeks before peak that the long run pace should be pushed for the last couple miles, to get the body and mind conditioned to running at that pace even while fatigued. Based on the articles mentioned above, this is as much about the mind as it is the muscles.

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