Stamina

In the previous installment, we began our exploration of training mind, body, and craft for endurance events by laying the foundation for Why you run and What you expect to get out of it. Those are critical questions to answer before a complementary training program can be developed because many of the decisions within the program will be directed by those answers, and the answers are unique to you. The answers may also change over time; so they should be revisited from time-to-time. Remember that we’re creating your personalized training philosophy in these early stages of plan development, and our working definition of philosophy is ‘a frame-work for making decisions’.

Once you know Why you’re running and What you expect to get out of your running, you can progress to How you’ll train and, possibly, race. You don’t have to race; you may want to take on personal adventures or simply train to improve.

And so let us begin to develop How you’ll train. Today, we’re drafting the architecture of training the body.

If you don’t have a background in the physiology of exercise, but you’re curious enough to read some books, I have a brief list of books that I recommend on the resources page of scienceofultra.com. There you’ll find that a couple of the books are focused on exercise science. There are many basic textbooks on exercise physiology meant for college classes and any of those would be suitable for a solid background. But, that background is not necessary to grasp what’s to come from this series of Science Of Ultra podcast episodes.

I know many of my listeners are into pursuits other than ultra-marathons, such as triathlon, swim-run, and even ultra-distance biking, among others. What's the purpose of training in the context of improving for these endeavors? Ultimately, you want to be able to complete the distance (or time) either a) at a given pace while making it feel easier or b) to complete the distance faster (or cover more distance in the same time).

What we’re talking about is stamina. Stamina is your ability to maintain a pace for a long time. Stamina comprises endurance and economy. Endurance is your ability to cover a distance or to persist for a time. Endurance has nothing to do with effort level in my framework. Instead, endurance is purely your ability to endure - to continue without resting - for a given distance or a given time. Can you move your body 50 miles without taking a significant rest? If yes, then you have the endurance for 50 miles. Economy is a traditionally quantified as the steady state oxygen consumption at a given running velocity. There are important discussions around whether this is the right measurement, but those nuances won’t impact how you construct your training with regard to improving economy. For our purposes, economy of running is the energy required to run at a given pace. Generally, the goal is not to reduce your energy requirements for a given pace but rather to go faster for the effort though those tend to go together. For example, you may want to be able to run faster while at 70% maximum effort. Improving economy gives you the ability to do that. As Greg Lemond said, “it doesn’t get any easier, you just get faster”.

Let’s put it all back together. Stamina is your ability to maintain a pace for a long time, such as the distance of a race. Stamina is the outcome of endurance (your ability to move a distance without significant rest) and economy (your ability to make the same effort feel easier and to go faster for the same effort).

So, what are the most fundamental abilities you want to develop when training your body? Endurance and economy. Then you want to put them together for stamina.

You develop endurance by running as much as you can while staying injury-free. This requires running at very easy effort. It surprises me how often I get asked ‘what heart rate equates to an easy effort?’. There is no heart rate for easy - easy is an effort. Easy is easy. If you wonder whether you’re at an easy pace, then it’s probably too fast. You know when it’s easy. If we have to put a number on it, then know that the upper limit of the bioenergetic domain we’re talking about is very commonly 70% of HRmax, maybe 75% for better trained athletes. However, there’s appreciable variance and you shouldn't get locked into numbers. About 85% of your total running time each week should be easy (below 70% of HRmax if your justing getting a sense for how things should feel). I emphasize that this is not an average but an upper limit; if you use the heart rate estimate, then 70% of max is your upper limit, not the average to aim for.

Now we have to remind ourselves of the most important training parameter, the law of consistency. There's nothing more important in your development than consistency. It's better to run 30 minutes on 6 days per week than to run 1 hour three days per week. The first goal is to increase the number of days per week that you run until you’ve reached 5 or 6 days per week, leaving one or two days for rest or easy cross-training. Then, start increasing the duration of your easy runs. Introduce some variability in the durations of your easy runs among the days in a week as you get past 30 minutes per day; for example, working up to 6 days of running where durations are 2 days of 2 hrs, 3 days of 1 hr, and 1 day of 0.5 hours for a total of 7.5 hours of running per week or, on a 10 hr per schedule, something like 1 day of 3 hrs, 2 days of 2 hrs, and 3 days of 1 hr (that’s 1, 2, and 3 days of 3, 2, and 1 hr, respectively). The point is to not run exactly the same time every day of the week once you have some baseline fitness and are building your volume. Generally, I prefer to not have the two longest runs back-to-back but to have a shorter run between them, except in the 6-8 weeks prior to a goal event. 

This overall plan structure applies to people first starting to run and also to top runners on the podium, with the specific numbers scaling to the athlete's capacity. At the elite and professional levels, we’ll include two workouts per day on some or even most days but that’s outside the scope of this episode. 

Endurance development occurs through steady and incremental increases in duration (or distance). Steadily nudging each run up for an increase of about 10% total duration or distance per week is a reasonable rate though the number can be 15% when the total is low and closer to 5% if the total is very high. If you start to get injured or don’t feel recovered after your rest day, it’s time to back off a bit. Don’t rely on any devices or external numbers to tell you when to take extra rest. Learn how to listen to your body and mind - there is no better set of tool than your internal sensors for tracking and monitoring your levels of fatigue. If you feel drained, don’t look for a number on a watch to confirm, refute, or otherwise modify that sense - trust yourself.

There’s no need to increase running duration or distance indefinitely. You won't be running 50 hrs a week some time in the future. Eventually, you’ll find your upper limits. Ultra-marathon pros have been successful on 50 miles a week, with a few on even less at times. But, elite marathon runners (and some ultra-marathon runners) are often doing well more than 100 miles per week. It seems that 50-70 miles per week is a good range that most people can eventually sustain without injury. Again, back off if you feel niggles or other symptoms of wear and tear. If you continue to have those issues whenever you get up to a certain weekly time or mileage, then stay below that value for six or more months before pushing it again. But know that you may have found your own sweet spot. 

The bioenergetics and physiological responses to continued running in this easy domain of intensity will differ among people depending on their relative capacity for that intensity. One way to quantify this is observing cardiac drift, which is the increase in heart rate while maintaining a steady pace. In the easy domain, when we’ve reached the sort of capacity we’re aiming for, there should be little or no cardiac drift over at least one hour. So, test this on yourself by starting an easy run that brings heart rate to somewhere between 60% and 65% of HRmax by 10-15 minutes into the run. Maintain that pace for one hour. At the end of the hour, your heart rate should not have risen more than 5 beats. This test is trickier to do if you run over varied terrain, like trails. But, you can repeat a short loop or find a route with consistent ups and downs throughout the hour, set a screen on your watch to show average lap pace then press lap every 10-15 minutes. Maintain the average pace throughout the run and look a heart rate afterwards - there should be no more than a 5 beat per minute rise from the first lap or segment to the last. You don’t need heart rate to do this if you can really tap into your perception of effort, which is actually a better test - the pace should feel just as easy at the end of the hour as it did 15 minutes into it. I recommend doing this test on at least two days just to be sure that results are not skewed by anything strange on a single day.

If your heart rate or effort are drifting up higher while maintaining a truly easy pace for an hour, then you will benefit from increasing the volume of easy running that you’re doing. You should focus changes in your training program on increasing the volume of easy running before adding any significant workouts of higher intensity.

Once you’re running at least 5 days per week and are able to complete an easy run for at least an hour without an increase in heart rate of more than 5 beats per minute or without a noticeable increase in your effort to maintain the pace, I like to begin introducing features during workouts that develop economy. The first feature to introduce are strides. Strides are near-sprints that last for 20 seconds; that’s 3-5 seconds for gentle acceleration then for 15 seconds or so you’re going as fast as you can over level or nearly level ground while keeping your upper body loose. There should be absolutely no tension or straining in the upper body; only your legs are working. My athletes will generally do 4-6 strides with about 1-2 minutes of easy running for full recovery on 2-3 days each week. The purpose of these is to develop economy. They should never cause fatigue; you should always finish the set of strides feeling springy and energized, not tired at all. Often, the first one may feel a little sluggish. But, by the last, you should feel revitalized.

Now we’re getting onto the next topic. So this is the right place to stop for today. Today’s episode is meant to introduce the key concepts and functional goals of improving endurance and economy so that you can improve stamina, which is the capacity to run faster for longer. Today, we also explained endurance as a capacity and how to increase endurance within the context of consistency for sufficient and relative weekly volumes. We also outlined how to progress training volume of easy running and how to test your bioenergetic and physiological capacity profile with an easy run test. Then we added strides as a salvo into developing economy.

The next feature to add into the program for improving running economy is short intervals. And that’s a topic for its own post. Developing economy, will be the topic of the next post on training your body. Then, within our ‘training the body’ sub-series, we’ll explore my favorite topic, bioenergetics, to unpack and demystify training intensity domains - sometimes called zones.